Systems and methods for processing ammonia

Abstract

The present disclosure provides a method of making a catalyst for ammonia decomposition, the method including: (a) subjecting a catalyst support to one or more physical or chemical processes to optimize one or more pores, morphology, and / or surface chemistry or properties of the catalyst support, (b) depositing a composite support material onto the catalyst support, the composite support material including a morphology or surface chemistry or properties, and (c) depositing one or more active metals onto at least one of the composite support material and the catalyst support, the one or more active metals including one or more nanoparticles configured to conform to the morphology of the composite support material and / or the catalyst support material, thereby optimizing one or more active sites on the nanoparticles for ammonia processing.

Description

[Technical field]

[0001] cross reference This application claims priority to U.S. Provisional Patent Application No. 63 / 257,904, filed October 20, 2021, and U.S. Provisional Patent Application No. 63 / 209,530, filed June 11, 2021, each of which is incorporated by reference in its entirety for all purposes. [Background technology]

[0002] A fuel source can be used to operate a variety of systems. A fuel source can have a specific energy that corresponds to the amount of energy that can be stored or extracted per unit mass of fuel. A fuel source can be provided to a variety of systems to enable such systems to generate energy and / or provide power (e.g., for travel or transportation). Summary of the Invention

[0003] Hydrogen can be utilized as a clean energy source to power a variety of systems. Hydrogen can provide distinct advantages over other types of fuels, such as diesel, gasoline, or jet fuel, which have a specific energy of about 45 megajoules per kilogram (MJ / kg) (heat), or lithium-ion batteries, which have a specific energy of about 0.95 MJ / kg (electricity). In contrast, hydrogen has a specific energy (heat) of over 140 MJ / kg. Thus, 1 kg of hydrogen can produce the same amount of energy as about 3 kg of gasoline or kerosene. Thus, hydrogen as a fuel source can help reduce the amount of fuel (by mass) required to produce an equivalent amount of energy as other conventional fuel sources. Additionally, systems that use hydrogen as a fuel source (e.g., as a combustion reactant) generally produce harmless or non-toxic by-products, such as water, while minimizing or nearly eliminating harmful emissions, such as carbon dioxide and nitrous oxide emissions, thereby reducing the environmental impact of various systems (e.g., vehicles) that use hydrogen as a fuel source.

[0004] Various limitations of conventional catalysts used to extract hydrogen from ammonia (e.g., by ammonia decomposition processes or reactions) are recognized herein. Ammonia decomposition may also be referred to as ammonia cracking, ammonia reforming, or ammonia dissociation. Ammonia decomposition may be a highly structure-dependent reaction, and the ability to control the morphology and / or physical or chemical properties of the active metal nanoparticles used to decompose the ammonia molecule may be limited when using conventional catalyst manufacturing methods. Therefore, optimal use of active metal nanoparticles is difficult, and in many cases conventional catalysts contain higher than optimal active metal nanoparticle content. Furthermore, the nanoparticles may not be highly dispersed, which may reduce the efficiency of the catalyst. Conventional catalysts may also exhibit low heat transfer rates, which are undesirable for endothermic ammonia decomposition reactions. Conventional catalysts may also lack stability at high temperatures, in the presence of impurities in industrial grade ammonia, or under mechanical perturbation, as well as being unable to withstand harsh reaction conditions or maintain the physical and chemical properties required to optimally crack ammonia. Some conventional catalysts may include bead, extrudate, or pellet type catalyst supports, but when the catalyst material is compressed into these shapes, the inner material of the pellets may not be fully utilized, which may be wasteful and inefficient. As used herein, the morphology of the active metal nanoparticle support may correspond to the size, shape, aspect ratio, pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure of one or more active metal nanoparticles. As used herein, the physical or chemical properties of the active metal nanoparticles may include the size, size distribution, aspect ratio, facet distribution, Arrhenius acidity or basicity, Lewis acidity or basicity, or hydrophilicity or hydrophobicity of one or more active metal nanoparticles.

[0005] The present disclosure provides systems and methods to address at least the above-mentioned shortcomings described for conventional catalysts. Some embodiments of the present disclosure are directed to optimized catalyst materials, related systems and methods for producing such optimized catalyst materials, and methods of using such optimized catalyst materials. The optimized catalyst materials can exhibit optimal morphology and / or physical or chemical properties for the active metal nanoparticles used to promote the decomposition of ammonia. The physical or chemical properties can include the surface chemistry or properties of one or more active metal nanoparticles. The optimized catalyst materials can also exhibit optimal levels of dispersion of the active metal nanoparticles. The optimized catalyst materials can further maintain favorable physical and chemical properties under harsh reaction conditions and can exhibit high thermal stability and optimal heat transfer rates to enable efficient endothermic ammonia decomposition reactions.

[0006] The present disclosure further provides methods for producing catalysts with optimized material composition, active metal nanoparticle morphology, surface chemistry or properties, and / or interactions with supported metals. The manufacturing methods disclosed herein can be implemented to create catalytic materials with high thermal stability and optimized heat transfer properties. The catalytic materials produced using the methods disclosed herein can be used to efficiently decompose ammonia at lower reaction temperatures for longer periods of time compared to conventional catalysts, and can extract greater amounts of hydrogen per unit weight or volume of ammonia while using lower concentrations of active metals (e.g., lower ruthenium content).

[0007] The present disclosure further provides one or more catalysts for treating ammonia. The one or more catalysts can have, for example, an optimized pore structure and morphology and / or surface chemistry or properties of active metal nanoparticles. The catalytic material of the present disclosure can have high thermal stability and optimized heat transfer properties. The catalytic material may be used to efficiently decompose ammonia at lower reaction temperatures, and can extract a greater amount of hydrogen per unit weight or volume of ammonia while using a lower concentration of active metal. In some cases, more hydrogen can be produced using the same amount of catalytic material. In some cases, hydrogen can be made at a lower reaction temperature.

[0008] In one aspect, the present disclosure provides a method of making a catalyst for ammonia processing or decomposition, the method including: (a) providing a catalyst support; (b) thermally, chemically, physically, or electrochemically treating the catalyst support to change pore characteristics of the catalyst support; (c) depositing a composite support material on the catalyst support, where the composite support material has a morphology or surface chemistry or characteristics; and (d) depositing one or more active metals on at least one of the composite support material and the catalyst support, where the one or more active metals include one or more nanoparticles configured to conform to the morphology or surface chemistry or characteristics of the composite support material when subjected to thermal or chemical treatment, thereby optimizing one or more active sites on the nanoparticles for ammonia processing or decomposition.

[0009] In some embodiments, the morphology includes pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure. In some embodiments, the surface chemistry or property includes elemental composition, Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, or hydrophilicity or hydrophobicity. In some embodiments, thermally, chemically, physically, or electrochemically treating the catalyst support includes subjecting the catalyst support to one or more thermal, chemical, physical, or electrochemical processes or treatments to optimize one or more pores or surface chemistry or properties of the catalyst support. In some embodiments, optimizing one or more pores includes (i) modifying one or more pore sizes, (ii) modifying the pore volume of the catalyst support, (iii) modifying the pore size distribution, or (iv) modifying the pore density of the catalyst support. In some embodiments, optimizing the surface chemistry or properties includes altering (i) the Arrhenius acidity or basicity, (ii) the Lewis acidity or basicity, (iii) the surface hydroxyl group density, or (iv) the hydrophilicity or hydrophobicity of the surface.

[0010] In some embodiments, the composite support material is deposited using physical vapor deposition or chemical vapor deposition. In some embodiments, the morphology or surface chemistry or properties of the composite support material follow the morphology or surface chemistry or properties of the catalyst support. In some embodiments, the one or more active metals are deposited using physical vapor deposition or chemical vapor deposition. In some embodiments, the method can further include thermally or chemically activating the one or more active metals. In some embodiments, thermally, physically, chemically, or electrochemically activating the one or more active metals induces the growth of one or more nanoparticles of the active metal. In some embodiments, the one or more nanoparticles are configured to grow while following the morphology or surface chemistry or properties of the composite support material when thermally, physically, electrochemically, or chemically activated. In some embodiments, the method can further include combining the catalyst with one or more promoters to modify or optimize the morphology, active sites, electron density, Arrhenius acidity or basicity, Lewis acidity or basicity, or electronic state of the catalyst.

[0011] In some embodiments, the one or more promoters comprise sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba). In some embodiments, the one or more active metals comprise ruthenium (Ru), nickel (Ni), rhodium (Rh), iridium (Ir), cobalt (Co), molybdenum (Mo), iron (Fe), platinum (Pt), chromium (Cr), palladium (Pd), or copper (Cu). In some embodiments, the catalyst support comprises aluminum oxide (Al2O3), magnesium oxide (MgO), cerium dioxide (CeO2), silicon dioxide (SiO2), yttrium oxide (Y2O3), zirconium oxide (ZrO2), one or more zeolites, titanium dioxide (TiO2), lanthanum oxide (La2O3), chromium oxide (Cr2O3), or calcium oxide (CaO). In some embodiments, the composite support material comprises a carbon-based material, a boron-based material, or a metal oxide. In some embodiments, the carbon-based material comprises graphite, activated carbon (AC), one or more carbon nanotubes (CNTs), one or more carbon nanofibers (CNFs), graphene oxide (GO), one or more carbon nanoribbons, or reduced graphene oxide (rGO). In some embodiments, the boron-based material comprises hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs). In some embodiments, the metal oxide comprises aluminum oxide (Al2O3), titanium dioxide (TiO2), magnesium oxide (MgO), lanthanum oxide (La2O3), cerium dioxide (CeO2), yttrium oxide (Y2O3), one or more CeO2 nanotubes, nanorods or nanocubes, mesoporous silica, zirconium dioxide (ZrO2), chromium oxide (Cr2O3), or calcium oxide (CaO).In some embodiments, the composite support material can include yttria stabilized zirconia (YSZ), hydrotalcite (MgAl-LDO), metal organic frameworks (MOFs) (e.g., MIL-101), zeolitic imidazolate frameworks (ZIFs), alkali amides (NaNH, Ca(NH), Mg(NH), inorganic electrides (e.g., C12A7:e-), halloysite nanotubes (HNTs), ABO3 perovskite, AB2O4 spinel, mesoporous silicates (e.g., MCM-41), or any combination thereof.

[0012] In some embodiments, the method may further include thermally, physically, chemically, or electrochemically treating the surface of the catalyst support material to optimize the pore structure or surface chemistry or properties of the catalyst support material. In some embodiments, the one or more ammonia molecules are configured to bind or attach to one or more active sites on the active metal to decompose the one or more ammonia molecules. In some embodiments, the location, orientation, and / or density of the one or more active sites are determined based at least in part on the morphology and / or surface chemistry or properties. In some embodiments, the catalyst support comprises a bead, pellet, powder, thin film, monolith, foam, reactor wall, heating element, one or more wires, mesh, or porous solid material shape. In some embodiments, the pore properties include pore structure, pore size, pore size distribution, pore shape, pore volume, or pore density. In some embodiments, the method may include modifying the pore density of the catalyst support. In some embodiments, the method may include increasing the pore density of the catalyst support.

[0013] In another aspect, the present disclosure provides a catalyst for ammonia processing, the catalyst comprising: a catalyst support comprising one or more modified pore characteristics produced by thermal, physical, chemical, or electrochemical treatment of the catalyst support; a composite support material disposed on the catalyst support, the composite support material comprising a morphology or surface chemistry or property; and one or more active metals disposed on or incorporated into at least one of the composite support material and the catalyst support, the one or more active metals including one or more nanoparticles configured to conform to the morphology or surface chemistry or property of the composite support material when thermally, physically, chemically, or electrochemically activated, thereby optimizing one or more active sites on the nanoparticles for the processing or decomposition of ammonia.

[0014] In some embodiments, the morphology includes pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, particle size, grain shape, crystal structure, flake size, or layered structure. In some embodiments, the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, hydrophilicity or hydrophobicity. In some embodiments, the catalyst support comprises one or more properties or characteristics that can be optimized using one or more physical or chemical processes. In some embodiments, the one or more properties or characteristics include the morphology or surface chemistry or properties of the catalyst support. In some embodiments, the morphology includes pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, particle size, grain shape, crystal structure, flake size, or layered structure. In some embodiments, the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, or hydrophilicity or hydrophobicity. In some embodiments, the composite support material is deposited using physical vapor deposition or chemical vapor deposition. In some embodiments, the morphology or surface chemistry or properties of the composite support material follow the morphology or surface chemistry or properties of the catalyst support. In some embodiments, the one or more active metals are deposited using physical vapor deposition or chemical vapor deposition. In some embodiments, the one or more active metals are configured to follow the morphology or surface chemistry or properties of the composite support material when thermally or chemically activated. In some embodiments, the one or more active metals are configured to grow when thermally, physically, chemically or electrochemically activated. In some embodiments, the one or more nanoparticles are configured to grow while following the morphology or surface chemistry or properties of the composite support material.

[0015] In some embodiments, the catalyst is combined with one or more promoters. In some embodiments, the one or more promoters include Na, K, Rb, Cs, Mg, Ca, Sr, or Ba. In some embodiments, the one or more active metals include Ru, Ni, Rh, Ir, Co, Mo, Fe, Pt, Cr, Pd, or Cu. In some embodiments, the catalyst support includes Al2O3, MgO, CeO2, SiO2, Y2O3, one or more zeolites, TiO2, or ZrO2. In some embodiments, the composite support includes a carbon-based material, a boron-based material, or a silicon-based material, or a metal oxide. In some embodiments, the carbon-based material includes graphite, activated carbon (AC), one or more carbon nanotubes (CNTs), one or more carbon nanofibers (CNFs), graphene oxide (GO), one or more carbon nanoribbons, or reduced graphene oxide (rGO). In some embodiments, the boron-based material comprises hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs). In some embodiments, the silicon-based material comprises silicon carbide (SiC), silicon nitride (SiN), or silicon dioxide (SiO2). In some embodiments, the metal oxide comprises TiO2, MgO, La2O3, CeO2, Y2O3, one or more CeO2 nanotubes, nanorods, or nanocubes, mesoporous silica, ZrO2, chromium oxide (Cr2O3), or calcium oxide (CaO). In some embodiments, the support comprises YSZ, hydrotalcite (Mg2Al-LDO), MOF (MIL-101, ZIF), alkali amide (NaNH2, Ca(NH2), Mg(NH2), MgAl2O4, CaAl2O4, CoAl2O4, inorganic electride (C12A7:e-), halloysite nanotubes (HNT), ABO3 perovskite, AB2O4 spinel, MCM-41, or any combination thereof. In some embodiments, the morphology or surface chemistry or properties are generated or optimized by thermally, physically, chemically, or electrochemically treating the surface of the catalyst support material.In some embodiments, the one or more active metal nanoparticles comprise one or more active sites to which one or more ammonia molecules are configured to attach or bind for decomposition of the one or more ammonia molecules. In some embodiments, the location, orientation, or density of the one or more active sites is determined at least in part based on morphology or surface chemistry or properties. In some embodiments, the catalyst support comprises the shape of a bead, pellet, powder, thin film, monolith, foam, reactor wall, heating element, wire, mesh, or porous solid material.

[0016] In another aspect, the present disclosure provides a system for manufacturing a catalyst for ammonia processing, the system comprising: a rotatable reaction chamber comprising one or more heating units, the reaction chamber configured to process one or more catalyst supports to produce one or more catalysts optimized for ammonia processing; and one or more precursor storage chambers in fluid communication with the rotatable reaction chamber, the one or more precursor storage chambers configured to supply a plurality of precursor materials comprising: (i) a first precursor material comprising one or more functional materials providing a base for nanoparticle growth, (ii) a second precursor material comprising one or more active metal nanoparticles, and (iii) a third precursor material for promoting the one or more active metal nanoparticles.

[0017] In some embodiments, the one or more heating units are configured to heat the one or more catalyst supports to optimize one or more features or properties of the one or more catalyst supports. In some embodiments, the one or more features or properties include morphology or surface chemistry or properties. In some embodiments, the one or more features or properties include pore size, pore density, or pore volume. In some embodiments, the morphology includes pore structure, pore size, pore shape, pore volume, pore density, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure. In some embodiments, the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, or hydrophilicity or hydrophobicity.

[0018] In some embodiments, the rotatable reaction chamber comprises one or more inlets for receiving the first precursor material to deposit a layer of the first precursor material on the surface of the one or more catalyst supports. In some embodiments, the layer of the first precursor material is deposited using physical vapor deposition or chemical vapor deposition. In some embodiments, the morphology or surface chemistry or properties of the first precursor material follow the morphology or surface chemistry or properties of the one or more catalyst supports. In some embodiments, the morphology includes pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure. In some embodiments, the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, or hydrophilicity or hydrophobicity.

[0019] In some embodiments, the layer of the first precursor material provides a base for the growth of one or more active metal nanoparticles. In some embodiments, the rotatable reaction chamber is configured to receive the second precursor material to deposit a layer of the second precursor material on at least one of (i) the surface of the one or more catalyst supports and (ii) the layer of the first precursor material. In some embodiments, the one or more active metal nanoparticles of the second precursor material are configured to grow on the layer of the first precursor material. In some embodiments, the one or more active metal nanoparticles are configured to grow according to the morphology or surface chemistry or properties of the first precursor material when thermally or chemically activated. In some embodiments, the layer of the second precursor material is deposited using physical vapor deposition, chemical vapor deposition, vacuum deposition, wet impregnation, or incipient wetness impregnation. In some embodiments, the morphology includes pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure. In some embodiments, the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, or hydrophilicity or hydrophobicity.

[0020] In some embodiments, the rotatable reaction chamber is configured to receive a third precursor material for doping the layer of the first precursor material, the layer of the second precursor material, or for promoting one or more active metal nanoparticles of the second precursor material. In some embodiments, doping includes impregnating the layer of the first precursor material or the layer of the second precursor material with one or more dopants. In some embodiments, promoting includes impregnating the layer including one or more active metal nanoparticles with one or more promoters for modifying morphology, modifying active sites, modifying electron density, modifying Arrhenius acidity or basicity, modifying Lewis acidity or basicity, or modifying electronic state. In some embodiments, the one or more promoters include Na, K, Rb, Cs, Mg, Ca, Sr, or Ba.

[0021] In some embodiments, the one or more heating units are configured to heat the catalyst support comprising (i) a layer of a first precursor material and (ii) a layer of a second precursor material to thermally, physically, chemically, or electrochemically activate the one or more active metal nanoparticles to promote growth and change in one or more properties or characteristics of the nanoparticles. In some embodiments, the rotatable reaction chamber is configured to provide a reducing environment for thermal or chemical activation of the one or more active metal nanoparticles. In some embodiments, the reducing environment comprises hydrogen or ammonia gas, or one or more noble gases. In some embodiments, the one or more active metal nanoparticles comprise Ru, Ni, Rh, Ir, Co, Mo, Fe, Pt, Cr, Pd, or Cu. In some embodiments, the catalyst support comprises Al2O3, MgO, CeO2, SiO2, Y2O3, AC, CNT, CNF, GO, rGO, hBN, BNNT, BNNS, SiC, SiN, MgAl2O4, CaAl2O4, CoAl2O4, one or more zeolites, TiO2, or ZrO2. In some embodiments, the one or more functional materials comprise a carbon-based material, a boron-based material, or a metal oxide. In some embodiments, the carbon-based material comprises graphite, activated carbon (AC), one or more carbon nanotubes (CNTs), one or more carbon nanofibers (CNFs), graphene oxide (GO), one or more carbon nanoribbons, or reduced graphene oxide (rGO). In some embodiments, the silicon-based material comprises silicon carbide (SiC), silicon nitride (SiN), or silicon dioxide (SiO2). In some embodiments, the boron-based material comprises hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs). In some embodiments, the metal oxide comprises TiO2, MgO, La2O3, CeO2, Y2O3, one or more CeO2 nanotubes, nanorods or nanocubes, mesoporous silica, ZrO2, chromium oxide (Cr2O3), or calcium oxide (CaO).In some embodiments, the support comprises YSZ, hydrotalcite (Mg2Al-LDO), MOF (MIL-101, ZIF), alkali amide (e.g., NaNH2, Ca(NH2)2, Mg(NH2)2), MgAl2O4, CaAl2O4, CoAl2O4, inorganic electride (C12A7:e-), halloysite nanotubes (HNT), ABO3 perovskite, AB2O4 spinel, MCM-41, or any combination thereof.

[0022] In some embodiments, the rotatable reaction chamber is in fluid communication with one or more gas sources, including a reactive gas, hydrogen gas, or one or more noble gases. In some embodiments, the reactive gas can be used to chemically modify or optimize one or more pores of the catalyst support. In some embodiments, the hydrogen gas and one or more noble gases can be used to provide a reducing environment during thermal, physical, chemical, or electrochemical activation of one or more active metal nanoparticles.

[0023] In some embodiments, the system may further comprise one or more mass flow controllers for controlling the flow of fluids or materials into and out of the rotatable reaction chamber. In some embodiments, the system may further comprise a vacuum pump in fluid communication with the rotatable reaction chamber for providing a vacuum environment within the rotatable reaction chamber. In some embodiments, the system may further comprise an additional heating unit for heating or pre-heating multiple precursor materials.

[0024] Another aspect of the present disclosure provides a non-transitory computer-readable medium containing machine-executable code that, when executed by one or more computer processors, performs any of the methods described above or elsewhere herein.

[0025] Another aspect of the present disclosure provides a system comprising one or more computer processors and a computer memory coupled thereto, the computer memory including machine executable code that, when executed by the one or more computer processors, performs any of the methods described above or elsewhere herein.

[0026] Another aspect of the present disclosure is a method for producing a ferroelectric material comprising: a O b In some embodiments, the catalyst includes a support including a ZrO 2 doped with cerium (Ce) and oxygen (O), a layer disposed adjacent to the support, and one or more active metal particles disposed adjacent to the layer. In some embodiments, "a" and "b" are numbers greater than zero. In some embodiments, the layer includes a ZrO 2 doped with cerium (Ce) and oxygen (O). c O d where "c" and "d" are numbers greater than zero. In some embodiments, the molar ratio of Ce to Zr in the layer ranges from about 1:5 to about 1:25, and the catalyst is configured to decompose ammonia. In some cases, "a" is 1 and "b" is 2. In some embodiments, the layer comprises CeO2. In some embodiments, "c" is 1 and "d" is 2. In some embodiments, the cerium in the layer is configured to upshift the center of the d-band of one or more active metal particles. In some embodiments, the cerium in the layer is configured to increase the metal-support interaction of one or more active metal particles on the layer. In some embodiments, the cerium in the layer is configured to increase the 3P band of one or more active metal particles on the layer. 3 / 2 In some embodiments, the (Ce x O y) may increase metal-support interactions. In some embodiments, the cerium in the layer is configured to decrease the metal-nitrogen bond energy during the ammonia decomposition reaction. In some embodiments, the cerium in the layer is configured to increase the electron occupancy in the metal-nitrogen antibonding molecular orbital during the ammonia cracking reaction. In some embodiments, the molar ratio of Ce to Zr ranges from about 1:8 to about 1:12.

[0027] In some embodiments, the support further comprises aluminum oxide, silicon oxide, or carbon. In some embodiments, the aluminum oxide comprises Al2O3 or the silicon oxide comprises SiO2. In some embodiments, the layer comprises an amorphous, monoclinic, or tetragonal network structure of (Zr:Ce)O2. In some embodiments, the support comprises ZrO2 having an amorphous, monoclinic, or tetragonal phase. In some embodiments, the layer comprises a plurality of nanoparticles comprising ceria. In some embodiments, the ceria comprises CeO2. In some embodiments, the layer comprises a plurality of nanoparticles comprising CeO2. 3+ ions and Ce 4+ ions, and in some cases Ce 3+ Ion Ce 4+ ions range from about 0.3:1 to about 0.9:1. In some embodiments, the Ce 3+ Ion and Ce 4+ The ratio of ions ranges from about 0.7:1 to about 0.8:1. In some embodiments, the catalyst exhibits an X-ray powder diffraction (XRD) spectrum exhibiting a lower diffraction angle compared to a corresponding XRD spectrum of an undoped catalyst that does not include a layer containing cerium, and optionally the catalyst comprises about 10 mol% to about 15 mol% Ce. In some embodiments, a catalyst comprising at least about 20 mol% Ce exhibits a ceria peak as measured by XRD.

[0028] In some embodiments, the catalyst is configured to induce oxygen vacancies in the range of about 0.1 millimoles (mmol) / gram (g) to about 10 mmol / g. In some embodiments, the oxygen vacancy concentration is about 2 mmol / g to about 6 mmol / g. In some embodiments, the catalyst is configured to obtain a density of acid sites in the range of about 10 micromoles (μmol) / gram (g) to about 1000 μmol / g. In some embodiments, the acid site concentration is about 50 μmol / g to about 300 μmol / g.

[0029] In some embodiments, the support comprises one or more promoters configured to modify the basicity of the support. In some embodiments, the one or more promoters comprise one or more members selected from the group consisting of alkali metals and alkaline rare earth metals. In some embodiments, the one or more active metal particles are 3p 3 / 2 The electrons in the orbital have binding energies of 460 eV to 465 eV for Ru and Ni 2p 1 / 2 The 3d orbital electrons of Ni and Rh have binding energies of 870 eV to 880 eV. 3 / 2 The 4f orbital of Rh and Ir has a binding energy of 305 eV to 315 eV. 7 / 2 Ir and Co have binding energies of 55 eV to 65 eV for the electrons in the orbital 2p 1 / 2 Co, Fe 2p orbital electrons have binding energies of 790 eV to 805 eV 1 / 2 The binding energy of the electrons in the orbital of Fe and Pt is 720 eV to 735 eV. 7 / 2 Pt, Cr 2p orbital electrons with binding energies of 67 eV to 75 eV 1 / 2 3d orbital electrons of Cr and Mo have binding energies of 585 eV to 595 eV 3 / 2 Mo and Pd have a binding energy of 230 eV to 240 eV for the electrons in the 3d orbital. 3 / 2 Orbital electrons have binding energies of 335 eV to 345 eV for Pd and Cu 2p 1 / 2and Cu, which has a binding energy of 950 eV to 965 eV for the electrons in the orbital. In some embodiments, the one or more active metal particles comprise one or more metals selected from the group consisting of Ru, Ni, Rh, Ir, Co, Fe, Pt, Cr, Mo, Pd, and Cu.

[0030] In some embodiments, the layer comprises one or more nanoparticles or nanorods comprising ceria. In some embodiments, the one or more nanoparticles or nanorods are adjacent to and attached to the support. In some embodiments, the one or more nanoparticles or nanorods are formed by co-impregnation of KOH and Ce(NO3)3. In some embodiments, at least 90% by weight of the catalyst is larger than 1 millimeter (mm) along at least one dimension.

[0031] The present disclosure also provides a method for producing a catalyst, the method comprising: (a) (i) adding Ce x O y or a precursor thereof, and (ii) Zr s O t or precursors thereof, where "x", "y", "s", and "t" are numbers greater than zero, to produce a support comprising cerium (Ce), zirconium (Zr), and oxygen (O); and (b) depositing precursors of one or more active metals adjacent to the support to produce a catalyst, the catalyst configured to decompose ammonia. In some embodiments, the method further includes (b) heating the support to a target temperature, where (b) is performed at the target temperature. In some embodiments, "x" is 1 and "y" is 2. In some embodiments, Ce is a fluorine-containing compound. x O y In some embodiments, "s" is 1 and "t" is 2. In some embodiments, Zr s O tIn some embodiments, (a) is carried out with an oxide comprising cerium (Ce), zirconium (Zr), and oxygen (O). In some embodiments, (a) is carried out with an oxide comprising CeO2 and ZrO2. In some embodiments, the heating is carried out in the presence of an inert gas. In some embodiments, the method includes the step of: s O t Ce x O y In some embodiments, the method includes doping a support comprising cerium (Ce), zirconium (Zr), and oxygen (O) with a precursor of Ce. x O y Precursor of Zr s O t with a precursor of to produce a support comprising cerium (Ce), zirconium (Zr), and oxygen (O).

[0032] In some embodiments, Ce x O y Precursors of include Ce(NO3)3, cerium nitrate hexahydrate, cerium nitrate xhydrate, cerium chloride, cerium oxide, cerium oxide nanofibers, cerium fluoride, cerium chloride, cerium chloride heptahydrate, cerium chloride hydrate, cerium acetate hydrate, cerium sulfate, cerium nitrate hydrate, cerium nitrate hexahydrate, cerium bromide, cerium ammonium nitrate, cerium acetylacetonate hydrate, cerium iodide, cerium hydroxide, cerium ammonium sulfate dihydrate, cerium sulfate tetrahydrate, cerium carbonate hydrate, or cerium sulfate hydrate. In some embodiments, Zr s O tThe precursors include zirconium n-butoxide, zirconium acetylacetonate, zirconium propoxide, zirconium oxychloride, zirconium hydroxide, zirconium oxide, zirconium oxide nanofibers, zirconium ethoxide, zirconium acetate, zirconium hydroxide, zirconium trifluoroacetylacetonate, zirconium hydride, zirconium acetylacetonate, zirconium chloride, zirconium sulfate hydrate, zirconium butoxide, zirconium carboxyethyl acrylate, zirconium oxynitrate hydrate, zirconium propoxide, or zirconium fluoride.

[0033] In some embodiments, the target temperature ranges from about 600° C. to about 1200° C. In some embodiments, the target temperature ranges from about 700° C. to about 1000° C. In some embodiments, the target temperature is at least about 700° C., at least about 800° C., or at least about 900° C. In some embodiments, the precursor of the one or more active metals comprises a Ru precursor, a Ni precursor, a Rh precursor, an Ir precursor, a Co precursor, a Fe precursor, a Pt precursor, a Cr precursor, a Mo precursor, a Pd precursor, or a Cu precursor. In some embodiments, the support comprises one or more promoters configured to modify the basicity of the support. In some embodiments, the one or more promoters comprise one or more elements selected from the group consisting of an alkali metal and an alkaline rare earth metal. In some embodiments, (a) further comprises drying the support in a vacuum prior to depositing the one or more promoter or dopant precursors. In some embodiments, drying the support comprises using a vacuum oven. In some embodiments, the Ru precursor comprises ruthenium iodide, ruthenium acetylacetonate, ruthenium chloride hydrate, ruthenium oxide hydrate, ruthenium chloride, bis(cyclopentadienyl)ruthenium, ruthenium nitrosylnitrate, ruthenium iodide hydrate, triruthenium dodecacarbonyl, or any combination thereof. In some embodiments, the catalyst comprises about 0.2% to about 20% by weight of ruthenium. In some embodiments, the catalyst comprises about 0.5% to about 5% by weight of ruthenium.

[0034] In some embodiments, (a) further comprises (iii) using a promoter or a promoter precursor to obtain a target molar ratio of promoter to Ce in the support. In some embodiments, the promoter precursor comprises a K precursor, an alkali metal precursor, or an alkali rare earth metal precursor. In some embodiments, the alkali metal of the alkali metal precursor comprises Li, Na, K, Rb, Cs, or Fr. In some embodiments, the alkali rare earth metal of the alkali rare earth metal comprises Mg, Ca, Sr, Ba, or Ra. In some embodiments, the promoter precursor comprises potassium methylate, potassium tetrafluoroborate, potassium hydrogen fluoride, potassium thiocyanate, potassium disulfite, potassium bisulfate, potassium sulfide, potassium methoxide, potassium trifluoroacetate, potassium dioxide, potassium persulfate, potassium formate, potassium bicarbonate, potassium sorbate, potassium hydroxide, potassium borohydride, potassium dichloroacetate, potassium iodide, potassium chlorate, potassium fluoride, potassium chloride, potassium nitrate, potassium perchlorate, potassium cyanate, or potassium hexachloroiridate. In some embodiments, the promoter precursor is processed in an aqueous solution. In some embodiments, the promoter precursor is processed in an organic solution. In some embodiments, the target molar ratio of promoter to Ce ranges from about 0.1:1 to about 3:1. In some embodiments, the target molar ratio of promoter to Ce is about 1:1.

[0035] In some embodiments, the method includes drying the support under vacuum or in an inert environment, heating the support to a first target temperature, and dissolving a promoter precursor, Ce, on the support under hydrogen at a second target temperature. x O y , Zr s O t, and reducing the mixed oxides thereof. In some embodiments, the second target temperature is different from the first target temperature. In some embodiments, drying the support includes using a vacuum oven. In some embodiments, heating includes heat treatment under an inert gas. In some embodiments, heating includes heat treatment under air. In some embodiments, the first target temperature is in the range of about 600°C to about 1200°C. In some embodiments, the first target temperature is in the range of about 700°C to about 1000°C. In some embodiments, the first target temperature is at least about 700°C, at least about 800°C, or at least about 900°C. In some embodiments, the second target temperature is in the range of about 250°C to about 600°C. In some embodiments, the second target temperature is in the range of about 250°C to about 450°C. In some embodiments, the second target temperature is at least about 200°C, at least about 300°C, or at least about 400°C. In some embodiments, one or more XRD peaks of the catalyst include a lower diffraction angle when the catalyst includes a K promoter and is treated by heating under an inert gas compared to one or more corresponding XRD peaks of a catalyst that does not include a promoter. In some embodiments, one or more XRD peaks of the catalyst include a higher diffraction angle when the catalyst includes a K promoter and is treated by heating under air compared to the corresponding XRD peaks of a catalyst that does not include a promoter and a lower diffraction angle compared to the corresponding XRD peaks of zirconia that is not doped with ceria. In some embodiments, the catalyst is configured to obtain an XRD peak of CeO2 and the promoter is K.

[0036] In some embodiments, the method further comprises using one or more promoter precursors after (b) to obtain a target molar ratio of promoter to Ce in the support, where the promoter is reduced under hydrogen at the target temperature. In some embodiments, the one or more promoter precursors comprise a K precursor, an alkali metal precursor, and / or an alkali rare earth metal precursor. In some embodiments, the alkali metal of the alkali metal precursor comprises Li, Na, K, Rb, Cs, or Fr. In some embodiments, the alkali rare earth metal of the alkali rare earth metal comprises Mg, Ca, Sr, Ba, or Ra. In some embodiments, the one or more promoter precursors include potassium methylate, potassium tetrafluoroborate, potassium bifluoride, potassium thiocyanate, potassium disulfite, potassium bisulfate, potassium sulfide, potassium methoxide, potassium trifluoroacetate, potassium dioxide, potassium persulfate, potassium formate, potassium bicarbonate, potassium sorbate, potassium hydroxide, potassium borohydride, potassium dichloroacetate, potassium iodide, potassium chlorate, potassium fluoride, potassium chloride, potassium nitrate, potassium perchlorate, potassium cyanate, or potassium hexachloroiridate. In some embodiments, the one or more promoter precursors are processed in an aqueous solution. In some embodiments, the one or more promoter precursors are processed in an organic solution. In some embodiments, the target molar ratio of promoter to Ce ranges from about 0.1:1 to about 3:1. In some embodiments, the target molar ratio of promoter to Ce is about 1:1. In some embodiments, the target temperature ranges from about 250°C to about 600°C. In some embodiments, the target temperature ranges from about 250°C to about 450°C. In some embodiments, the target temperature is at least about 200° C., at least about 300° C., or at least about 400° C. In some embodiments, the promoter is configured to modify the basicity of the complex oxide support. In some embodiments, the promoter is configured to increase the electron density of the active metal to promote the detachment of recombined nitrogen and / or the cleavage of N-H bonds.In some embodiments, the support comprises one or more nanorods comprising ceria. In some embodiments, the ceria is CeO2. In some embodiments, the catalyst is powderless.

[0037] In another aspect, the present disclosure provides a method for decomposing ammonia, comprising decomposing ammonia using a catalyst disclosed herein to produce at least hydrogen. In some aspects, the present disclosure provides a method for decomposing ammonia, comprising decomposing ammonia using a catalyst made by a method disclosed herein to produce at least hydrogen. In some embodiments, the active metal is Ru, the promoter is K, and the molar ratio of Ru to K is 1:1, and decomposing ammonia converts about 98% of the ammonia at a temperature of about 500° C.

[0038] Other aspects and advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, in which only exemplary embodiments of the present disclosure have been shown and described. As will be understood, the present disclosure is capable of other and different embodiments, and its several details are capable of modification in various obvious respects, all without departing from the present disclosure. Accordingly, the drawings and description should be regarded as illustrative in nature, and not as restrictive.

[0039] Incorporation by Reference All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. To the extent that the publications and patents or patent applications incorporated by reference conflict with the disclosure contained in the specification, the specification supersedes and / or takes precedence over any such conflicting content.

[0040] The novel features of the invention are set forth with particularity in the appended claims. The features and advantages of the present invention will be better understood by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also referred to herein as "figures"), of which: [Brief description of the drawings]

[0041] [Figure 1] FIG. 1 illustrates generally an exemplary system for processing ammonia to produce hydrogen fuel, according to some embodiments.

[0042] [Diagram 2] FIG. 2 illustrates a schematic of an exemplary method of hydrogen storage using liquid chemicals, according to some embodiments.

[0043] [Diagram 3] FIG. 3 illustrates a schematic of an exemplary hydrogen extraction reactor including a heterogeneous catalyst, according to some embodiments.

[0044] [Figure 4] FIG. 4 illustrates generally various types of modifications and processes for optimizing catalytic materials, according to some embodiments.

[0045] [Diagram 5] 5 and 6 generally illustrate an exemplary process for modifying and upgrading a catalyst support, according to some embodiments. [Figure 6] Same as above.

[0046] [Figure 7] FIG. 7 illustrates generally an exemplary process for processing precursor materials, according to some embodiments.

[0047] [Figure 8A] FIG. 8A illustrates a schematic illustrating the effect of catalyst reduction on ammonia conversion efficiency, according to some embodiments.

[0048] [Figure 8B] FIG. 8B illustrates a schematic illustrating the effect of heat treating a catalyst on hydrogen production or generation rate, according to some embodiments.

[0049] [Figure 8C] FIG. 8C illustrates a schematic illustrating the effect of active metal promotion of a catalyst on ammonia conversion efficiency, according to some embodiments.

[0050] [Figure 8D] FIG. 8D illustrates a schematic illustrating the effect of doping the catalyst on ammonia conversion efficiency, according to some embodiments.

[0051] [Figure 8E] FIG. 8E illustrates a schematic illustrating the effect of doping the catalyst on ammonia conversion efficiency, according to some embodiments.

[0052] [Figure 9] FIG. 9 illustrates generally an exemplary system for producing various catalytic materials, according to some embodiments.

[0053] [Figure 10] FIG. 10 illustrates generally a computer system that may be programmed or configured to carry out the methods provided herein.

[0054] [Figure 11] FIG. 11 illustrates a comparison of ammonia conversion efficiencies of various catalysts synthesized using different ruthenium precursors, according to some embodiments.

[0055] [Figure 12] FIG. 12 illustrates a comparison of ammonia conversion efficiencies using various catalysts synthesized using alumina supports of various sizes, according to some embodiments.

[0056] [Figure 13] FIG. 13 illustrates a comparison of ammonia conversion efficiencies of various catalysts synthesized by reduction at various temperatures, according to some embodiments.

[0057] [Figure 14] FIG. 14 illustrates a comparison of ammonia conversion efficiencies of various catalysts synthesized using various gamma- and theta-alumina supports, according to some embodiments.

[0058] [Figure 15] FIG. 15 illustrates a comparison of ammonia conversion efficiencies of various catalysts synthesized with different La to Ce ratios, according to some embodiments.

[0059] [Figure 16] FIG. 16 illustrates a comparison of ammonia conversion efficiencies of various exemplary catalysts manufactured using different combinations of materials and manufacturing methods, according to some embodiments.

[0060] [Figure 17A] FIG. 17A illustrates a comparison of ammonia conversion efficiency of various catalysts having different La:Ce molar ratios, and the variation in ammonia conversion efficiency based on changing Ce content, according to some embodiments.

[0061] [Figure 17B] FIG. 17B illustrates a comparison of ammonia conversion efficiency of various catalysts having different La:Ce molar ratios, and the variation of ammonia conversion efficiency based on different operating temperatures, according to some embodiments.

[0062] [Figure 18] FIG. 18 illustrates a comparison of ammonia conversion efficiencies of various catalysts doped with rare earth metals, according to some embodiments.

[0063] [Figure 19]FIG. 19 shows a table of elemental compositions of various catalysts doped with rare earth metals, according to some embodiments.

[0064] [Figure 20] FIG. 20 provides examples of some methods contemplated herein for improving the efficiency of Ru to ammonia conversion, according to some embodiments.

[0065] [Figure 21A] FIG. 21A shows a comparison of hydrogen production rates of catalysts of the present disclosure, according to some embodiments, with conventional catalysts.

[0066] [Figure 21B] FIG. 21B shows a table describing the conditions under which the catalyst shown in FIG. 21A was tested, according to some embodiments.

[0067] [Figure 22] FIG. 22 shows the ammonia conversion efficiency of various catalysts as a function of temperature, according to some embodiments.

[0068] [Figure 23A] FIG. 23A shows powder X-ray diffraction (pXRD) spectra of supports containing various amounts of ceria and zirconia, according to some embodiments.

[0069] [Figure 23B] FIG. 23B shows the ammonia conversion efficiency of various catalysts as a function of temperature, according to some embodiments.

[0070] [Figure 24A] 24A-24B show pXRD spectra of different catalysts according to some embodiments. [Figure 24B] Same as above.

[0071] [Figure 24C] FIG. 24C shows the ammonia conversion efficiency of catalysts according to some embodiments.

[0072] [Figure 25A] FIG. 25A shows pXRD spectra of supports containing various amounts of ceria and zirconia, according to some embodiments.

[0073] [Figure 25B] FIG. 25B shows the electron binding energy of electrons in the 3P3 / 2 orbital of ruthenium provided on a support, measured using X-ray photoelectron spectroscopy (XPS), according to some embodiments.

[0074] [Figure 25C] FIG. 25C shows the Ce3+ / Ce4+ ratio measured using XPS according to some embodiments.

[0075] [Figure 26A] 26A-26B show pXRD spectra of supports and catalysts, respectively, annealed at various temperatures, according to some embodiments. [Figure 26B] Same as above.

[0076] [Figure 26C] FIG. 26C shows the ammonia conversion efficiency of catalysts according to some embodiments.

[0077] [Figure 27A] FIG. 27A shows the ammonia conversion efficiency of various catalysts, with the potassium impregnation step being sequentially varied between each catalyst, according to some embodiments.

[0078] [Figure 27B] FIG. 27B shows the electron binding energy of electrons in the 3P3 / 2 orbital of ruthenium provided on a support, measured using X-ray photoelectron spectroscopy (XPS), according to some embodiments.

[0079] [Figure 28A]28A-28B show XPS spectra of ruthenium and cerium, respectively, according to some embodiments. [Figure 28B] Same as above.

[0080] [Figure 29A] 29A-29B show the ammonia conversion efficiencies of various annealed or reduced RuP catalysts, respectively, according to some embodiments. [Figure 29B] Same as above.

[0081] [Diagram 30] FIG. 30 shows a comparison of untreated mesoporous silica pellets (left), mesoporous silica pellets oxidized at 1050° C. (center), and mesoporous silica pellets oxidized at 1200° C. (right), according to some embodiments.

[0082] [Diagram 31] FIG. 31 shows the ammonia conversion efficiency of Ru supported on oxidized mesoporous silica doped with cerium, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0083] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the invention. It will be appreciated that various alternatives to the embodiments of the invention described herein may be employed.

[0084] Whenever the terms "at least," "greater than," or "greater than or equal to" appear after the last number in a series of two or more numbers, the terms "at least," "greater than," or "greater than or equal to" always apply to every number in the series. For example, 1, 2, or 3 or more is equivalent to 1 or more, 2 or more, or 3 or more.

[0085] When the term "less than", "less than" or "less than" appears after the last number in a series of two or more numbers, the term "less than", "less than" or "less than" applies to each number in the series. For example, 3, 2, or 1 or less is equivalent to 3 or less, 2 or less, or 1 or less.

[0086] The terms "real-time" or "real-time," as used interchangeably herein, generally refer to an event (e.g., an operation, process, method, technique, calculation, computation, analysis, visualization, optimization, etc.) that is performed using recently obtained (e.g., collected or received) data. In some cases, a real-time event may occur nearly instantly or within a sufficiently short time period, for example, within at least 0.0001 milliseconds (ms), 0.0005 ms, 0.001 ms, 0.005 ms, 0.01 ms, 0.05 ms, 0.1 ms, 0.5 ms, 1 ms, 5 ms, 0.01 seconds, 0.05 seconds, 0.1 seconds, 0.5 seconds, 1 second, or more. In some cases, a real-time event may be executed almost instantly or within a sufficiently short time, for example, within up to 1 second, 0.5 seconds, 0.1 seconds, 0.05 seconds, 0.01 seconds, 5 ms, 1 ms, 0.5 ms, 0.1 ms, 0.05 ms, 0.01 ms, 0.005 ms, 0.001 ms, 0.0005 ms, 0.0001 ms, or less.

[0087] The terms "at least one of A and B" and "at least one of A or B" can be understood to mean A only, B only, or both A and B. The term "A and / or B" can be understood to mean A only, B only, or both A and B.

[0088] The terms "decompose," "dissociate," "reform," "crack," and "chemically transform" and grammatical variations thereof can be construed interchangeably. For example, the expression "decomposition of ammonia" can be interchangeably used with "dissociation of ammonia," "reformation of ammonia," "cracking of ammonia," "conversion of ammonia," and the like.

[0089] The terms "ammonia conversion" and "ammonia conversion efficiency" and grammatical variations thereof can be interpreted as the percentage of ammonia that is converted to hydrogen and nitrogen and can be interpreted interchangeably. For example, 90% "ammonia conversion", or "ammonia conversion efficiency" can represent that 90% of the ammonia is converted to hydrogen and nitrogen.

[0090] The term "turnover frequency" refers to the normalized ammonia consumption or hydrogen production (amount) per unit time per unit catalyst. アンモニアまたは水素 amount cat -1 time -1 ) or the forward reaction rate of ammonia decomposition. アンモニアまたは水素 is mmol アンモニアまたは水素 , mol アンモニアまたは水素 , g アンモニアまたは水素 , or mL アンモニアまたは水素 It may be measured as the amount cat is g cat , g 活性金属 , g 表面活性金属 , g 活性サイト , mol cat , mol 活性金属 , mol 表面活性金属 , or mol 活性サイト Time may be measured in seconds, minutes, hours, or days.

[0091] In some cases, the term "turnover frequency" refers to the normalized ammonia consumption or hydrogen production (amount) per unit time and per unit catalyst. アンモニアまたは水素 amount cat -1 time -1 ) may be interpreted as the effective reaction rate of ammonia decomposition (i.e., forward reaction minus reverse reaction). アンモニアまたは水素 is mmol アンモニアまたは水素 , mol アンモニアまたは水素 , g アンモニアまたは水素 , or mL アンモニアまたは水素 It may be measured as the amount cat is gcat , g 活性金属 , g 表面活性金属 , g 活性サイト , mol cat , mol 活性金属 , mol 表面活性金属 , or mol 活性サイト Time may be measured in seconds, minutes, hours, or days.

[0092] The terms "production rate" and "consumption rate" may be interpreted as the amount of a compound produced or consumed that is involved in a reaction, measured as net rate = forward reaction - reverse reaction. The units of "production rate" and "consumption rate" are units of mass. アンモニアまたは水素 amount cat -1 time -1 It can be said that the amount アンモニアまたは水素 is mmol アンモニアまたは水素 , mol アンモニアまたは水素 , g アンモニアまたは水素 , or mL アンモニアまたは水素 It may be measured as the amount cat is g cat , g 活性金属 , g 表面活性金属 , g 活性サイト , mol cat , mol 活性金属 , mol 表面活性金属 , or mol 活性サイト Time may be measured in seconds, minutes, hours, or days.

[0093] Reactor

[0094] In one aspect, the present disclosure provides a system for processing a source material. The system may include a reactor or reformer. The reactor or reformer may include one or more catalysts. The one or more catalysts may be used to process the source material. The one or more catalysts may be optimized to improve processing of the source material. The source material may include, for example, ammonia (NH3). The source material may be processed to generate a fuel source. The fuel source may include, for example, hydrogen and / or nitrogen. The fuel source may be provided to one or more hydrogen fuel cells, which may be configured to generate electrical energy using the fuel source. Such electrical energy may be used to power various systems, vehicles, and / or devices.

[0095] FIG. 1 generally illustrates a block diagram of an exemplary method for processing a source material to produce electrical energy. A source material 110 can be provided to a reactor 120. The source material 110 may include a compound that includes one or more hydrogen molecules. The compound may be, for example, ammonia or NH3. In some cases, the compound may be a hydrocarbon C x H y The raw material 110 may include, but is not limited to, hydrogen and / or nitrogen. The fuel source 130 may be provided to one or more fuel cells or one or more combustion engines to generate electrical energy or mechanical work. Such electrical energy may be used to power a variety of systems, vehicles, and / or devices, including, for example, land, air, or underwater vehicles.

[0096] As described above, one or more fuel cells can be used to generate electrical energy from a fuel source 130, which may include, but is not limited to, hydrogen and / or nitrogen. In some cases, the one or more fuel cells can generate electricity by an electrochemical reaction between fuels. The fuel may include hydrogen and / or nitrogen in the fuel source 130. The electricity generated by the fuel cells can be used to power one or more systems, vehicles, or devices. In some embodiments, excess electricity generated by the fuel cells may be stored in one or more energy storage units (e.g., batteries) for future use. In some optional embodiments, the fuel cells may be provided as part of a larger fuel cell system. The fuel cell system may include an electrolysis module. Electrolysis of a by-product (e.g., water) of one or more fuel cells can allow the by-product to be removed by breaking it down into one or more components (e.g., oxygen and / or hydrogen). Electrolysis of the by-product can also generate another fuel (e.g., hydrogen) for the fuel cells.

[0097] As described above, one or more combustion engines can be used to generate electrical energy or mechanical work from a fuel source 130, which may include, but is not limited to, hydrogen and / or nitrogen. In some cases, the one or more combustion engines can further include generating mechanical work by combustion of one or more fuels. The mechanical work can be converted to electrical energy by one or more generators. The fuel may include hydrogen and / or nitrogen in the fuel source 130. The electricity or mechanical work generated by the combustion engine can be used to power one or more systems, vehicles, or devices. In some embodiments, excess electricity or mechanical work generated by the combustion engine can be stored in one or more energy storage units (e.g., batteries) for future use. In some optional embodiments, the combustion engine may be provided as part of a larger engine or power generation system. The combustion engine system may include a combustion chamber. Electrolysis of a by-product (e.g., water) of one or more combustion engines can allow the by-product to be removed, for example, by breaking it down into one or more components (e.g., oxygen and / or hydrogen). Electrolysis of the by-product can also generate another fuel (e.g., hydrogen) for the combustion engine.

[0098] FIG. 2 illustrates a schematic of an exemplary method of hydrogen storage using liquid chemicals, according to some embodiments. Hydrogen can be stored using one or more liquid chemicals, whether produced by electrolysis of renewable energy or by hydrocarbon reforming. In some non-limiting embodiments, the one or more liquid chemicals may include, for example, ammonia, liquid organic hydrogen carriers (LOHC), formic acid (HCOOH), or methanol (CHOH). Hydrogen may be stored in a hydrogen-rich or hydrogen-lean form. The one or more liquid chemicals containing hydrogen can be processed as described elsewhere herein to release the hydrogen stored in the liquid chemicals. Once released, the hydrogen may be used for power generation (e.g., stationary or portable power generation) or may be supplied to a hydrogen fueling station or hydrogen supply facility.

[0099] In some cases, ammonia may be used as a hydrogen carrier. The hydrogen carrier may include a fluid or liquid chemical that can be used to store hydrogen. The use of ammonia as an energy carrier provides the advantages of hydrogen fuel (e.g., environmentally safe and high gravimetric energy density) when ammonia is decomposed into hydrogen, taking advantage of (a) the large volumetric density of ammonia compared to both gaseous and liquid hydrogen, and (b) the ability to transport ammonia at standard temperatures and pressures without the need for complex, high-pressure storage vessels typically used to store and transport hydrogen.

[0100] In some cases, hydrogenation can be used to store hydrogen in one or more fluid or liquid chemicals (e.g., ammonia). Hydrogenation can refer to treating a material or substance with molecular hydrogen (H2) to add one or more pairs of hydrogen atoms to various constituent compounds (e.g., one or more unsaturated compounds) that make up the material or substance. Hydrogenation can be carried out using a catalyst that can allow the reaction to occur under normal conditions of temperature and / or pressure. In some cases, the Haber-Bosch process (an artificial nitrogen fixation process) can be used to make ammonia. The process can be used to convert atmospheric nitrogen (N2) to ammonia (NH3) by reaction with hydrogen (e.g., H2 made or obtained by electrolysis) using metal catalysts under various reaction temperatures and pressures. 2NH3⇔N2+3H2

[0101] As described above, the Haber-Bosch process can be used to make ammonia that can be used as a hydrogen carrier. Using ammonia as a hydrogen carrier can provide several advantages, including easy storage at relatively standard conditions (0.8 MPa in liquid state, 20°C), and convenient transportation. Ammonia also has a relatively high hydrogen content (17.7% by weight, 120 grams of H2 per liter of liquid ammonia). Furthermore, the production of ammonia using the Haber-Bosch process can be powered by renewable energy sources (e.g., photovoltaic or solar thermal), making the production process environmentally safe and friendly, since N2 is the only by-product and there is no further emission of CO2. Once ammonia is produced, it can be processed (e.g., decomposed using a catalyst) to release hydrogen by a dehydrogenation process. The released hydrogen can then be fed to one or more fuel cells, such as a proton exchange membrane fuel cell (PEMFC) with a proton-conducting polymer electrolyte membrane, a polymer electrolyte membrane (PEM) fuel cell, a solid oxide fuel cell (SOFC), or one or more combustion engines with one or more combustion chambers. PEMFCs can have a relatively low operating temperature and / or pressure range (e.g., about 50-100°C). Proton exchange membrane fuel cells can be used to convert chemical energy released during electrochemical reactions of hydrogen and oxygen into electrical energy to create thermal energy, as opposed to direct combustion of hydrogen and oxygen gases. PEMFCs can operate on the opposite principle to PEM electrolysis, which produces electricity and consumes electricity. Combustion engines can produce mechanical work or electricity by combustion of (i) hydrogen and oxygen gases, or (ii) hydrogen, ammonia, and oxygen gases. The methods and systems disclosed herein may be implemented to achieve thermally efficient hydrogen production and may be extended for application to high energy density power systems.

[0102] FIG. 3 illustrates a schematic of a hydrogen extraction reactor 300 for extracting hydrogen from ammonia. Extraction of hydrogen from ammonia can be accomplished using one or more catalysts 340. The one or more catalysts 340 can include a heterogeneous catalyst. A heterogeneous catalyst may include a catalyst having a phase that is different from the phase of the reactants 310 (e.g., NH3) or the products 320 and / or 330 (N2 and / or H2). The one or more catalysts 340 can include a plurality of metal nanoparticles 350 incorporated on, within, or within a support material 360 (e.g., a composite support and / or catalyst support described elsewhere herein). Impregnation of the metal nanoparticles 350 within, within, or within the support material 360 can lower the activation energy barrier of the ammonia decomposition reaction, thereby enabling the one or more catalysts 340 to efficiently crack or decompose ammonia at a lower reaction temperature.

[0103] FIG. 4 illustrates, in a schematic manner, various types of modifications and / or treatments to optimize catalytic materials that can be used to crack ammonia. The catalyst may include any metal alloy, including, for example, nickel, chromium, iron, and / or aluminum, i.e., Ni / Cr-X, Ni / Cr-X / Al-Y, and / or Ni / Fe-X / Cr-Y / Al-Z, where X, Y, and / or Z range from 0 to 100. The surface of the catalyst may be treated (e.g., by etching, alloying, leaching, and / or using one or more acid treatments) to increase the surface area and improve the surface properties of the catalytic material. The catalyst may also undergo a catalyst coating step (e.g., by impregnation, physical vapor deposition (PVD), or chemical vapor deposition (CVD)) and / or one or more heat treatment steps. In some cases, the treated catalytic material may include a catalyst coating material that includes one or more electrical resistive catalysts.

[0104] In some embodiments, the catalyst may include one or more metal foam catalysts. The one or more catalysts may include, for example, modified metal foam catalysts. The catalyst material may be or may be subject to one or more modifications and / or treatments as shown and described elsewhere herein. In some cases, the catalyst may include nickel chromium aluminum (NiCrAl) foam.

[0105] In some cases, at least one of the first catalyst and the second catalyst can include a metal foam catalyst. The metal foam catalyst can include nickel, iron, chromium, and / or aluminum. In some cases, the metal foam catalyst can include one or more alloys including nickel, iron, chromium, and / or aluminum.

[0106] In some embodiments, the metal foam catalyst may include a catalytic coating of one or more powdered or pelleted catalysts. The catalytic coating may include a metallic material, a promoter material, and / or a support material. The metallic material may include, for example, ruthenium, nickel, rhodium, iridium, cobalt, molybdenum, iron, platinum, chromium, palladium, and / or copper. The promoter material may include, for example, sodium, potassium, rubidium, and / or cesium. In some cases, the support material may include, for example, at least one of Al2O3, MgO, CeO2, SiO2, TiO2, Y2O3, ZrO2, SiC, silicon nitride (SiN), MgAl2O4, CaAl2O4, CoAl2O4, hexagonal boron nitride, one or more boron nitride nanotubes, and / or one or more carbon nanotubes. In some cases, the support material may include, for example, ... x O y , Mg x O y , Ce x O y , Si x O y , Ti x O y , Y x Oy , Zr x O y , B x N y , Si x C y , Si x N y and / or C. In some embodiments, the catalytic coating may include one or more ruthenium-based precursors. The one or more ruthenium-based precursors may be, for example, RuCl3, Ru(NO)(NO3)3, or Ru3(CO). 12 In any of the embodiments described herein, the metal foam catalyst may have an apparent electrical resistivity of at least about 8 microohm-meters (μΩm).

[0107] In some cases, the metal foam catalyst may be treated using one or more of etching, alloying, leaching, or acid treatment to increase the surface area of ​​the metal foam catalyst. In some cases, the metal foam catalyst may be heat treated. In some cases, the metal foam catalyst may be coated using physical vapor deposition (PVD) and / or chemical vapor deposition (CVD) processes.

[0108] In some embodiments, the one or more ammonia decomposition catalysts may include a metallic material, a promoter material, and / or a support material. In some cases, the metallic material may include, for example, at least one of ruthenium, nickel, rhodium, iridium, cobalt, molybdenum, iron, platinum, chromium, palladium, and / or copper. In some cases, the promoter material may include, for example, at least one of sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, and / or barium. In some cases, the support material may include, for example, at least one of Al. x O y , Mg x O y , Ce x O y , Si x O y , Ti x Oy , Y x O y , Zr x O y , B x N y , Si x C y , Si x N y , and / or C. In some cases, the support material may include at least one of, for example, Al2O3, MgO, CeO2, SiO2, SiC, TiO2, Y2O3, ZrO2, SiN, MgAl2O4, CaAl2O4, CoAl2O4, hexagonal boron nitride, one or more boron nitride nanotubes, and / or one or more carbon nanotubes.

[0109] Active Metal Nanoparticles

[0110] The one or more nanoparticles may be used to decompose ammonia. The one or more nanoparticles may include an active metal configured to decompose or facilitate the decomposition of ammonia. In some cases, the active metal nanoparticles may include, for example, ruthenium (Ru). The nanoparticles may include one or more binding sites (also referred to herein as active sites) for ammonia to attach to. The binding sites may be determined based on the shape, morphology, and / or surface chemistry or properties of the active metal nanoparticles. As described elsewhere herein, the morphology of the active metal nanoparticles may correspond to the size, shape, pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure of the one or more active metal nanoparticles. As described elsewhere herein, the physical or chemical properties of the active metal nanoparticles may include the Arrhenius acidity or basicity, Lewis acidity or basicity, electron density, electronic state, or hydrophilicity or hydrophobicity of the one or more active metal nanoparticles. The one or more ammonia particles may attach to the binding sites of the active metal nanoparticles. The active metal nanoparticles can be configured to cleave the nitrogen-hydrogen (NH) bond of ammonia. The morphology and / or surface chemistry or properties of the active metal nanoparticles can enhance the adsorption of ammonia, the decomposition (or cleavage) of the NH bond, and the desorption of hydrogen and / or nitrogen.

[0111] form

[0112] The morphology of the nanoparticles can be optimized. The morphology can include the structure, size, aspect ratio, facet distribution, and / or shape of the nanoparticles. In some cases, the morphology may include the grain structure, particle size, and / or grain boundaries. In some cases, the morphology can correspond to the size, shape, pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, particle size, grain shape, crystal structure, flake size, or layered structure of one or more active metal nanoparticles. The morphology of the nanoparticles can be customized or modified to optimize the location and / or availability of active sites at the molecular level. The binding sites or active sites of the nanoparticles may be defined or determined in part based on the morphology of the nanoparticles.

[0113] surface chemistry

[0114] The chemical and / or physical properties of the nanoparticles can be optimized. The chemical and / or physical properties can include, for example, the surface chemistry or properties of the one or more active metal nanoparticles. The physical and / or chemical properties of the active metal nanoparticles can include, for example, the Arrhenius acidity or basicity, Lewis acidity or basicity, electron density, electronic state, or hydrophilicity or hydrophobicity of the one or more active metal nanoparticles. The surface chemistry or properties of the nanoparticles can be customized or altered to optimize the location and / or availability of the active sites at the molecular level. The binding sites or active sites of the nanoparticles can be defined or determined in part based on the surface chemistry or properties of the nanoparticles.

[0115] shape

[0116] In some embodiments, the catalyst support material can include a porous material. In some embodiments, the catalyst support material can include a two-dimensional material. In some embodiments, the catalyst can be provided as a coating on a bead or pellet. This can solve the problem of compressing a powder catalyst into a bead or pellet shape, but not being able to use all of the catalyst material within the body of the bead or pellet. In some embodiments, the catalyst can be provided as a coating on a powder. In some cases, the catalyst can be provided as a coating on a porous monolith or solid foam material. The coating can be optimized with a predetermined amount of catalyst material to ensure that at least a threshold amount of catalyst material is used. The threshold amount can be, for example, at least about 90% by weight or volume. A plurality of beads or pellets with a coating of catalyst material can be used in combination with a reactor or reformer to decompose or crack ammonia to produce hydrogen.

[0117] 5 and 6 illustrate schematics of an exemplary process for modifying and improving a catalyst support. A catalyst support may be provided. The catalyst support may include any one or more metals (e.g., aluminum), non-metals, and / or metalloids. In some cases, the pores of the catalyst support material may be optimized. Optimizing the pores may include, for example, optimizing the pore size, pore density, pore volume, or the location or distribution of the pores across the area or volume of the catalyst support material. The pores may be modified chemically (e.g., using corrosive gases or liquid chemicals to selectively etch the pores) or physically (e.g., using one or more heat treatments under different gases). In some cases, the heat treatment may change the phase or state of the catalyst support material, which may also change the pore size of the catalyst support material. In some cases, the pore size may be optimized separately for different types of reactions or different types of performance characteristics. In some cases, the heat treatment may involve exposing the catalyst support material to one or more reactive gases. In some cases, the reactive gas may include a gas containing one or more of nitrogen (e.g., NO, NO2, NH3, HCN), sulfur (H2S, SO2), chlorine (Cl2, HCl), carbon (CO, CO2), fluorine, or a gas generated from a plasma, such as ozone.

[0118] In some embodiments, the surface of the catalyst support may be modified or coated. In some cases, the catalyst support material with optimized pore characteristics may be coated with an intermediate layer that can serve as a base for growing one or more active metals or active metal particles. When the active metal nanoparticles are provided on the intermediate layer, the intermediate layer can be used to change or affect the morphology of the active metal nanoparticles. In some cases, the intermediate layer may include a composite support material. The composite support material may be deposited on the catalyst support material using vapor deposition (e.g., chemical vapor deposition or physical vapor deposition). In some cases, the composite support material may be deposited on the catalyst support material by sputtering.

[0119] The composite support material can have morphology and physical or chemical properties (e.g., surface chemistry). The morphology and / or physical or chemical properties of the composite support material layer can be used to change or affect the morphology and physical or chemical properties of the active metal nanoparticles deposited on top of the composite support material. In some cases, the active metal nanoparticles can grow while following the morphology and physical or chemical properties of the composite support material layer.

[0120] In some cases, the catalyst support material can have a morphology and physical or chemical properties (e.g., surface chemistry). The morphology and / or physical or chemical properties of the catalyst support material layer can be used to change or affect the morphology and physical or chemical properties of the active metal nanoparticles deposited on top of the catalyst support material or composite support material. In some cases, the active metal nanoparticles can grow following the morphology and physical or chemical properties of the catalyst support material and / or composite support material layer.

[0121] In some cases, the catalyst support may have one or more properties or characteristics that can be optimized using one or more physical or chemical processes. The one or more properties or characteristics may include, for example, the morphology or surface chemistry or characteristics of the catalyst support. The morphology may include pore structure, pore size, pore shape, pore volume, pore density, pore size distribution, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure. The surface chemistry or characteristics may include Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, or hydrophilicity or hydrophobicity. In some cases, the morphology or surface chemistry or characteristics of the composite support material may follow the morphology or surface chemistry or characteristics of the catalyst support. In some cases, the morphology or surface chemistry or characteristics of the active metal nanoparticles may follow the morphology or surface chemistry or characteristics of the catalyst support material and / or the composite support material. In some cases, the morphology or surface chemistry or characteristics of the composite support material may follow the morphology or surface chemistry or characteristics of the catalyst support material.

[0122] In some cases, CVD can be used to deposit a composite support material including boron nitride onto a catalyst support. A thin layer of the composite support material may be deposited onto a surface layer of the catalyst support. CVD can be used to form a network of the composite support material on an existing catalyst support and / or within one or more pores of the catalyst support material. In some cases, the composite support material may include various metal oxides (e.g., titanium oxide, or one or more other two-dimensional (2D) or three-dimensional (3D) materials).

[0123] Depositing the composite support material as a separate layer on top of the catalyst support may be advantageous over using the composite support material in powder form, as the powder form may be difficult to use in the reactor due to the resulting pressure drop. Compressing the powder into a pellet shape may solve the pressure drop problem, but the composite support material within the body of the pellet may not be fully utilized, which is wasteful and inefficient. In some cases, powder may refer to a granular material in which the majority of the particles are sized less than 1 mm in dimension. In some cases, the majority may be at least about 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, 99% by weight, volume, or count.

[0124] After the composite support material is deposited on the catalyst support material, one or more active metals can be deposited on the catalyst support material and / or the composite support material. The active metal may be deposited using CVD. The active metal can be deposited as active metal nanoparticles on top of the composite support and also in one or more modified pores of the catalyst support material. This may facilitate the decomposition of any ammonia molecules passing through the pores of the catalyst support. The deposition of active metal nanoparticles on the composite support may also be referred to herein as impregnation of the composite support with one or more active metal nanoparticles.

[0125] When the active metal nanoparticles are deposited on or in the catalyst support material and / or composite support material, they can grow according to the morphology and / or physical or chemical properties of the composite support material. In some cases, the composite support material may include hexagonal particles. The active metal nanoparticles can grow while maintaining a particle shape corresponding to the particle shape of the composite support material. In some cases, the active metal nanoparticles can grow while maintaining a hexagonal particle shape. The composite support material can provide a 2D structure or base for ruthenium growth. The ruthenium can grow while following the structure of the composite support material. In some cases, the composite support material may include boron nitride. The ruthenium can grow while maintaining the hexagonal morphology of the composite support material. In some cases, the catalyst can undergo one or more heat treatments under vacuum conditions and / or in the presence of various gases, such as hydrogen gas or ambient air. Such heat treatments are used to thermally activate the active metal nanoparticles incorporated in the composite support structure and promote a change in the morphology and / or physical or chemical properties of the active metal nanoparticles to follow the morphology and / or physical or chemical properties of the materials or particles (e.g., atoms or molecules) that make up the composite support.

[0126] In some cases, the composite material and / or one or more active metal nanoparticles incorporated therein can be promoted (e.g., with cesium) to change the electronic state or electron density of the active metal nanoparticle. As noted above, the active metal nanoparticle may include, for example, ruthenium. In some cases, the altered electronic state or electron density can promote the detachment of recombined nitrogen and / or the cleavage of N-H bonds during the ammonia decomposition reaction.

[0127] The methods and processes for producing composite catalysts disclosed herein can be implemented to produce catalysts with one or more desirable properties or performance characteristics (e.g., efficient hydrogen production). The catalysts can lower the activation energy barrier for the ammonia decomposition reaction, promoting the reaction at lower temperatures while increasing throughput and improving the efficient utilization of precious metals. The methods and processes disclosed herein can be adapted and expanded for economical mass production of high performance, high efficiency catalysts.

[0128] FIG. 7 illustrates an exemplary method for synthesizing one or more active metal nanoparticles. In some cases, the active metal nanoparticles may be produced from a precursor material (e.g., a precursor material that includes ruthenium). The active metal nanoparticles may be promoted with one or more alkali metals. The promoter may include one or more substances (e.g., cocatalysts) that can be added to enhance ammonia conversion efficiency or selectivity. The active metal nanoparticles may undergo one or more heat treatments to thermally activate the active metal nanoparticles such that the active metal nanoparticles grow and change in morphology or physical / chemical properties to reflect the morphology and / or physical or chemical properties of the composite support material in or on which the active metal nanoparticles are deposited. The methods described herein can be used to control the morphology, surface chemistry, and / or dispersion of the active metal nanoparticles and to control the interactions between the active metal nanoparticles and the composite or catalytic support. The methods of the present disclosure can also be used to optimize one or more active sites on the active metal nanoparticles for chemically transforming, decomposing, or cracking one or more ammonia molecules.

[0129] The optimized catalysts described herein can exhibit improved ammonia decomposition performance and increased ammonia conversion efficiency. The ammonia conversion efficiency of the optimized catalysts can be a function of reaction temperature. In some cases, the ammonia conversion efficiency can reach at least about 90% at a reaction temperature of about 500 degrees Celsius. In some cases, the ammonia conversion efficiency can range from about 70% to about 99% at a reaction temperature ranging from about 300 degrees Celsius to about 600 degrees Celsius or higher.

[0130] In some embodiments, the catalyst preparation method may include a heat treatment under a reactive gas. Such a heat treatment may be used to modify the porosity of the support for optimized mass transfer. Also, such a heat treatment may be used to modify one or more properties of the support (e.g., the basicity or acidity of the support) for better surface modification results.

[0131] In some embodiments, the catalyst manufacturing method may include a surface modification and coating step. The surface modification and coating step may include deposition of an intermediate layer by PVD or CVD. PVD or CVD may be used to coat the support features with a thin, uniform layer of the functional material. The coating layer may have a thickness ranging from at least about 1 nanometer to about 20 nanometers or more. The functional material serves as a substrate for nanoparticle growth. In some cases, the morphology and / or physical or chemical properties of the functional material may affect the growth and / or morphology or surface chemistry of the nanoparticles.

[0132] In some embodiments, the catalyst preparation method may include impregnation of active metal nanoparticles. Impregnation may include precursor impregnation by vacuum deposition or incipient wetness impregnation. This may allow for control of the precursor immobilized on the functional material.

[0133] In some embodiments, the method of making the catalyst may include promoting thermal, physical, chemical, or electrochemical activation. Promoting may include impregnating promoter materials (e.g., alkali metals and / or alkaline earth metals) into the active metal and / or composite support material to promote modification of the electron density and modification or optimization of the morphology or active sites of the catalyst. Thermal and / or chemical activation may also be used to modify the morphology of the active metal nanoparticles in a reducing environment (e.g., an environment including hydrogen gas) or in the presence of one or more noble gases.

[0134] FIG. 8A illustrates a schematic of the effect of catalyst reduction on ammonia conversion efficiency according to some embodiments of the present disclosure. The catalysts of the present disclosure may be appropriately doped, promoted and / or heat treated to optimize catalytic performance and ammonia conversion efficiency. Compared to bare sample catalysts (i.e., catalysts that have not been subjected to doping, promotion and / or heat treatment), the doped, promoted and heat treated catalysts may exhibit higher ammonia conversion efficiency. Higher temperatures or treatment times may result in better performance of the catalyst. For example, bare sample catalysts may exhibit up to about 30% ammonia conversion efficiency at a temperature of about 500° C., while doped, promoted and heat treated catalysts at 700° C. may exhibit at least about 60% or more ammonia conversion efficiency at a temperature of about 500° C. Furthermore, doped, promoted and heat treated catalysts at 900° C. may exhibit at least about 80% or more ammonia conversion efficiency at a temperature of about 500° C.

[0135] FIG. 8B illustrates a schematic of the effect of heat treating a catalyst on hydrogen production or production rate, according to some embodiments. In some cases, the hydrogen production rate of a catalyst can be increased by at least about two-fold or more with a suitable heat treatment. For example, a bare untreated catalyst can have a hydrogen production rate of less than about 125 mmol of hydrogen per gram of catalytic material per hour. A doped catalyst can have a hydrogen production rate of about 150 mmol of hydrogen per gram of catalytic material per hour. A catalyst that has been heat treated under ammonia can have a hydrogen production rate of more than about 150 mmol of hydrogen per gram of catalytic material per hour. A catalyst that has been heat treated under hydrogen at about 700° C. for about 20 hours can have a hydrogen production rate of at least about 175 mmol of hydrogen per gram of catalytic material per hour. A catalyst that has been heat treated under hydrogen at about 700° C. for about 40 hours can have a hydrogen production rate of at least about 200 mmol of hydrogen per gram of catalytic material per hour. A catalyst subjected to heat treatment under hydrogen at about 900° C. for about 9 hours can have a hydrogen production rate of at least about 250 mmol of hydrogen per gram of catalyst material per hour.

[0136] FIG. 8C illustrates the effect of catalyst active metal promotion on ammonia conversion efficiency according to some embodiments of the present disclosure. The catalysts of the present disclosure can be promoted with one or more alkali metals. In some cases, cesium can be one of the most effective promoters for X-Al2O3 catalysts. However, in some cases, excessive promoter incorporation can decrease catalytic performance and hydrogen production or production rate. Thus, there is an optimal promoter amount for a catalytic material. The catalysts of the present disclosure may be appropriately doped, promoted and / or heat treated to optimize catalytic performance and hydrogen production or production rate.

[0137] In some cases, bare sample catalysts may exhibit an ammonia conversion efficiency of up to about 20% at a temperature of about 500° C. Potassium promoted catalysts may exhibit an ammonia conversion efficiency of at least about 60% or greater at a temperature of about 500° C. Cesium promoted catalysts may exhibit an ammonia conversion efficiency of at least about 85% or greater at a temperature of about 500° C.

[0138] 8D and 8E each illustrate a schematic of the effect of doping a catalyst on ammonia conversion efficiency and hydrogen production or production rate, according to some embodiments. In some cases, a catalyst with an optimal concentration of promoter may exhibit an ammonia conversion efficiency of at least about 85% or more at a temperature of about 500° C. On the other hand, a catalyst having a promoter concentration less than or in excess of the optimal promoter concentration may exhibit a lower ammonia conversion efficiency (e.g., about 20% to about 60% or less).

[0139] As shown in FIG. 8E, the amount of promoter may also affect the hydrogen production or production rate. For example, a catalyst without a promoter may have a hydrogen production rate of up to about 175 mmol of hydrogen per gram of catalytic material per hour. When the molar ratio of active metal to promoter material is about 1:1 (e.g., 1:1 for ruthenium to cesium), the hydrogen production rate may be up to at least about 300 mmol of hydrogen per gram of catalytic material per hour. When the molar ratio of active metal to promoter material is about 1:3 (e.g., 1:3 for ruthenium to cesium), the hydrogen production rate may be up to at least about 450 mmol of hydrogen per gram of catalytic material per hour. As described elsewhere herein, a catalyst with a molar ratio of active metal to promoter material of about 1:3 (e.g., 1:3 for ruthenium to cesium) may exhibit even higher hydrogen production or production rates (e.g., at least about 500 mmol of hydrogen per gram of catalytic material per hour) when subjected to one or more heat treatments. However, if the molar ratio of active metal to promoter material is increased excessively to about 1:6 (e.g., 1:6 for ruthenium to cesium), the hydrogen production rate may decrease to less than about 100 mmol of hydrogen per gram of catalyst material per hour.

[0140] material

[0141] In any of the embodiments described herein, the catalyst support material may include, for example, a metal oxide-based support with one or more micropores or mesopores. In some cases, the support material may include, for example, aluminum oxide (Al2O3) or nickel (Ni)-based metal foam. In some embodiments, the catalyst support material may include one or more of aluminum oxide (Al2O3), magnesium oxide (MgO), cerium dioxide (CeO2), silicon dioxide (SiO2), silicon carbide (SiC), yttrium oxide (Y2O3), one or more zeolites (e.g., MFI zeolite, MCM-41 zeolite, Y-type zeolite, X-type zeolite), titanium dioxide (TiO2), zirconium dioxide (ZrO2), lanthanum oxide (La2O3), or chromium oxide (Cr2O3). In some embodiments, the catalyst support material may include, for example, aluminum oxide (Al2O3), magnesium oxide (MgO), cerium dioxide (CeO2), silicon dioxide (SiO2), silicon carbide (SiC), yttrium oxide (Y2O3), one or more zeolites (e.g., MFI zeolite, MCM-41 zeolite, Y-type zeolite, X-type zeolite), titanium dioxide (TiO2), zirconium dioxide (ZrO2), lanthanum oxide (La2O3), or chromium oxide (Cr2O3). x O y , Mg x O y , Ce x O y、 S x O y , Y x O y , Ti x O y , Zr x O y , La x O y , or Cr x O y may include one or more of:

[0142] In any of the embodiments described herein, the composite coating material includes a carbon-based material, a boron-based material, or a metal oxide. The carbon-based material may include, for example, activated carbon (AC), one or more carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene oxide (GO), graphite, one or more carbon nanoribbons, or reduced graphene oxide (rGO). The boron-based material may include, for example, hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs). The metal oxide may include, for example, TiO2, MgO, La2O3, CeO2, Y2O3, one or more CeO2 nanotubes, nanorods, or nanocubes, mesoporous silica (e.g., KIT-6), or ZrO2.

[0143] In any of the embodiments described herein, the active metal or active metal nanoparticles may include, for example, ruthenium (Ru), nickel (Ni), cobalt (Co), iron (Fe), copper (Cu), molybdenum (Mo), iridium (Ir), rhenium (Re), platinum (Pt), or palladium (Pd). The active metal or metals can be produced from one or more precursor materials. Precursor materials include, for example, ruthenium chloride (RuCl3), ruthenium nitrosyl nitrate (Ru(NO)(NO3)3), triruthenium dodecacarbonyl (Ru3(CO) 12 ), ruthenium acetylacetonate (Ru(acac)3), ruthenium nitrate (Ru(NO3)3), hexaammineruthenium chloride (Ru(NH3)6Cl3), cyclohexadiene ruthenium tricarbonyl (CHD)Ru(CO)3), butadiene ruthenium tricarbonyl ((BD)Ru(CO)3), or dimethylbutadiene ruthenium tricarbonyl ((DMBD)Ru(CO)3).

[0144] As mentioned above, in some cases, one or more promoters or promoters can be used to modify or improve the electron density of the active metal nanoparticles and / or composite support materials. In any of the embodiments described herein, the one or more promoters or promoters may include, for example, cesium (Cs), rubidium (Rb), potassium (K), sodium (Na), barium (Ba), strontium (Sr), calcium (Ca), or magnesium (Mg). In some cases, excessive concentrations of promoter materials can reduce catalytic performance and ammonia conversion efficiency (i.e., there is an optimum amount of doping material). As mentioned above, one or more promoters can be added to the catalyst of the present disclosure in a suitable amount or relative concentration to optimize catalytic performance and ammonia conversion efficiency.

[0145] In some embodiments, one or more layers of a composite material may be coated on a catalyst support material. The composite material may comprise one or more layers of boron nitride. The one or more layers may have a thickness of up to about 10 nanometers.

[0146] In some embodiments, the catalyst support comprising a layer of composite material deposited on the catalyst support may be impregnated with one or more active metal nanoparticles. In some cases, the active metal nanoparticles may be deposited on the composite layer and the morphology of the active metal nanoparticles may be modified by treating the nanoparticles with one or more heat treatment methods. In some cases, the nanoparticles may have a size ranging from about 1 nanometer to about 50 nanometers. In some cases, the dispersion of the nanoparticles may range from about 10% to about 60%. As used herein, dispersion can refer to the number of active metal atoms exposed on the surface of the active metal nanoparticles relative to the total number of atoms that make up the catalyst or the surface area or volume of the catalyst. The active metal atoms exposed on the surface of the catalyst can bind with one or more ammonia molecules using one or more active sites (also referred to herein as binding sites) of the active metal nanoparticles. As described elsewhere herein, the active sites or binding sites of the active metal nanoparticles can be optimized by subjecting the active metal nanoparticles to one or more heat treatments that allow the active metal nanoparticles to assume the morphology of the particles that make up the composite layer.

[0147] In some embodiments, the optimized catalyst disclosed herein can have a higher hydrogen production rate than that of a conventional ruthenium catalyst. The hydrogen production rate based on the active metal content of the optimized catalyst can be at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 times or more greater than that of a conventional catalyst. In some cases, the optimized catalyst can exhibit an ammonia to hydrogen conversion efficiency of at least about 90% at 450°C and a gas hourly space velocity (GHSV) of less than 10 liters / hour per gram of catalyst. In some cases, the optimized catalyst can exhibit a lower nitrogen desorption activation energy than a conventional ruthenium catalyst.

[0148] FIG. 9 illustrates a schematic of a system for mass production of optimized catalysts. The system may include a reaction chamber including a furnace and a rotatable chamber for housing one or more catalyst supports. The rotatable chamber may be configured for CVD (e.g., CVD of a composite material on the catalyst support and / or CVD of one or more active metals on the composite layer and / or catalyst support). The one or more catalyst supports may be processed in the reaction chamber to produce an optimized or modified catalyst as described elsewhere herein. CVD may occur as the rotatable chamber rotates, thereby allowing the composite material or active metal to be deposited on various faces, portions, or surface regions of the catalyst support. The furnace may include one or more heating units configured to heat the one or more catalyst supports to optimize one or more porosity characteristics, morphology, and / or one or more physical or chemical properties of the one or more catalyst supports. In some cases, the one or more physical or chemical properties may include a surface chemistry or properties of the one or more catalyst supports. The morphology may include, for example, pore structure, pore shape, pore size distribution, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure. The surface chemistry or properties may include, for example, Arrhenius acidity or basicity, Lewis acidity or basicity, surface hydroxyl group density, or hydrophilicity or hydrophobicity. In some cases, the one or more heating units may be configured to heat the catalyst support comprising (i) the layer of the first precursor material and (ii) the layer of the second precursor material to thermally, physically, electrochemically, and / or chemically activate the one or more active metal nanoparticles to promote growth and changes in morphology and / or surface chemistry or properties of the nanoparticles.

[0149] The reaction chamber may be in fluid communication with a vacuum pump. The vacuum pump may be used to create a vacuum environment in the reaction chamber. The catalyst of the present disclosure may be produced in the vacuum environment created using the vacuum pump.

[0150] In some cases, the reaction chamber may be in fluid communication with a source of reactive gas. The reactive gas may be provided to the reaction chamber during one or more thermal treatments of the catalyst. In some cases, the reaction chamber may be in fluid communication with a source of hydrogen gas. The hydrogen gas may be provided to the reaction chamber during one or more thermal treatments of the catalyst. In some cases, the reaction chamber may be in fluid communication with a source of noble gas. The noble gas may be provided to the reaction chamber during one or more thermal treatments of the catalyst. The reactive gas, hydrogen gas, and / or noble gas may be provided to the reaction chamber simultaneously or at different periods or time frames. In some cases, the reactive gas may be provided at a first time point, the hydrogen gas may be provided at a second time point, and the noble gas may be provided at a third time point. The first, second, and third time points may correspond to different stages or steps of catalyst production or manufacturing. In some cases, the first, second, and third time points may correspond to different stages or steps of one or more thermal treatments of the catalyst. The flow of the reactant gas, hydrogen gas, and / or noble gas to the reaction chamber may be controlled using one or more mass flow controllers (MFCs). In some cases, the reactant gas may be provided to the reaction chamber at a first mass flow rate, the hydrogen gas may be provided to the reaction chamber at a second mass flow rate, and the noble gas may be provided to the reaction chamber at a third mass flow rate. The first, second, and third mass flow rates may be the same. Alternatively, the first, second, and third mass flow rates may be different.

[0151] In some embodiments, the reaction chamber may be in fluid communication with one or more sources of precursor material. The one or more sources of precursor material may include a first source of precursor material, a second source of precursor material, and a third source of precursor material. The first source of precursor material may include one or more materials for surface modification of the catalyst support. The first source of precursor material may include one or more composite support materials, for example, as described elsewhere herein. The second source of precursor material may include one or more materials for depositing metals on the catalyst support. The second source of precursor material may include, for example, one or more active metals or active metal nanoparticles, as described elsewhere herein. In some cases, the one or more active metal nanoparticles may be configured to grow according to the morphology and / or surface chemistry or properties of the first precursor material when thermally and / or chemically activated. The third source of precursor material may include one or more materials for doping or promotion. The third source of precursor material may include, for example, one or more dopant or promoter materials (e.g., alkali metals) for promoting modification of electron density, as described elsewhere herein. Doping or promoting may include impregnating the layer of the first precursor material, the layer of the second precursor material, or the one or more active metal nanoparticles with one or more dopants or promoters, respectively, to modify the morphology, modify the active sites, modify the electron density, and / or modify the electronic state.

[0152] In some cases, the morphology and / or surface chemistry or properties of the first precursor material may follow that of the one or more catalyst supports. In some cases, the morphology and / or surface chemistry or properties of the second precursor material may follow that of the one or more catalyst supports and / or the first precursor material.

[0153] In some embodiments, the system may include a heater for heating one or more sources of precursor material. The heater may or may not be in thermal communication with the reaction chamber. The heater may or may not be in thermal communication with a furnace of the reaction chamber. In some embodiments, the heater and / or furnace may include, for example, an electric heater and / or a fired heater.

[0154] In some cases, the system may be configured for mass production of various optimized or modified catalyst materials that can be used to perform efficient decomposition or cracking of ammonia. The system may allow all processes (e.g., thermal or chemical treatment of the catalyst support for pore modification, deposition of one or more layers of composite support material onto the catalyst support, impregnation of active metal nanoparticles, thermal treatment of the catalyst to optimize the morphology of the active metal nanoparticles, doping of the catalyst to optimize electron density, etc.) to occur simultaneously or near simultaneously. In some embodiments, the system may be configured for in-situ thermal treatment of catalyst or precursor materials.

[0155] In some cases, the rotatable reaction chamber may be configured to provide a reducing environment for thermal and / or chemical activation of the one or more active metal nanoparticles. The reducing environment may include, for example, hydrogen or ammonia gas, or one or more noble gases. In some cases, hydrogen gas and one or more noble gases can provide the reducing environment during thermal and / or chemical activation of the one or more active metal nanoparticles.

[0156] Reactor or reformer with optimized catalyst

[0157] The catalysts of the present disclosure can be compatible with various power systems (e.g., reactors or reformers) for the decomposition or cracking of ammonia to produce hydrogen. The power system may include, for example, a reactor or reformer that can perform catalytic decomposition or cracking of ammonia to extract and / or produce hydrogen. Such a reactor or reformer may be operated using thermal energy. In some cases, the power system may include a combustor that generates thermal energy to drive the operation of the reactor or reformer. In some cases, the thermal energy may be generated from the combustion of chemical compounds (e.g., hydrogen or hydrocarbons).

[0158] In some cases, the reactor or reformer may include an outlet configured to direct one or more fluids (e.g., ammonia, nitrogen, and / or hydrogen) to another system or subsystem. In some cases, the outlet may be configured to direct hydrogen gas produced by the reactor or reformer to one or more fuel cells and / or one or more combustion mechanisms. In some cases, the outlet may be configured to direct hydrogen gas produced by the reactor or reformer to one or more combustors to generate thermal energy that can be used to power or heat the reactor or reformer (e.g., for autothermal heating or self-heating). In some cases, the outlet may be configured to direct hydrogen, nitrogen, and / or ammonia to at least one other reactor or reformer (e.g., to combust hydrogen to heat at least one other reactor or reformer).

[0159] Hydrogen produced using the optimized catalyst of the present disclosure may be fed to one or more fuel cells or proton exchange membrane fuel cells (PEMFC) to generate electrical energy. Hydrogen produced using the optimized catalyst of the present disclosure may also be fed to one or more combustion engines to generate mechanical work or mechanical energy. Hydrogen produced and / or extracted using a reactor or reformer may be fed to one or more fuel cells or one or more combustion engines, which may generate electrical energy or mechanical work to power one or more systems, subsystems, or devices that require electrical or mechanical energy to operate. In some cases, at least a portion of the partially produced and / or extracted hydrogen and nitrogen from the reactor or reformer, as well as the residual ammonia mixture, may be fed to one or more other reactors or reformers to enable a continuous reforming process. The partially produced and / or extracted hydrogen and nitrogen, as well as the residual ammonia, may be part of a partially cracked ammonia stream. The partially cracked ammonia stream may be produced using a reactor or reformer having an ammonia conversion efficiency of less than 100%. The partially cracked stream may be sent to one or more downstream reactors or reformers to minimize waste and maximize the amount of ammonia that can be cracked or cracked. In some cases, hydrogen produced and / or extracted using the reactor or reformer may be fed to one or more other reactors or reformers. In such cases, the one or more other reactors or reformers may be configured to combust the hydrogen to generate additional thermal energy. Such additional thermal energy may be used to heat one or more other reactors or reformers to drive additional catalytic decomposition or cracking of ammonia to extract and / or produce additional hydrogen.

[0160] In some cases, the reactor or reformer can be configured to directly heat the optimized catalyst using resistive heating (e.g., by passing an electric current through the catalyst itself or through a catalyst support). In such cases, the reactor or reformer may include one or more electrodes to pass an electric current through the catalyst to heat the catalyst (e.g., by resistive heating or Joule heating). The one or more electrodes may include, for example, one or more copper electrodes. In other cases, the reactor or reformer may be configured to heat the optimized catalyst by burning hydrogen. The optimized catalyst can be configured to decompose ammonia into hydrogen and / or nitrogen when heated by combustion or resistive heating.

[0161] In some cases, the reactor or reformer may include one or more conductive springs. The one or more conductive springs may be provided adjacent to the optimized catalyst disclosed herein. In some cases, the one or more conductive springs may be provided at both ends of the catalyst. The one or more conductive springs may be in physical, electrical, and / or thermal communication with the catalyst, the catalyst bed, and / or one or more electrodes used to perform direct resistive heating of the catalyst. The one or more conductive springs may be configured to reduce thermal stress on the catalyst when the catalyst undergoes thermal cycling. The one or more conductive springs may be configured to accommodate thermal expansion during heating of the catalyst and thermal contraction during cooling of the catalyst. The one or more conductive springs may reduce and / or redistribute mechanical loads on the catalyst bed such that the catalyst bed can withstand multiple thermal cycles without breaking or fracturing. In some cases, the one or more springs may be configured to reduce thermal stress on the catalyst due to thermal expansion or contraction of the catalyst during one or more thermal cycling procedures. The one or more springs may include, for example, copper springs. The use of one or more conductive springs can enable the reactor or reformer to reduce or minimize thermal stress on the catalyst bed during rapid temperature changes, providing fast start-up capabilities.

[0162] Hybrid Heating

[0163] In some cases, the optimized catalyst may be hybrid heated in the reactor or reformer. Such hybrid heating can improve heat transfer while minimizing reactor heat loss and increasing start-up time. The hybrid heating design can also reduce the weight and volume of the reactor or reformer and provide an optimized heat source for ammonia conversion while improving the thermal management characteristics of the system.

[0164] In some cases, the optimized catalyst may be heated using one or more heat sources. In some cases, the one or more heat sources may comprise two or more heat sources or heating units. In some cases, the two or more heat sources may be the same or similar. In other cases, the two or more heat sources may be different. For example, a first heat source may be configured for Joule heating and a second heat source may be configured for combustion.

[0165] In some embodiments, the optimized catalyst may be heated using multiple heating units. The multiple heating units may include a first heating unit configured to heat at least a first portion of the catalyst by burning hydrogen and a second heating unit configured to heat at least a second portion of the catalyst using electrical heating. As used herein, the term "electrical heating" generally refers to heating that is performed at least in part by passing electrons through a material (e.g., a conduit). The conduit may be a resistive load. In some examples, the electrical heating may include Joule heating (i.e., heating that follows Ohm's law). Joule heating, also known as resistive heating, resistance heating, or ohmic heating, may include passing an electric current through a material (e.g., an electrical resistor, a catalyst, a catalytic material, or a catalytic bed) to create heat or thermal energy. In some cases, when the catalyst is heated using multiple heating units, the catalyst may be used to produce hydrogen from a feed material including ammonia. In some embodiments, the first portion and the second portion may be the same portion of the catalyst. In another embodiment, the first portion and the second portion may be different portions of the catalyst. In some cases, the first portion and the second portion may overlap or partially overlap.

[0166] In some cases, the first heating unit of the reactor or reformer may be configured to heat the first portion of the catalyst based on combustion of hydrogen gas produced using the second reactor or reformer. In some cases, the first heating unit may be configured to heat the first portion of the catalyst based on combustion of (i) one or more fuel cells in fluid communication with the reactor or (ii) residual hydrogen gas from the second reactor. In some cases, the second heating unit may be configured to heat the second portion of the catalyst by passing an electric current through the second portion of the catalyst. In some cases, the first portion of the catalyst and the second portion of the catalyst may be contiguous (i.e., physically connected). In other cases, the first portion of the catalyst and the second portion of the catalyst may be separated by a third portion of the catalyst. The third portion of the catalyst may be disposed between the first and second portions of the catalyst. In some cases, the first and second portions of the catalyst may be in thermal communication with each other (e.g., either directly or indirectly via the third portion of the catalyst). In other cases, the first and second portions of the catalyst may not be in thermal communication with each other or need not be in thermal communication with each other.

[0167] In some embodiments, the heat load distribution between the first heating unit and the second heating unit may be adjustable to increase the ammonia conversion efficiency and / or improve the thermal efficiency of the reactor or reformer. The heat load distribution may include a heating power ratio corresponding to a ratio between the heating power of the first heating unit and the heating power of the second heating unit. The heating power of the first heating unit and the second heating unit may be adjusted to achieve a desired ammonia conversion efficiency and thermal efficiency. In some embodiments, the system may further include a controller or processor configured to control the operation of the first heating unit and the second heating unit to adjust the heat load distribution in the reactor module. In some embodiments, such adjustment of the heat load distribution may be performed in real time based on one or more sensor measurements (e.g., temperature measurements) or based on the performance of the reactor or reformer (e.g., ammonia conversion efficiency and / or thermal efficiency of the reactor or reformer). In some embodiments, a heater with two or more heating zones may be used to control the power and heat distribution in the heater. In some embodiments, the system may include multiple heating units. The multiple heating units may include at least two or more heating units. In some cases, the heat load distribution among the at least two or more heating units may be adjustable to increase ammonia conversion efficiency and to improve thermal reforming efficiency of the reactor or reformer. In some cases, each of the at least two or more heating units may have one or more heating zones within the reactor or reformer to enable continuous heat distribution within one or more regions within the reactor module. In some cases, the at least two or more heating units may be configured to heat different zones within the reactor or reformer. In some cases, the at least two or more heating units may be configured to heat one or more of the same zones within the reactor or reformer.

[0168] method

[0169] In another aspect, the disclosure provides a method of manufacturing one or more catalysts for processing ammonia to produce hydrogen. The method may include subjecting the catalyst support to one or more physical or chemical processes to optimize one or more pores of the catalyst support. In some cases, the one or more physical or chemical processes to optimize one or more pores of the catalyst support may include thermal treatment (i.e., controlled heating) of the catalyst support. In some cases, optimizing the one or more pores may include adjusting one or more pore sizes, pore densities, and / or pore volumes of the catalyst support. In some cases, the method may further include thermally or chemically treating a surface of the catalyst support material to optimize one or more pores and / or one or more surface morphologies. In some cases, the catalyst support comprises the shape of a bead, pellet, powder, thin film, monolith, foam, reactor wall, heating element, wire, mesh, or porous solid material. In some cases, the catalyst may be powderless, e.g., a majority of the catalyst may be greater than 1 mm in size.

[0170] In some embodiments, the method further includes depositing a composite support material on a catalyst support, where the composite support material comprises a morphology; and (c) depositing one or more active metals on at least one of the composite support material and the catalyst support, where the one or more active metals comprise one or more nanoparticles configured to conform to the morphology of the composite support material, thereby optimizing one or more active sites on the nanoparticles for ammonia processing. In some embodiments, the composite support material may be deposited using chemical vapor deposition. In some embodiments, the one or more active metals may be deposited using chemical vapor deposition. The active metal may comprise one or more nanoparticles comprising one or more active sites to which one or more ammonia molecules can attach. The one or more ammonia molecules may be configured to bind or attach to one or more active sites of the one or more active metal nanoparticles. The location, orientation, and / or density of the one or more active sites can be determined at least in part based on the morphology and / or surface chemistry or properties of the composite support material. In some embodiments, the morphology may include grain structure, grain size, or grain shape. In some cases, the catalyst support may include at least one of, for example, Al2O3, MgO, CeO2, SiO2, SiC, Y2O3, TiO2, or ZrO2. x O y , Mg x O y , Ce x O y , Si x O y , Y x O y , Ti x O y , or Zr x O yIn some cases, the one or more active metals may include at least one of, for example, ruthenium (Ru), nickel (Ni), rhodium (Rh), iridium (Ir), cobalt (Co), molybdenum (Mo), iron (Fe), platinum (Pt), chromium (Cr), palladium (Pd), or copper (Cu). In some cases, the composite support may include a carbon-based material, a boron-based material, or a metal oxide. The carbon-based material may include, for example, activated carbon (AC), one or more carbon nanotubes (CNTs), one or more carbon nanofibers (CNFs), graphene oxide (GO), graphite, or reduced graphene oxide (rGO). The boron-based material may include, for example, hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs). The metal oxide may be, for example, TiO2, MgO, La2O3, CeO2, Y2O3, one or more CeO2 nanotubes, nanorods or nanocubes, mesoporous silica (e.g., KIT-6), ZrO 2、 The metal oxide may include, for example, chromium oxide (Cr2O3), or calcium oxide (CaO). x O y , Mg x O y , La x O y , Ce x O y , Y x O y , Ce x O y , Zr x O y , Cr x O y , or Ca x O y In some cases, the composite support may include YSZ, hydrotalcite (Mg2Al-LDO), MOF (MIL-101, ZIF), alkali amide (NaNH2, Ca(NH2)2, Mg(NH2)2), inorganic electride (C12A7:e-), halloysite nanotubes (HNT), ABO3 perovskite, AB2O4 spinel, MCM-41.

[0171] In some embodiments, the method may further include thermally activating the one or more active metals. Thermally activating the one or more active metals may induce the growth of one or more nanoparticles of the active metals. In some cases, the one or more nanoparticles may be configured to grow while conforming to the morphology of the composite support material. In some cases, the method may further include promoting the catalyst, the active metal nanoparticles, and / or the composite support material of the catalyst with one or more promoters. The one or more promoters may include, for example, sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba).

[0172] Computer Systems

[0173] In one embodiment, the present disclosure provides a computer system that is programmed or configured to implement the methods of the present disclosure. Figure 10 shows a computer system 1001 that is programmed or configured to implement a method for producing one or more catalysts. The computer system 1001 may be configured to control and / or monitor, for example, the flow of one or more precursor materials to a reaction chamber for producing one or more optimized catalysts, the flow of one or more other fluids to the reaction chamber, where the one or more other fluids include a reactive gas, hydrogen, or a noble gas, the rotation of a rotatable chamber of the reaction chamber, the deposition of various materials on one or more catalyst supports disposed within the rotatable chamber, where the various materials include a composite support material and / or one or more active metal nanoparticles as described elsewhere herein, the heating of the reaction chamber or one or more catalyst supports to promote the growth of active metal nanoparticles and / or the change in morphology of the active metal nanoparticles, the heating of one or more optimized catalysts to promote the decomposition of ammonia to hydrogen, and / or the flow of hydrogen from a reactor or reformer to one or more fuel cells to generate electricity. The computer system 1001 can be, for example, a user's electronic device or a computer system located remotely relative to the electronic device. The electronic device can be a mobile electronic device.

[0174] The computer system 1001 may include a central processing unit (CPU, herein "processor" and "computer processor") 1005, which may be a single-core or multi-core processor, or multiple processors for parallel processing. The computer system 1001 may also include memory or storage locations 1010 (e.g., random access memory, read-only memory, flash memory), electronic storage 1015 (e.g., hard disk), communication interface 1020 (e.g., network adapter) for communicating with one or more other systems, and peripherals 1025, such as cache, other memory, data storage, and / or electronic display adapters. The memory 1010, storage 1015, interface 1020, and peripherals 1025 communicate with the CPU 1005 via a communication bus (solid lines), e.g., a motherboard. The storage 1015 may be a data storage device (or data repository) for storing data. The computer system 1001 may be operatively coupled to a computer network ("network") 1030 using the communication interface 1020. The network 1030 can be the Internet, an Internet and / or an extranet, or an intranet and / or an extranet in communication with the Internet. In some cases, the network 1030 is a telecommunications network and / or a data network. The network 1030 can include one or more computer servers, which can enable distributed computing, such as cloud computing. The network 1030 can, in some cases, implement a peer-to-peer network using the computer system 1001, whereby devices coupled to the computer system 1001 can act as clients or servers.

[0175] The CPU 1005 can execute a series of machine-readable instructions, which may be embodied in a program or software. The instructions may be stored in a memory location, such as the memory 1010. The instructions may be directed to the CPU 1005, which may then be programmed or configured to execute the methods of the present disclosure. Examples of operations performed by the CPU 1005 may include fetch, decode, execute, and writeback.

[0176] The CPU 1005 may be part of a circuit, such as an integrated circuit. One or more other components of the system 1001 may be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).

[0177] The storage device 1015 can store files, such as drivers, libraries, and saved programs. The storage device 1015 can store user data, such as user settings and user programs. The computer system 1001 may optionally include one or more other data storage devices located outside the computer system 1001 (e.g., on a remote server in communication with the computer system 1001 via an intranet or the Internet).

[0178] The computer system 1001 can communicate with one or more remote computer systems via the network 1030. For example, the computer system 1001 can communicate with a remote computer system of a user (e.g., an individual operating a reaction chamber to produce one or more optimized catalysts, an entity monitoring the operation of a reactor or reformer comprising one or more optimized catalysts, or an end user operating an apparatus or vehicle that can be powered using electrical energy derived or created from hydrogen produced using a reactor). Examples of remote computer systems include a personal computer (e.g., a portable PC), a slate or tablet PC (e.g., Apple® iPad®, Samsung® Galaxy Tab), a phone, a smartphone (e.g., Apple® iPhone®, Android®-enabled devices, Blackberry®), or a personal digital assistant. A user can access the computer system 1001 via the network 1030.

[0179] The methods described in this disclosure may be performed by machine (e.g., a computer processor) executable code stored in electronic memory locations of the computer system 1001, such as memory 1010 or electronic storage 1015. The machine executable or machine readable code may be provided in the form of software. During use, the code may be executed by the processor 1005. In some cases, the code may be retrieved from storage 1015 and stored in memory 1010 for ready access by the processor 1005. In some cases, the electronic storage 1015 may be excluded and the machine executable instructions are stored in memory 1010.

[0180] The code can be precompiled and configured for use on a machine having a processor adapted to execute the code, or it can be compiled on the fly. The code can be provided in a programming language, which can be selected so that the code can be executed in precompiled or compiled form.

[0181] Aspects of the systems and methods provided herein, such as the computer system 1001, can be embodied in programming. Various aspects of the technology can be thought of as a "product" or "article of manufacture," typically in the form of machine (or processor) executable code and / or associated data carried on or embodied in a type of machine-readable medium. The machine-executable code can be stored on an electronic storage device, such as a memory (e.g., read-only memory, random access memory, flash memory) or a hard disk. A "storage" type medium may include any or all of the tangible memory of a computer, a processor, etc., or their associated modules, such as various semiconductor memories, tape drives, disk drives, etc., which can provide non-transitory storage at any time for software programming. All or parts of the software may sometimes be communicated over the Internet or various other communication networks. Such communication can, for example, allow the software to be loaded from one computer or processor to another, for example, from a management server or host computer to the computer platform of an application server. Thus, other types of media that may carry software elements include the optical, electrical, and electromagnetic waves used across physical interfaces between local devices, over wired and optical landline networks, and over various air links. The physical elements that transmit such waves, e.g., wired or wireless links, optical links, etc., may also be considered media carrying the software. As used herein, unless limited to non-transitory, tangible "storage" media, the term, e.g., computer or machine "readable medium," refers to any medium that participates in providing instructions to a processor for execution.

[0182] Thus, the machine-readable medium, e.g., computer executable code, can take many forms, including but not limited to tangible storage media, carrier wave media, or physical transmission media. For example, non-volatile storage media, including optical or magnetic disks, or any storage device, such as any computer, may be used to implement the databases, etc., shown in the figures. Volatile storage media include dynamic memory, e.g., main memory of such a computer platform. Tangible transmission media include coaxial cables, copper wire, and fiber optics, including wiring, including a bus within a computer system. Carrier wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) communications. Thus, common forms of computer readable media include, for example, a floppy disk, a flexible disk, a hard disk, a magnetic tape, any other magnetic medium, a CD-ROM, a DVD or DVD-ROM, any other optical medium, a paper tape of punch cards, any other physical storage medium having a pattern of holes, a RAM, a ROM, a PROM and an EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transmitting data or instructions, a cable or link transmitting such a carrier wave, or any other medium from which a computer can read programming code and / or data. Many of these forms of computer readable media may be involved in transmitting one or more sequences of one or more instructions to a processor for execution.

[0183] The computer system 1001 may include or communicate with an electronic display 1035 with a user interface (UI) 1040 to provide a portal for a user to monitor or track the operation or performance of one or more reaction chambers used to produce various optimized catalysts, for example. The portal may be provided via an application programming interface (API). A user or entity may also interact with various elements in the portal via the UI. Examples of UIs include, but are not limited to, graphical user interfaces (GUIs) and web-based user interfaces.

[0184] The methods and systems of the present disclosure may be implemented by one or more algorithms. The algorithms may be implemented by software when executed by the central processing unit 1005. For example, the algorithms may be configured to control the operation of one or more reaction chambers that can be used to produce an optimized catalyst based on one or more sensor measurements (e.g., temperature measurements, flow rates, etc.). In some cases, the algorithms may be configured to control the flow of one or more precursor materials to the reaction chamber to produce the one or more optimized catalysts, the flow of one or more other fluids to the reaction chamber, where the one or more other fluids include a reactive gas, hydrogen, or a noble gas, the rotation of a rotatable chamber of the reaction chamber, the deposition of various materials on one or more catalyst supports disposed within the rotatable chamber, where the various materials include a composite support material and / or one or more active metal nanoparticles as described elsewhere herein, the heating of the reaction chamber or one or more catalyst supports to promote the growth of active metal nanoparticles and / or the change in morphology of the active metal nanoparticles, the heating of one or more catalysts optimized to promote the decomposition of ammonia to hydrogen, and / or the flow of hydrogen from the reactor or reformer to one or more fuel cells to generate electricity.

[0185] Selection of catalyst precursor

[0186] In some cases, a catalyst may be used to facilitate the ammonia decomposition reaction. The catalyst may include, for example, a ruthenium nanoparticle catalyst. The ruthenium nanoparticle catalyst may include one or more ruthenium nanoparticles. The ruthenium nanoparticle catalyst may be utilized to facilitate the ammonia decomposition reaction described elsewhere herein and may be prepared by supporting a selected precursor on an alumina support or modified alumina support and reducing at elevated temperatures.

[0187] In some embodiments, a metal salt or metal salt hydrate, such as MNO3, may first be deposited on the surface of an alumina support and then calcined at high temperature to produce an M-Al oxide support. As used herein, M may refer to any type of metal. In some cases, the M-Al oxide may form an alumina-supported perovsite phase, MAlO3 / Al2O3. In some cases, more than one metal salt or metal salt hydrate may be added to produce a mixed M1-M2-Al oxide support. A ruthenium precursor may be deposited on the support, and the support and / or the ruthenium precursor may be reduced at high temperature (e.g., at high temperature in the range of about 500°C to about 1200°C) to produce an optimized nanoparticle catalyst. In some cases, a promoter may be added to the catalyst in the form of an electron donor, such as Cs or K, which may further improve the ammonia conversion efficiency.

[0188] In some cases, the ruthenium nanoparticle catalysts of the present disclosure are, for example, Ru(NO)(NO3)3, RuCl3, and Ru3(CO). 12 Ruthenium may be synthesized using a variety of ruthenium precursors, including Ru(NO)(NO3)3, RuCl3, or Ru3(CO). 12 FIG. 1 shows the effect of ruthenium precursors on the ammonia conversion efficiency of various catalysts synthesized using different precursors including: In some cases, the ruthenium nitrosyl nitrate precursor may result in a more active catalyst, as evidenced by the improved ammonia conversion efficiency of the catalyst made using the ruthenium nitrosyl nitrate precursor.

[0189] Catalyst carrier size

[0190] In some cases, the catalysts of the present disclosure may be synthesized using various alumina supports. The alumina supports may be in the form of beads or cylindrical pellets, or a combination of both. In some cases, the alumina supports may include any type of porous solid material. In other cases, the alumina supports may include beads, pellets, powders, monoliths, foams, or any combination thereof. Figure 12 shows the effect of the physical properties and material composition of the alumina supports or supports on the ammonia conversion efficiency of various catalysts synthesized using alumina supports or supports with different sizes of beads or pellets. In Figure 12, the legend indicates whether the support or support is in the form of beads or pellets (e.g., cylindrical pellets), as well as the diameter of the beads (or height and diameter in the case of cylindrical pellets) in mm. For example, 1.0 beads indicates a support composed of beads with a diameter of 1.0 mm. In this data set, RuCl3 was used as the precursor in all cases, and the precursor was reduced at about 500°C. In some cases, a smaller particle size may result in a more active catalyst. In some non-limiting embodiments, the beads or pellets may have a diameter ranging from about 0.1 millimeters (mm) to about 10 mm. In some non-limiting embodiments, the beads or pellets may have a diameter ranging from about 50 mm to about 100 mm. 2 / g~about 500m 2 The surface area per unit mass may be in the range of 1 / g.

[0191] Reduction Temperature

[0192] As mentioned above, once the ruthenium precursor is deposited on the alumina support or carrier, reduction of the precursor can obtain an optimized ruthenium nanoparticle catalyst that can be used to promote ammonia decomposition. Such reduction conditions can strongly affect the physical or chemical properties or characteristics of the ruthenium on the surface of the carrier, and thereby the activity and / or ammonia conversion efficiency of the catalyst; alternatively, or in addition, the reduction conditions can strongly affect the properties of the ruthenium nanoparticles on the surface, including, for example, size, dispersion, and primary crystal planes. Figure 13 shows the effect of reduction temperature on the ammonia conversion efficiency of Ru / La-gamma-Al2O3 catalysts synthesized by reduction at different temperatures, for example, reduction temperatures ranging from about 500°C to about 900°C. In some cases, as exemplified in Figure 13, a higher reduction temperature can result in a catalyst with significantly higher activity.

[0193] Alumina support phase

[0194] Gamma-alumina is the alumina phase commonly used as a catalyst support, but other phases of alumina exist, including alpha, theta, delta, and eta. Alpha-alumina (α-Al2O3) can be provided in a highly sintered form of support with very low surface area, which can lead to poor catalyst dispersion. In contrast, theta-alumina (θ-Al2O3) can be a phase that is produced during the gamma to alpha transition at very high temperatures and can retain a relatively high surface area, making theta-alumina an example of an optimal support material. Figure 14 shows a comparison of the ammonia conversion efficiency of Ru / La-Al2O3 catalysts synthesized using various catalyst supports including theta-alumina or gamma-alumina (γ-Al2O3). In some cases, the ammonia conversion efficiency of ruthenium on 1.6 mm theta-alumina beads can be higher than the ammonia conversion efficiency of catalysts synthesized on 1.6 mm gamma-alumina beads. In some cases, 1.6 mm theta-alumina beads provide equivalent or higher ammonia conversion efficiency than 1.0 mm gamma-alumina beads. In some cases, pressure drop can be greater in commercial scale reactors and may be a function of the size of the support used, and pressure drop can increase as the particles get smaller. In some cases, switching the support phase from gamma-alumina to theta-alumina can allow the catalyst to perform equivalent to smaller catalysts while still minimizing pressure drop as the catalyst size increases.

[0195] Mixed La-Ce-Al oxide support

[0196] In some cases, the alumina support may be first modified with the incorporation of lanthanum by high temperature calcination to produce a La-Al oxide support capable of functioning as an optimized catalyst support. In some cases, the La-Al oxide support may include an alumina support perovskite structure. In some embodiments, the incorporation of lanthanum may include at least about 5 mol% lanthanum, about 6 mol% lanthanum, about 7 mol% lanthanum, about 8 mol% lanthanum, about 9 mol% lanthanum, about 10 mol% lanthanum, about 11 mol% lanthanum, about 12 mol% lanthanum, about 13 mol% lanthanum, about 14 mol% lanthanum, about 15 mol% lanthanum, about 16 mol% lanthanum, about 17 mol% lanthanum, about 18 mol% lanthanum, about 19 mol% lanthanum, about 20 mol% lanthanum, about 21 mol% lanthanum, about 22 mol% lanthanum, about 23 mol% lanthanum, about 24 mol% lanthanum, or about 25 mol% lanthanum. In some embodiments, the incorporation of lanthanum may include up to about 25 mol% lanthanum, up to about 24 mol% lanthanum, up to about 23 mol% lanthanum, up to about 22 mol% lanthanum, up to about 21 mol% lanthanum, up to about 20 mol% lanthanum, up to about 19 mol% lanthanum, up to about 18 mol% lanthanum, up to about 17 mol% lanthanum, up to about 16 mol% lanthanum, up to about 15 mol% lanthanum, up to about 14 mol% lanthanum, up to about 13 mol% lanthanum, up to about 12 mol% lanthanum, up to about 11 mol% lanthanum, up to about 10 mol% lanthanum, up to about 9 mol% lanthanum, up to about 8 mol% lanthanum, up to about 7 mol% lanthanum, up to about 6 mol% lanthanum, up to about 5 mol% lanthanum, or less.In some embodiments, the lanthanum incorporation may include a mol % of lanthanum in the range of about 5 mol % to about 25 mol %, about 6 mol % to about 24 mol %, about 7 mol % to about 23 mol %, about 8 mol % to about 22 mol %, about 9 mol % to about 21 mol %, about 10 mol % to about 20 mol %, about 11 mol % to about 19 mol %, about 12 mol % to about 18 mol %, about 13 mol % to about 17 mol %, or about 14 mol % to about 16 mol %.

[0197] In some cases, doping of the La-Al oxide support with an electron donor metal, such as cerium, can be used to form the La-Al oxide of the general formula 1-x Ce x A La-Ce-Al oxide support of AlO3 / Al2O3 may be produced, which may result in a more active catalyst. 1-x Ce x The AlO3 / Al2O3 composition may, for example, include a mixed La-Ce oxide structure. FIG. 15 compares the ammonia conversion efficiency of La-Al oxide supports, Ce-Al oxide supports, and mixed La-Ce-Al oxide supports. In some cases, as shown in FIG. 15, catalysts synthesized on mixed La-Ce-Al oxide supports may exhibit superior ammonia conversion efficiency compared to samples on La-Al oxide or Ce-Al oxide supports. In some cases, the catalyst or a portion thereof may include a mixed oxide structure. The mixed oxide structure may include, for example, La, Ce, and / or oxygen.

[0198] FIG. 16 shows a comparison of catalysts prepared using various combinations of optimized parameters shown in the previous figures (FIGS. 11-14). Catalysts prepared using such optimized parameter combinations may exhibit performance characteristics (e.g., ammonia conversion or ammonia conversion efficiency) superior to both "unoptimized" catalysts that are neither chemically nor physically treated, and various other high-performance catalysts previously reported. In some cases, further improvements in ammonia conversion efficiency may be realized by (i) extending the reduction time to about 2 hours to about 12 hours at temperatures ranging from about 700° C. to about 1200° C., and / or (ii) adding a promoter (e.g., Cs) to ruthenium. In some embodiments, the molar ratio of promoter Cs to ruthenium may be at least about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, or about 1:1. In some embodiments, the molar ratio of promoter Cs to ruthenium may be about 1:1 or less, about 2:1 or less, about 3:1 or less, about 4:1 or less, about 5:1 or less, about 6:1 or less, about 7:1 or less, about 8:1 or less, about 9:1 or less, or about 10:1 or less. In some embodiments, the molar ratio of promoter Cs to ruthenium may range from about 1:1 to about 10:1, from about 2:1 to about 9:1, from about 3:1 to about 8:1, from about 4:1 to about 7:1, or from about 5:1 to about 6:1.

[0199] Mixed La-Ce-Al oxide support and promotion of Cs with theta-alumina

[0200] Referring to Figure 17, in some cases, the catalysts of the present disclosure can be further optimized by adjusting the La:Ce ratio. Such further optimization may result in catalysts that exhibit improved performance characteristics compared to other catalysts produced using various baseline conditions. In some non-limiting examples, the baseline conditions may correspond to the amount of Ru incorporation, the molar ratio of Cs promoter to Ru, the type of Ru precursor, the catalyst reduction temperature, the catalyst reduction period, and the alumina support phase. In some embodiments, the incorporation of Ru comprises at least about 0.5 wt%, about 1.0 wt%, about 1.5 wt%, about 2.0 wt%, about 2.5 wt%, about 3.0 wt%, about 3.5 wt%, about 4.0 wt%, about 4.5 wt%, about 5.0 wt%, about 5.5 wt%, about 6.0 wt%, about 6.5 wt%, about 7.0 wt%, about 7.5 wt%, about 8.0 wt%, about 8.5 wt%, about 9.0 wt%, about 9.5 wt%, about 10.0 wt%, about 10.5 wt%, about 11.0 wt%, about 11.5 wt%, about 12 wt%, about 12.5 wt%, about 13 wt%, about 13.5 wt%, about 14 wt%, about 14.5 wt%, or about 15.0 wt%. In some embodiments, the incorporation of Ru is 15.0 wt% or less, about 14.5 wt% or less, about 14.0 wt% or less, about 13.5 wt% or less, about 13.0 wt% or less, about 12.5 wt% or less, about 12.0 wt% or less, about 11.5 wt% or less, about 11.0 wt% or less, about 10.5 wt% or less, about 10.0 wt% or less, about 9.5 wt% or less, about 9.0 wt% or less, about 8.5 wt% or less including about 8.0% or less, about 7.5% or less, about 7.0% or less, about 6.5% or less, about 6.0% or less, about 5.5% or less, about 5.0% or less, about 4.5% or less, about 4.0% or less, about 3.5% or less, about 3.0% or less, about 2.5% or less, about 2.0% or less, about 1.5% or less, about 1.0% or less, or about 0.5% or less by weight.In some embodiments, the incorporation of Ru includes about 0.5 wt% to about 15.0 wt%, about 1.0 wt% to about 14.5 wt%, about 1.5 wt% to about 14.0 wt%, about 2.0 wt% to about 13.5 wt%, about 2.5 wt% to about 13.0 wt%, about 3.0 wt% to about 12.5 wt%, about 3.5 wt% to about 12.0 wt%, about 4.0 wt% to about 11.5 wt%, about 4.5 wt% to about 11.0 wt%, about 5.0 wt% to about 10.5 wt%, about 5.5 wt% to about 10.0 wt%, about 6.0 wt% to about 9.5 wt%, about 6.5 wt% to about 9.0 wt%, about 7.0 wt% to about 8.5 wt%, or about 7.5 wt% to about 8.0 wt% Ru.

[0201] In some embodiments, the molar ratio of promoter (e.g., Cs) to active metal (e.g., Ru) is at least about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, or about 1:1. In some embodiments, the molar ratio of promoter (e.g., Cs) to active metal (e.g., Ru) is about 1:1 or less, about 2:1 or less, about 3:1 or less, about 4:1 or less, about 5:1 or less, about 6:1 or less, about 7:1 or less, about 8:1 or less, about 9:1 or less, or about 10:1 or less. In some embodiments, the molar ratio of promoter (e.g., Cs) to active metal (e.g., Ru) is in the range of about 1:1 to about 10:1, about 2:1 to about 9:1, about 3:1 to about 8:1, about 4:1 to about 7:1, or about 5:1 to about 6:1.

[0202] In some embodiments, the Ru precursor is Ru(NO)(NO3)3, RuCl3, and / or Ru3(CO). 12In some embodiments, the catalytic reduction temperature may be at least about 500° C., about 550° C., about 600° C., about 650° C., at least about 700° C., about 750° C., about 800° C., about 850° C., about 900° C., about 950° C., about 1000° C., about 1050° C., about 1100° C., or more. In some embodiments, the catalytic reduction temperature is about 1100° C. or less, about 1050° C. or less, about 1000° C. or less, about 950° C. or less, about 900° C. or less, about 850° C. or less, about 800° C. or less, about 750° C. or less, about 700° C. or less, about 650° C. or less, about 600° C. or less, about 550° C. or less, about 500° C. or less, or less. In some embodiments, the catalytic reduction temperature may be in the range of about 500°C to about 1100°C, about 550°C to about 1050°C, about 600°C to about 1000°C, about 650°C to about 950°C, about 700°C to about 900°C, about 750°C to about 850°C, or about 800°C to about 850°C. In some embodiments, the catalyst reduction period may be at least 0.5 hours, about 1 hour, about 5 hours, about 10 hours, about 15 hours, about 20 hours, about 25 hours, about 30 hours, about 35 hours, about 40 hours, about 45 hours, about 50 hours, about 55 hours, about 60 hours, about 65 hours, about 70 hours, about 75 hours, about 80 hours, 85 hours, about 90 hours, about 95 hours, about 100 hours, about 110 hours, about 120 hours, about 130 hours, about 140 hours, about 150 hours, about 160 hours, about 170 hours, about 180 hours, about 190 hours, or about 200 hours. In some embodiments, the catalyst reduction period may be about 200 hours or less, about 190 hours or less, about 180 hours or less, about 170 hours or less, about 160 hours or less, about 150 hours or less, about 140 hours or less, about 130 hours or less, about 120 hours or less, about 110 hours or less, about 100 hours or less, about 95 hours or less, about 90 hours or less, about 85 hours or less, about 80 hours or less, about 75 hours or less, about 70 hours or less, about 65 hours or less, about 60 hours or less, about 55 hours or less, about 50 hours or less, about 45 hours or less, about 40 hours or less, about 35 hours or less, about 30 hours or less, about 25 hours or less, about 20 hours or less, about 15 hours or less, about 10 hours or less, about 5 hours or less, about 1 hour or less, or about 0.5 hours or less.In some embodiments, the catalyst reduction period may be in the range of about 0.5 hours to about 200 hours, about 1 hour to about 190 hours, about 5 hours to about 180 hours, or about 10 hours to about 170 hours, about 15 hours to about 160 hours, about 20 hours to about 150 hours, about 25 hours to about 140 hours, or about 30 hours to about 130 hours, about 35 hours to about 120 hours, about 40 hours to about 110 hours, about 45 hours to about 100 hours, or about 50 hours to about 95 hours, about 55 hours to about 90 hours, about 60 hours to about 85 hours, about 65 hours to about 80 hours, or about 70 hours to about 75 hours.

[0203] In any of the embodiments described herein, the alumina support phase may be theta-alumina, gamma-alumina, or a combination of both. In some embodiments, a mixed La-Ce-Al oxide structure may be introduced on or to a support comprising theta-alumina by varying the molar ratio of La to Ce, as shown in FIG. 17. In some embodiments, the molar ratio of La to Ce may be at least about 100:0, about 90:10, about 80:20, about 70:30, about 60:40, about 50:50, about 40:60, about 30:70, about 20:80, about 10:90, or about 0:100. In some cases, there may be an upward trend in activity or ammonia conversion efficiency as a function of cerium content in the support.

[0204] Mixed ZrO2-CeO2 support

[0205] In some embodiments, the present disclosure provides a catalyst for cracking ammonia. In some cases, the conversion efficiency during ammonia decomposition can be correlated with the binding energy (i.e., M-N binding energy) between the catalyst metal (e.g., ruthenium) and nitrogen. Without being bound to a particular theory, the ammonia conversion efficiency of a catalyst for decomposing ammonia may depend on the balance between (i) the energy / kinetics of binding nitrogen to the metal and (ii) the energy / kinetics of releasing nitrogen from the metal. Under some set of measurement conditions, ruthenium (Ru) is an example of a metal catalyst that can provide a high turnover frequency (TOF) for ammonia decomposition compared to some of the other single metal catalysts selected from the periodic table. As illustrated in Nature Chemistry, 2.6 (2010), pp. 484-489, a plot of TOF vs. nitrogen binding energy can show a "volcano" shaped curve, with Ru not matching the volcano peak but being closest to the peak among the single metal catalysts. Under other sets of measurement conditions, other binding energies / kinetic parameters (e.g., those associated with other elementary reaction steps involved in ammonia cracking) may be more strongly correlated with the ammonia conversion efficiency of the catalyst for decomposing ammonia. In some embodiments, contemplated herein are methods for producing a catalyst comprising Ru to improve the ammonia conversion efficiency of the Ru containing catalyst.

[0206] FIG. 20 provides examples of some methods contemplated herein for improving the ammonia conversion efficiency of Ru according to some embodiments. In some cases, the catalyst may comprise a support (e.g., ruthenium may be provided on a support). As used herein, a backslash (" / ") may indicate that the material preceding the backslash is supported by the material following the backslash. For example, Ru / CeO2-ZrO2 may indicate a catalyst including ruthenium supported by a CeO2-ZrO2 support. In some cases, "x" and "y", "a" and "b", or any other letters or symbols may be used to indicate stoichiometric coefficients in a material. For example, Cex O y can refer to a material containing Ce atoms and O atoms in a ratio of "x" to "y". When a letter or symbol is used to indicate a stoichiometric coefficient in one material, the letter or symbol does not necessarily mean the same stoichiometric coefficient in another material. For example, Ru / Zr x O y and Ru / Zr x O y -Ce a O b are mentioned in the same sentence or in the same paragraph, the stoichiometric coefficients "x" and "y" are Ru / Zr x O y and Ru / Zr x O y -Ce a O b However, when a letter or symbol is used to indicate multiple locations of a stoichiometric coefficient within a material, the letter or symbol may refer to the same stoichiometric coefficient within a material. For example, Ru / Zr x O y -Ce x O y When "x" is mentioned, it may mean that two occurrences of "x" share the same value and two occurrences of "y" share the same value.

[0207] In some cases, the support may be configured to provide a strong metal-support interaction. In some cases, the strong metal-support interaction may change or enhance the ammonia conversion efficiency of the metal when the metal is disposed on the support. In some cases, the support may be configured to change the electronic structure of the metal on the support. In some cases, the change in electronic structure of the metal may enhance the ammonia conversion efficiency. In some cases, the support may shift the d-band center of the metal when the metal is disposed on the support. In some cases, nitrogen atoms may bond with the metal of the catalyst during the ammonia cracking reaction.

[0208] In some cases, the support may increase the electron occupancy of the metal-nitrogen antibonding orbital when the metal is provided on the support. In some cases, the support may be configured to increase the electron occupancy in the metal-nitrogen antibonding orbital during the ammonia conversion reaction. In some cases, this increase in MN antibonding orbital occupancy may facilitate nitrogen recombination and desorption.

[0209] In some cases, the support may include oxygen vacancies. In some cases, the support may include oxygen vacancies on the support surface. In some cases, an increase in the density of surface oxygen vacancies may reduce the loss of active sites, for example, during synthesis of a catalyst using the support and / or when the catalyst is used. In some cases, an increase in the density of surface oxygen vacancies may increase the interaction between the metal and the support, which may increase the ammonia decomposition efficiency. In some cases, the oxygen vacancies may interact with a metal provided on the surface of the support. In some cases, the oxygen vacancies may contribute electrons to occupy metal-nitrogen antibonding orbitals. In some cases, the oxygen vacancies may include positively charged vacancies in the support. In some cases, the positively charged vacancies may contribute electron occupancy in the metal-nitrogen antibonding orbitals. In some cases, the positively charged vacancies may increase the electron occupancy of the metal-nitrogen antibonding orbitals when the nitrogen atom is bonded to the metal. In some cases, the increase in the electron occupancy of the metal-nitrogen antibonding orbitals may decrease the dissociation energy between the metal and the nitrogen atom. In some cases, the reduction in dissociation energy between the metal and the nitrogen atom increases the dissociation rate of nitrogen from the metal. In some cases, the reduction in dissociation energy between the metal and the nitrogen atom increases the turnover frequency of the catalyst. In some cases, the reduction in dissociation energy between the metal and the nitrogen atom increases the ammonia conversion efficiency of the catalyst. In some cases, the oxygen vacancies can reduce the activation energy of nitrogen desorption. In some cases, the reduction in activation energy of nitrogen desorption can increase the rate of the ammonia decomposition reaction. In some cases, the reduction in activation energy of nitrogen desorption increases the turnover frequency of the catalyst. In some cases, the reduction in activation energy of nitrogen desorption increases the ammonia conversion efficiency. In some cases, the catalyst includes oxygen vacancies at a concentration of about 0.1 mmol / g to about 10 mmol / g. In some cases, the catalyst includes oxygen vacancies at a concentration of about 2 mmol / g to about 6 mmol / g. In some cases, the catalyst includes oxygen vacancies at a concentration of at least about 0.01, 0.1, 1, 10, or 100 mmol / g.In some cases, the catalyst comprises oxygen vacancies at a concentration of up to about 0.01, 0.1, 1, 10, or 100 mmol / g.

[0210] In some cases, the support may comprise a reducible phase on the surface of the support. In some cases, the support may comprise a reduced phase on the surface of the support. In some cases, the reducible phase may comprise a metal oxide (e.g., a reducible oxide). In some cases, the reducible phase may comprise ceria, iron oxide, titanium oxide, samarium oxide, molybdenum oxide, vanadia, chromia, or any combination thereof. In some cases, the reduced phase may comprise in part cerium, iron, vanadium, chromium, or any combination thereof. As used herein, the reduced phase may comprise in part (e.g., substoichiometric Ce x O y Note that the cations may be reduced to the cations (where y<2) phase.

[0211] A variety of processing conditions (e.g., different temperatures, different calcination conditions, different annealing conditions, and different loadings) can be used to make the support. In some cases, a heat treatment in an oxygen-free atmosphere (e.g., annealing under an inert gas, such as N2 or a noble gas) can be used to reduce the reducible phase. In some cases, hydrogen gas can be used to reduce the reducible phase.

[0212] In some cases, reducing the reducible phase may reduce strong acid sites on the surface of the support through the formation of tetragonal ZrO2 phase. In some cases, reducing strong acid sites on the surface of the support may increase the ammonia conversion efficiency. FIG. 21A shows a comparison of hydrogen production rates of catalysts according to some embodiments. For example, under some measurement conditions, one of the catalyst embodiments disclosed herein (Ru / K-10Ce-ZrO2A900) exceeds the hydrogen production rate of some other catalysts disclosed herein. FIG. 21B shows a table describing the conditions under which the catalyst shown in FIG. 21A was tested according to some embodiments. FIG. 22 shows the ammonia conversion efficiency of various catalysts as a function of temperature according to some embodiments. Of the catalysts shown in FIGS. 21A-B, the Ru / K-10Ce-ZrO2A900 catalyst had the highest hydrogen production rate (mol H2 Mol Ru -1 time -1 ), whereas some other catalysts were powders. In some cases, structured catalysts with foam, bead, and / or pellet shapes may be associated with lower activity or ammonia conversion efficiency than catalysts in powder form, for example, if the larger shapes may cause mass transfer limitations and / or changes in the pore network in the manufacturing process. In some cases, the changes in the pore network may involve pore collapse that "traps" the ruthenium nanoparticles inside the beads and / or pellets, which may result in less active metal available for ammonia conversion (due to reduced surface area of ​​the active metal) and lower ammonia conversion efficiency per mass of ruthenium metal deposited (or per mole of ruthenium metal deposited). Nevertheless, some catalysts of the present disclosure that include larger shapes (e.g., beads, pellets, etc.) may exhibit high ammonia catalytic activity that can match or surpass some catalysts in powder form.

[0213] In some cases, the support comprises Al, Si, Zr, Ce, C, or O. In some cases, the support comprises an oxide, e.g., Al x O y , Si x O y , Zr x O y , and reducible oxides, e.g. Ce x O y , V x O y , or Cr x O y (wherein x and y are numbers greater than zero) (e.g., a reducible oxide that forms oxygen vacancies under annealing or reducing heat treatment). In some cases, the support may include at least one of Al2O3, SiO2, ZrO2, CeO2, V2O5, TiO2, Sm2O3, MoO3, or CrO3, or carbon. In some cases, the support may include at least one of Ti x O y , Sm x O y , or Mo x O y In some cases, the support may include at least one of Zr having an amorphous phase, a monoclinic phase, and / or a tetragonal phase. x O y Optionally, the support comprises zirconia (ZrO2). Optionally, Zr x O y is Ce or Ce x O y In some cases, Zr x O y and Ce x O y When mixed, Zr can form an entrapped network. x O y and Ce x O yWhen mixed, they can form a solid solution. In some cases, the solid solution can include a uniform distribution of the cerium dopant. In some cases, the cerium dopant can be highly dispersed. In some cases, the cerium dopant can form small nanoparticles. In some cases, the support can be a solid solution of Ce. x O y In some cases, the solid solution may contain a large number of oxygen vacancies.

[0214] FIG. 25A shows a graph of various amounts of Ce according to some embodiments. x O y and Zr x O y 1 shows the powder XRD (pXRD) spectra of supports containing different amounts of Ce. x O y A series of supports containing Ce were synthesized and pXRD was carried out to characterize the supports. x O y The pXRD spectrum did not show any prominent peaks that could indicate the presence of any Ce. The pXRD spectrum may indicate that the cerium is substantially uniformly distributed within the support. Alternatively, the pXRD spectrum may not show any Ce. x O y If a phase is present, it may indicate that the phase is below the detection limit of the pXRD instrument (e.g., less than 2 nm in size) or that the density of particles greater than 2 nm may be low. In comparison, other support materials (e.g., CeO2-Al2O3) have a low concentration of Ce. x O y In some cases, a pXRD signal indicative of the CeO2-Al2O3 phase may be observed. In the example of CeO2-Al2O3, the CeO2 peak may be observed even when the support is calcined at low temperatures (e.g., below 600°C). The results shown in Figure 25A show that the CeO2 peak is x O y and Zr x O y However, solid solutions (i.e., Zr xO y Cerium incorporated in the x :Ce y )O z It can be shown that it is possible to form

[0215] In some cases, zirconia or Zr x O y can have high thermal stability. In some cases, thermal stability can impart stability to the catalyst. In some cases, thermal stability can reduce the rate of mechanical defects forming or developing in the catalyst. In some cases, thermal stability can reduce the rate of mechanical defect propagation (e.g., crack propagation) in the catalyst. In some cases, thermal stability can reduce the rate of undesirable phase transformations or other thermally induced structural changes in the catalyst (e.g., catalyst diffusion and / or restructuring of the catalyst surface structure that can affect the ammonia conversion efficiency of the catalyst). In some cases, zirconia or Zr x O y In some cases, zirconia or Zr x O y is approximately 1e -6 , 2e -6 , 3e -6 , 4e -6 , 5e -6 , 6e -6 , 7e -6 , 8e -6 , 9e -6 , 10e- 6 , 11e -6 , 12e -6 , 13e- 6 , 14e- 6 , or 15e -6 / K. In some cases, the carrier may have a thermal expansion coefficient of at most about 1e -6 , 2e -6 , 3e -6 , 4e -6 , 5e -6 , 6e -6 , 7e -6 , 8e -6 , 9e -6 , 10e-6 , 11e -6 , 12e -6 , 13e -6 , 14e -6 , or 15e -6 Optionally, zirconia or Zr x O y In some cases, the support may have a melting point of at least about 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, or 3300° C. In some cases, the support may have a melting point of at most about 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100, 3200, or 3300° C.

[0216] In some cases, zirconia or Zr x O y is about 5.68g / cm 3 In some cases, zirconia or Zr x O y has a density 1.5 to about 3 times higher than some other supports (e.g., Al2O3 is about 3.95 g / cm 3 and SiO2 can have a density of about 2.65 g / cm 3 and the activated carbon can have a density of about 2 g / cm 3In some cases, a high catalyst density may allow for a compact reactor design and improve ammonia conversion efficiency. For a given volume, e.g., reactor, a high catalyst density may provide a larger surface area and / or a higher catalyst weight, thereby increasing the amount of catalyst available for ammonia conversion. In some cases, the reactor may include a catalyst with a density of about 0.7 g / mL to about 1.4 g / mL. In some cases, the reactor may include a catalyst with a density of about 0.85 g / mL to about 1.25 g / mL relative to the packed volume inside the reactor. In some cases, the reactor may include a catalyst with a density of about 0.5 g / mL to about 1.5 g / mL relative to the packed volume inside the reactor. In some cases, the reactor may include a catalyst with a density of less than about 0.7 g / mL relative to the packed volume inside the reactor. In some cases, the reactor may be provided with a catalyst having a density of at least about 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5 g / mL. In some cases, the reactor may be provided with a catalyst having a density of at most about 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, or 1.5 g / mL.

[0217] In some cases, zirconia or Zr x O ymay be chemically resistant. In some cases, the chemical resistance may be corrosion-resistant. In some cases, the chemical resistance may be against acids (e.g., strong acids: nitric acid, hydrochloric acid, or sulfuric acid). In some cases, the chemical resistance may be against organic solvents. In some cases, the chemical resistance may be against alkaline environments. In some cases, the chemical resistance may impart stability to the catalyst. In some cases, the chemical resistance may reduce the rate of contamination of the catalyst when the catalyst is used to crack ammonia. For example, the ammonia fed to the catalyst may contain trace amounts of contaminants. In some cases, the chemical resistance of the catalyst may slow or prevent contamination by the contaminants. In some cases, the chemical resistance may reduce the rate of contamination of the catalyst when the catalyst is exposed to contaminating contaminants. In some cases, the chemical resistance may reduce corrosion of the catalyst during the reaction.

[0218] In some cases, the support is Ce. x O y In some cases, the support may include CeO2. In some cases, the support may include Ce x O y In some cases, the support may be doped with Zr x O y and Ce x O y In some cases, Zr x O y and Ce x O y may be substantially mixed. x O y and Ce x O y is Zr x O y and Ce x O yand may be substantially intermixed to the extent that they form a continuous phase. In some cases, the continuous phase does not include any grain boundaries therein. In some cases, the support may include a homogeneous phase including zirconium and cerium within an oxide network. In some cases, the oxide network may include a tetragonal crystal structure. In some cases, the support may include a homogeneous phase including Zr and C. x O y The region including Ce x O y In some cases, the heterogeneous phase may include regions containing Zr x O y Matrix and Ce incorporated within it x O y phase. In some cases, Ce x O y The phase may have a dimension of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 1000, or 10000 nm. x O y The phase may have a dimension of up to about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 1000, or 10000 nm. In some cases, the heterogeneous phase may be Ce. x O y Matrix and Zr incorporated within it x O y phase. In some cases, Zr x O y The phase may have a dimension of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 1000, or 10000 nm. x O y The phase may have a dimension of up to about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 1000, or 10000 nm. x O y The matrix may include a percolating network. x O y The phase may comprise a non-percolating network.

[0219] In some cases, ceria (Cex O y The carrier containing one or more active metal particles 3P 3 / 2 It can lower the binding energy of the electrons in the orbitals. In some cases, (Ce x O y ) may increase the metal-support interaction. In some cases, Ce x O y can be configured to lower the metal-nitrogen bond energy during the ammonia cracking reaction. x O y can be configured to increase the electron occupancy in the metal-nitrogen antibonding molecular orbital during the ammonia cracking reaction. x O y -Doped Zr x O y (or zirconia) supported Ce x O y may be partially reduced. For example, Ce(IV) may be reduced to CeO by oxygen deficiency. (2-x) In the case of the (Zr:Ce)O2 doped phase, the cerium cations may be reduced by oxygen deficiency to generate oxygen vacancies. Note that Ce metal may not be generated by oxygen reduction and deficiency.

[0220] In some cases, Ce x O y One or more XRD peaks of the Ru / Ce doped zirconia catalyst may include a lower diffraction angle compared to one or more corresponding XRD peaks of the undoped catalyst. In some cases, one or more XRD peaks of the zirconia of the Ru / Ce doped zirconia catalyst may include a lower diffraction angle compared to one or more corresponding XRD peaks of the undoped catalyst. In some cases, a catalyst having a Ce to ZrO2 molar ratio of about 20:80 has a lower diffraction angle of about 10:10. x O yIn some cases, the catalyst comprises Ce in an amount of at least about 1, 5, 10, 20, 30, 40, 50 moles of Ce per 100 moles of ZrO2. In some cases, the catalyst comprises Ce in an amount of at least about 10, 20, 30, 40, 50, 60, 70, 80, or 90 moles of Ce per 100 moles of Ce and ZrO2. In some cases, the catalyst comprises Ce in an amount of up to about 10, 20, 30, 40, 50, 60, 70, 80, or 90 moles of Ce per 100 moles of Ce and ZrO2. In some cases, the catalyst comprises ZrO2 in an amount of at least about 1, 5, 10, 20, 30, 40, 50 moles of ZrO2 per 100 parts of Ce and ZrO2. In some cases, the catalyst comprises ZrO2 in an amount of at least about 10, 20, 30, 40, 50, 60, 70, 80, or 90 mol ZrO2 per 100 parts of Ce and ZrO2. In some cases, the catalyst comprises ZrO2 in an amount of at most about 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, or 90 mol ZrO2 per 100 parts of Ce and ZrO2.

[0221] Optionally, the carrier comprises a layer disposed on the carrier. Optionally, the layer comprises Zr x O y In some cases, the layer comprises zirconia. In some cases, the layer comprises Ce. x O y In some cases, the layer includes ceria. In some cases, the layer includes Zr doped with cerium (Ce) and oxygen (O). x O y In some cases, the layer comprises Zr x O y and Ce x O y In some cases, Zr x O y Ce x O y In some cases, it may be doped with Zr x O y and Ce x O y In some cases, the layer may be partially mixed with Zrx O y and Ce x O y In some cases, the layer may have a thickness of at least about 1, 10, 100, 1000, 10000 nm. In some cases, the layer may have a thickness of at most about 1, 10, 100, 1000, 10000 nm.

[0222] In some cases, the molar ratio of Ce to Zr in the layer ranges from about 1:5 to about 1:25. In some cases, the molar ratio of Ce to Zr in the layer ranges from about 1:8 to about 1:12. In some cases, the molar ratio of Ce to Zr in the layer is at least about 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:60, 1:70, 1:80, 1:90, or 1:100. In some cases, the molar ratio of Ce to Zr in the layer is up to about 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:60, 1:70, 1:80, 1:90, or 1:100.

[0223] In some cases, the layer is (Zr x :Ce y )O z In some cases, the layer comprises a plurality of nanoparticles comprising CeO2. In some cases, the layer comprises a plurality of nanoparticles comprising CeO2. 3+ ions and Ce 4+ ions, Ce 3+ Ion Ce 4+ ions in a range of about 0.3 to about 0.9. In some cases, the ratio is in a range of about 0.7 to about 0.8. In some cases, the ratio is in a range of about 0.5 to about 0.9. 3+ Ion Ce 4+ ions is at least about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. 3+Ion Ce 4+ The ratio to the ion is at most about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.

[0224] FIG. 23 shows ammonia conversion versus temperature for various catalysts according to some embodiments. x O y Doped Zr x O y Experiments were conducted to compare various catalysts, including supports. Ammonia conversion efficiency was measured using the P NH3 = 1 atm, and space velocity = 10000 mL NH3 mL cat -1 time -1 The catalyst was tested by ammoniating at 400°C to 550°C. x O y -Doped Zr x O y Catalysts made of supports have improved ammonia conversion efficiency compared to comparative reference catalysts (e.g., 2Ru / ZrO2). In some cases, the ammonia conversion efficiency can be increased by increasing the amount of Ru added to the catalyst. In some cases, the ammonia conversion efficiency can be increased by adding potassium to the catalyst (e.g., by co-precipitating Ce(NO3)3 with KOH during support synthesis). For example, 2Ru-K / 10Ce-ZrO2-A900 (Ru:K ratio 1:1) and 2Ru / K-A900-10Ce-ZrO2-A900 (Ru:K ratio 1:1) provide ammonia conversion efficiency comparable to 8R / 10Ce-ZrO2-A900, replacing about 6 wt% of Ru while maintaining comparable ammonia conversion efficiency. In some cases, supports containing potassium increase ammonia conversion efficiency. Table 1 shows the procedures for synthesizing some of the catalysts disclosed herein. [Table 1]

[0225] In some cases, the ammonia conversion efficiency or turnover frequency may be measured at a set of predetermined conditions, which may include temperature, ammonia pressure, ammonia flow rate, one or more inert gas levels, or any combination thereof.

[0226] In some cases, the support may include a metal oxide phase. FIG. 23A shows a graph of the structure of the support with various amounts of Ce according to some embodiments. x O y and Zr x O y The pXRD spectrum of the support containing Zr x O y When cerium is doped into Zr x O y The doping of the ZrO2 support with 10 mol% Ce (so that the support contains 10 mol% Ce atoms and 90 mol% ZrO2 compounds) may result in a shift of the pXRD peaks of the lattice framework to lower diffraction angles. x O y A peak shift towards lower diffraction angles was observed, consistent with the doping of cerium atoms into the lattice. Further increasing the Ce doping to 15–20 mol% shifted the peak to the right, whereas the control group (undoped Zr x O y ) and at 20 mol% Ce, x O y The results for 20 mol% Ce indicate that the cerium is exsolution / aggregation from the lattice resulting in the formation of individual Ce atoms on the support. x O y This may indicate that nanoparticles are formed. x O y Although ceria nanoparticles are produced, the nanoparticles may be smaller than the size detection limit of the powder XRD instrument (approximately 2 nm). When the amount of Ce is reduced from 20 wt.% to 10 wt.%, Zr x O y It was observed that the intensity of the XRD signal associated with the tetragonal phase of Zr (star) increased. In the absence of Ce,x O y It was observed that the XRD signal indicative of the tetragonal phase of Zr may not be prominent or may be absent. Without being bound to a particular theory, x O y The tetragonal phase of Zr x :Ce y )O z (i.e., Zr x O y and Ce x O y The tetragonal phase may be caused by a solid solution of Zr x O y This may indicate a strong grafting effect of ceria on the surface. At the highest ceria loading of 20 wt%, the excess of Ce x O y The indicated XRD signals were detected (arrows).

[0227] The ammonia conversion efficiency of the catalysts increased in the order of Ru / ZrO2, Ru / 20Ce-ZrO2, Ru / 15Ce-ZrO2, and Ru / 10Ce-ZrO2, as shown in Figure 23B. In some cases, this trend was not observed when cerium was replaced by Zr x O y This may be correlated with the incorporation of tetragonal (Zr x :Ce y )O z This can be correlated with the total intensity of the pXRD signal, which indicates the network structure of the crystalline structure.

[0228] 24A-24B show powder X-ray diffraction (XRD) spectra according to some embodiments. In some cases, co-deposition of KOH with Ce(NO3)3 followed by calcination (e.g., in air) shifts the intermediate peak to the left, indicating incorporation of Ce into the zirconia matrix. In some cases, co-deposition of KOH with Ce(NO3)3 followed by annealing (N2) shifts the peak further to the left, indicating more efficient incorporation of Ce into the zirconia matrix. In some cases, in both K-doped samples, Ce is more readily absorbed. x O y In some cases, the new peaks can be attributed to exsolution and / or aggregation of cerium from the lattice to produce discrete ceria nanoparticles on the support.

[0229] 24C shows the ammonia conversion efficiency of catalysts according to some embodiments. The ammonia conversion efficiency of the samples increased in the order of Ru / ZrO2, Ru / 10Ce-ZrO2-C900, Ru / K-10Ce-ZrO2-C900, and Ru / K-10Ce-ZrO2-A900. In some cases, the ammonia conversion efficiency may be correlated to the incorporation of cerium into the zirconia framework to form a solid solution, as shown using pXRD.

[0230] FIG. 25A shows powder X-ray diffraction (XRD) spectra of supports according to some embodiments. In some cases, as the Ce content decreases, the Zr x O y Without being bound by theory, the tetragonal phase of (Zr x :Ce y )O z The tetragonal network structure of ruthenium may induce a concentration of oxygen vacancies within the support and / or a high density of surface oxygen vacancies. In some cases, the concentration of oxygen and / or the high density of surface oxygen vacancies may lead to a high strength of metal-support interactions. FIG. 25B shows the 3P lattice structure of ruthenium on a support according to some embodiments, as measured using X-ray photoelectron spectroscopy (XPS). 3 / 2The electron binding energy of the electrons in the orbitals is shown. x :Ce y )O z The network structure can provide strong metal-support interactions. In the catalyst shown in FIG. 25B, the tetragonal (Zr x :Ce y )O z The Ru / 10Ce-ZrO2 with the highest network content measured has the highest binding energy, which may indicate that Ru interacts strongly with the 10Ce-ZrO2 support. Without being bound to a particular theory, it is believed that the tetragonal phase (Zr x :Ce y )O z Solid solutions containing Zr may provide an electron-deficient environment at the surface of the support, allowing Ru (e.g., at 10 mol % loading of Ce) to interact strongly with the support. x O y The tetragonal phase of Zr x O y The monoclinic phase of Zr may have a lower surface density of hydroxyl groups than the monoclinic phase of Zr. In some cases, the hydroxyl groups may be Brønsted acid sites. In some cases, a high density of strong acid sites may reduce the ammonia conversion efficiency of the catalyst (e.g., the rate of the ammonia decomposition reaction may be reduced). In some cases, the monoclinic phase of Zr may have a lower surface density of hydroxyl groups than the monoclinic phase of Zr. In some cases, the hydroxyl groups may be Brønsted acid sites. In some cases, a high density of strong acid sites may reduce the ammonia conversion efficiency of the catalyst (e.g., the rate of the ammonia decomposition reaction may be reduced). x O y From tetragonal Zr x O y Transformation into α-hydroxyethyl ether may enhance the ammonia conversion efficiency by reducing the surface density of hydroxyl groups.

[0231] In some cases, (Zr x :Ce y )O z may be performed to produce nanoparticles of CeO2 on the surface. In some cases, the nanoparticles may include a size that is below the spatial resolution of some instruments (e.g., some pXRD instruments). In some cases, the Ce content may be reduced to produce nanoparticles of CeO2 on the surface. 3+ / Ce 4+FIG. 25C shows the Ce / Cu ratio measured using XPS in accordance with some embodiments. 3+ / Ce 4+ In some cases, Ce 3+ / Ce 4+ A high ratio may indicate a small particle size. In some cases, small cerium nanoparticles may indicate a small particle size. 3+ / Ce 4+ In some cases, high Ce ratios may be 3+ / Ce 4+ The ratio may be related to the high dispersion of cerium with small nanoparticles. In some cases, the Ce of cerium 3+ / Ce 4+ The ratio and / or high dispersity may correlate with the ammonia conversion efficiency and the strength of the metal-support interaction, as determined from the ruthenium binding energy (e.g., as measured by XPS). 3+ / Ce 4+ The ratio, strength of metal-support interaction, and ammonia conversion efficiency may increase in the order of Ru / Ce20-ZrO2, Ru / Ce15-ZrO2, and then Ru / Ce10-ZrO2. x O y High Ce caused by small nanoparticles 3+ / Ce 4+ The high ratio and / or high dispersion of Ce may indicate a large number of surface oxygen vacancies. In some cases, dispersing Ce may reduce the loss of active sites due to wetting of Ru by support / vulcanization and induce strong metal-support interactions.

[0232] 26A-26B show powder X-ray diffraction (pXRD) spectra of supports and catalysts annealed at various temperatures, respectively, according to some embodiments. Experiments were conducted to investigate the effect of annealing temperature on the structure of the support or catalyst. In some cases, increasing the annealing temperature increased the Zr x O yIn some cases, increasing the annealing temperature increased the ammonia conversion efficiency of the catalyst, as shown in FIG. 26C. In other cases, the XRD signal of the tetragonal (Zr x :Ce y )O z The correlation between the phase and ammonia conversion efficiency is (Zr x :Ce y )O z It was shown that the high tetragonal network structure of the mixed oxides leads to the reduction of strong acid sites and promotes the reaction rate of the ammonia decomposition reaction. In some cases, the ammonia conversion efficiency of the samples increased in the order of Ru / 10Ce-ZrO2A600C, Ru / 10Ce-ZrO2A700C, Ru / 10Ce-ZrO2A800C, and Ru / 10Ce-ZrO2A900C. In some cases, the catalytic performance was improved by the tetragonality of the support (Zr x :Ce y )O z The total intensity of the XRD signal of the mesh structure correlated with that of the tetragonal (Zr x :Ce y )O z The correlation between the phase and catalytic performance is x :Ce y )O z This may be due to the fact that the tetragonal network structure of the mixed oxides induces strong metal-support interactions, thereby promoting the reaction rate of the ammonia decomposition reaction.

[0233] Figure 27A shows the ammonia conversion efficiency of various catalysts according to some embodiments. Figure 27B shows the ammonia conversion efficiency of ruthenium on a support measured using XPS according to some embodiments. 3 / 2It indicates the electron binding energy of the electrons in the orbital. In some cases, the basicity of the support can be increased by including an alkali promoter (e.g., potassium). In some cases, the increase in basicity of the support can correlate with an increase in electron density of the Ru sites surrounding the basic sites (measured from a decrease in the binding energy of Ru measured by XPS). In some cases, the increase in electron density of Ru can improve the efficiency of the recombination nitrogen elimination step by back-donation of electrons to the Ru-N antibonding orbital. In some cases, the increase in electron density of Ru can weaken the N-H bond, thereby facilitating the cleavage of the N-H bond. In some cases, the catalyst includes one or more promoters.

[0234] In some cases, the catalyst comprises a density of acid sites ranging from about 10 mol / g to about 1000 mol / g. In some cases, the density of acid sites is from about 50 mol / g to about 300 mol / g. In some cases, the density of acid sites is at least about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 mol / g. In some cases, the density of acid sites is at most about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 mol / g. In some cases, the one or more promoters modify the basicity of the support. In some cases, the promoter or promoters comprise an alkali metal and / or an alkaline rare earth metal.

[0235] In some cases, the one or more active metals may be Ru having a binding energy of 460 eV to 465 eV for the electrons in the 3P3 / 2 orbital, Ni having a binding energy of 870 eV to 880 eV for the electrons in the 2P1 / 2 orbital of Ni, Rh having a binding energy of 305 eV to 315 eV for the electrons in the 3d3 / 2 orbital of Rh, Ir having a binding energy of 55 eV to 65 eV for the electrons in the 4f7 / 2 orbital of Ir, Co having a binding energy of 790 eV to 805 eV for the electrons in the 2P1 / 2 orbital of Co, and Fe having a binding energy of 870 eV to 880 eV for the electrons in the 2P1 / 2 orbital of Fe. The binding energy of the electrons in the 4f7 / 2 orbital of Pt is 720 eV to 735 eV, the binding energy of the electrons in the 4f7 / 2 orbital of Pt is 67 eV to 75 eV, the binding energy of the electrons in the 2P1 / 2 orbital of Cr is 585 eV to 595 eV, the binding energy of the electrons in the 3d3 / 2 orbital of Mo is 230 eV to 240 eV, the binding energy of the electrons in the 3d3 / 2 orbital of Pd is 335 eV to 345 eV, and the binding energy of the electrons in the 2p1 / 2 orbital of Cu is 950 eV to 965 eV.

[0236] In some embodiments, the present disclosure provides a method for producing a catalyst. In some cases, the method includes: (i) preparing a catalyst having Ce; x O y or a precursor thereof, and (ii) Zr s O t or a precursor thereof to produce a support comprising cerium (Ce), zirconium (Zr), and oxygen (O), where "x", "y", "s", and "t" are numbers greater than zero. In some cases, the method includes heating the support to a target temperature. In some cases, the method includes depositing one or more promoter precursors on the support to produce a catalyst. In some cases, the catalyst is configured to decompose ammonia to produce hydrogen. In some cases, the catalyst is configured to decompose ammonia to produce hydrogen and nitrogen.

[0237] In some cases, the process is x O y and Zr s O tOptionally, the heating is performed in the presence of an inert gas phase. Optionally, the treatment is performed with an oxide comprising Zr s O t Ce x O y Doping with precursors, Ce x O y and Zr s O t Optionally, the process includes producing a support comprising Ce. x O y Precursor and Zr s O t The precursor is reacted with Ce x O y and Zr s O t and forming a carrier comprising:

[0238] In some cases, Ce x O y The precursors include Ce(NO3)3, cerium nitrate hexahydrate, cerium nitrate xhydrate, cerium chloride, cerium oxide, cerium oxide nanofibers, cerium fluoride, cerium chloride, cerium chloride heptahydrate, cerium chloride hydrate, cerium acetate hydrate, cerium sulfate, cerium nitrate hydrate, cerium nitrate hexahydrate, cerium bromide, cerium ammonium nitrate, cerium acetylacetonate hydrate, cerium iodide, cerium hydroxide, cerium ammonium sulfate dihydrate, cerium sulfate tetrahydrate, cerium carbonate hydrate, or cerium sulfate hydrate.

[0239] In some cases, Zr s O tThe precursors include zirconium n-butoxide, zirconium acetylacetonate, zirconium propoxide, zirconium oxychloride, zirconium hydroxide, zirconium oxide, zirconium oxide nanofibers, zirconium ethoxide, zirconium acetate, zirconium hydroxide, zirconium trifluoroacetylacetonate, zirconium hydride, zirconium acetylacetonate, zirconium chloride, zirconium sulfate hydrate, zirconium butoxide, zirconium carboxyethyl acrylate, zirconium oxynitrate hydrate, zirconium propoxide, or zirconium fluoride.

[0240] In some cases, the target temperature is in the range of about 600°C to about 1200°C. In some cases, the target temperature is in the range of about 700°C to about 1000°C. In some cases, the target temperature is about 900°C. In some cases, the target temperature is at least about 600, 700, 800, 900, 1000, 1100, or 1200°C. In some cases, the target temperature is at most about 600, 700, 800, 900, 1000, 1100, or 1200°C.

[0241] In some cases, the one or more active metal precursors include a Ru precursor, a Ni precursor, a Rh precursor, an Ir precursor, a Co precursor, a Fe precursor, a Pt precursor, a Cr precursor, a Mo precursor, a Pd precursor, or a Cu precursor. In some cases, the ruthenium precursor includes ruthenium iodide, ruthenium acetylacetonate, ruthenium chloride hydrate, ruthenium oxide hydrate, ruthenium chloride, bis(cyclopentadienyl)ruthenium, ruthenium nitrosyl nitrate, ruthenium iodide hydrate, triruthenium dodecacarbonyl, or any combination thereof.

[0242] In some cases, the catalyst comprises about 0.2% to about 20% by weight ruthenium. In some cases, the catalyst comprises about 0.5% to about 5% by weight ruthenium. In some cases, the catalyst comprises at least about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20% by weight ruthenium. In some cases, the catalyst comprises up to about 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 wt.% ruthenium.

[0243] In some cases, the processing further includes (iii) treating the promoter or promoter precursor to produce or obtain a target molar ratio of dopant to Ce in the carrier. In some cases, the promoter precursor includes an alkali metal precursor and / or an alkali rare earth metal precursor. In some cases, the alkali metal of the alkali metal precursor includes Li, Na, K, Rb, Cs, or Fr. In some cases, the alkali rare earth metal of the alkali rare earth metal includes Mg, Ca, Sr, Ba, or Ra.

[0244] In some cases, the promoter precursor comprises potassium methylate, potassium tetrafluoroborate, potassium bifluoride, potassium thiocyanate, potassium disulfite, potassium bisulfate, potassium sulfide, potassium methoxide, potassium trifluoroacetate, potassium dioxide, potassium persulfate, potassium formate, potassium bicarbonate, potassium sorbate, potassium hydroxide, potassium borohydride, potassium dichloroacetate, potassium iodide, potassium chlorate, potassium fluoride, potassium chloride, potassium nitrate, potassium perchlorate, potassium cyanate, or potassium hexachloroiridate.

[0245] In some cases, the promoter precursor is processed in an aqueous solution. In some cases, the promoter precursor is processed in an organic solution. In some cases, the target molar ratio of promoter to Ce ranges from about 0.1:1 to about 3:1. In some cases, the target molar ratio of promoter to Ce is about 1:1.

[0246] In some cases, the method includes drying the support under vacuum. In some cases, the method includes heating the support to a first target temperature. In some cases, the method includes dissolving one or more promoter precursors, Ce, on the support under a second target temperature and hydrogen. x O y , Zr s O t , and / or reducing the mixed oxide. In some cases, the method includes drying the impregnated support in a vacuum prior to depositing one or more promoter or dopant precursors. In some cases, drying the impregnated support includes vacuum drying. In some cases, the vacuum includes a pressure of less than 1 bar. In some cases, the vacuum may include a pressure of less than about 1, 0.1, 0.01, 0.001, 0.0001, or 0.00001 bar. In some cases, the heating includes using an inert gas. In some cases, the heating includes using air. In some cases, the inert gas may include He, Ne, Ar, Kr, Xe, or N2.

[0247] In some cases, the first target temperature is in the range of about 600°C to about 1200°C. In some cases, the first target temperature is in the range of about 700°C to about 1000°C. In some cases, the first target temperature is about 900°C. In some cases, the first target temperature is at least about 600, 700, 800, 900, 1000, 1100, or 1200°C. In some cases, the first target temperature is at most about 600, 700, 800, 900, 1000, 1100, or 1200°C. In some cases, the second target temperature is in the range of about 250°C to about 600°C. In some cases, the second target temperature is in the range of about 250°C to about 450°C. In some cases, the second target temperature is about 300°C. In some cases, the second target temperature is at least about 600, 700, 800, 900, 1000, 1100, or 1200° C. In some cases, the second target temperature is at most about 600, 700, 800, 900, 1000, 1100, or 1200° C.

[0248] In some cases, when the catalyst includes a K promoter and is treated by heating under an inert gas, one or more XRD peaks of the catalyst include a lower diffraction angle compared to one or more corresponding XRD peaks of a catalyst that does not include a K promoter and / or is not treated by heating under an inert gas. In some cases, when the catalyst includes a K promoter and is treated by heating under air, one or more XRD peaks of the catalyst include a higher diffraction angle compared to one or more corresponding XRD peaks of a catalyst that does not include a K promoter and / or is not treated by heating under an inert gas. In some cases, the catalyst includes zirconia or Zr that is not doped with ceria. x O y In some cases, the catalyst is configured to produce an XRD peak of ceria where the promoter is K. In some cases, the processing includes treating one or more promoter precursors to produce / obtain a targeted molar ratio of promoter to Ce in the support. In some cases, the promoter is reduced under hydrogen at a targeted temperature.

[0249] In some cases, the promoter is configured to modify the basicity of the complex oxide support. In some cases, the promoter is configured to increase the electron density of the active metal to promote the detachment of recombined nitrogen and / or the cleavage of N-H bonds during the ammonia decomposition reaction.

[0250] In some cases, the catalyst may include a nanorod support. In some cases, the support may include Ce x O y In some cases, the nanorod support may advantageously improve ammonia conversion efficiency compared to other shapes. In some cases, the nanorod support may include one or more nanorods comprising Zr s O t Immobilizing or growing CeO2 nanorods on the support may further improve the efficiency of the final catalyst. In some cases, the nanorod support may be produced using hydrothermal synthesis. In some cases, the processing conditions of the hydrothermal synthesis may be adjusted to control the morphology of the support. For example, the morphology of the support may include nanorod diameter, nanorod length, polydispersity, aggregation, or any combination thereof. In some cases, the support may be produced using hydrothermal synthesis to co-precipitate the oxide with the promoter. In some cases, Ce(NO3)3 and KOH may be co-precipitated. As shown in FIG. 27A, co-precipitation of the cerium oxide precursor with the promoter precursor may advantageously result in high ammonia conversion efficiency (e.g., 90% ammonia conversion efficiency at about 450° C.). In some cases, the co-impregnation of the promoter and oxide (e.g., KOH and Ce(NO3)3) may be performed at high pH reaction conditions.

[0251] In some cases, Ce x O y Ru supported on nanorods can advantageously provide high ammonia conversion efficiency. In some cases, zirconia or Zr x O y Celia or Ce on top x O yImmobilization or growth of nanorods of ZnO may further improve the efficiency of the final catalyst.

[0252] 28A-28B show XPS spectra of ruthenium and cerium, respectively, according to some embodiments. In some cases, X-ray photoelectron spectroscopy (XPS) may be used to determine the electron density by measuring the electron binding energy of the electronic states. In some cases, XPS may be used to analyze the electronic states by measuring the electron binding energy in the surface region. Note that a higher binding energy may indicate a greater difficulty in removing the electron. In some cases, a higher binding energy may indicate a more electropositive environment. In some cases, deconvolution of the cerium forms in the XPS spectrum may reveal the presence of Ce. 3+ and Ce 4+ In some cases, the XPS morphology of Ce is complex, so multiple peaks in the XPS spectrum may be possible. In some cases, the catalyst includes one or more nanoparticles or nanorods that include ceria. In some cases, the one or more nanoparticles or nanorods include Zr s O t In some cases, one or more nanoparticles or nanorods are formed by co-impregnation of KOH and Ce(NO3)3.

[0253] In some embodiments, the present disclosure provides a method for producing a catalyst. In some cases, the method includes providing a support comprising alumina. In some cases, the method includes depositing a precursor comprising ruthenium and a precursor comprising phosphorus on the support. In some cases, the method includes treating the support by annealing the support at a first target temperature under N2. In some cases, the method includes treating the support by reducing the support at a second target temperature under H2 to obtain a catalyst.

[0254] In some cases, the catalyst comprises about 0.5 to about 8 wt% Ru. In some cases, the catalyst comprises at least 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt% Ru. In some cases, the catalyst comprises up to 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 wt% Ru. In some cases, the catalyst has a molar ratio of Ru to P of about 0.3 to about 2.5. In some cases, the catalyst has a molar ratio of Ru to P of at least about 0.3, 0.5, 1, 1.5, 2, or 2.5. In some cases, the catalyst comprises a molar ratio of Ru to P of up to about 0.3, 0.5, 1, 1.5, 2, or 2.5.

[0255] In some cases, the method includes drying the support in a vacuum prior to deposition of the Ru precursor. In some cases, the support is dried in a vacuum prior to depositing the layer comprising NaH2PO2. In some cases, the target temperature is in the range of about 500°C to about 1200°C. In some cases, the target temperature is in the range of about 700°C to about 1000°C. In some cases, the target range is at least about 500, 600, 700, 800, 900, 1000, 1100, or 1200°C. In some cases, the target range is up to about 500, 600, 700, 800, 900, 1000, 1100, or 1200°C.

[0256] In some cases, the ruthenium-containing precursor comprises Ru(NO)(NO3)3. In some cases, the phosphorus-containing precursor comprises NaH2PO2. In some cases, the support comprises theta-Al x O y In some cases, the support comprises theta-Al2O3.

[0257] In some embodiments, the present disclosure provides a catalyst. In some cases, the catalyst comprises Al x O yIn some cases, the catalyst includes a support comprising Al2O3. In some cases, the catalyst includes a dopant disposed on the support. In some cases, the catalyst includes one or more active metal particles deposited on the support. In some cases, the support, the dopant, and the one or more active metal particles are configured to decompose ammonia to produce at least hydrogen. ... x O yは θ-Al x O y In some cases, Al2O3 includes θ-Al2O3.

[0258] In some cases, the dopant includes one or more rare earth metals. In some cases, the one or more rare earth metals include an f-block metal. In some cases, the f-block metals include La, Ce, Pr, Nd, and Pm. In some cases, the one or more active metals include Ru, Ni, Rh, Ir, Co, Fe, Pt, Cr, Pd, Mo, or Cu. In some cases, the molar ratio of the one or more rare earth metals of the dopant to Al in the support ranges from about 1:5 to about 1:25. In some cases, the molar ratio of the one or more rare earth metals of the dopant to Al in the support is about 1:15. In some cases, the molar ratio is at least about 1:25, 1:20, 1:15, 1:10, or 1:5. In some cases, the molar ratio is at most about 1:25, 1:20, 1:15, 1:10, or 1:5.

[0259] In some cases, metal phosphide catalysts can be used to decompose ammonia. In some cases, metal phosphides are also used to decompose other reactions, such as electrocatalytic water decomposition (e.g., Ni x P y ) and thermal catalytic alkane dehydrogenation (e.g., Ir x P y ) may be used.

[0260] 29A-29B respectively show the ammonia conversion efficiency of various annealed or reduced RuP catalysts according to some embodiments. Samples were prepared by depositing Ru(NO)(NO3)3 on a theta-aluminum oxide support to give nominal Ru loadings of 1, 3, or 5 wt% on the catalyst. After drying the samples in vacuum, NaH2PO2 was deposited in aqueous solution to achieve final Ru:P molar ratios of approximately 0.5, 1, or 2 to give nominal Ru2P, RuP, and RuP2 phases. Samples were either annealed (under nitrogen) or reduced (under hydrogen) at approximately 900°C.

[0261] As shown in Figure 29A, among the catalysts tested, (3Ru+0.5P) / θ-Al2O3 (which may contain Ru2P phase) had the highest NH3 conversion efficiency at 400°C to 550°C. Among the annealed samples, the nominal RuP and Ru2P phases showed higher ammonia conversion efficiency than the nominal RuP2 phase. Among the reduced samples, the Ru2P phase showed higher ammonia conversion efficiency than the other phases, as shown in Figure 29B.

[0262] In some embodiments, the present disclosure provides a catalyst. In some cases, the catalyst includes a support comprising SiC. In some cases, the catalyst includes a layer disposed on the support, the layer being SiC. x O y In some cases, the catalyst comprises a layer disposed on a support, the layer comprising SiO2. In some cases, the catalyst comprises one or more active metal particles deposited on the layer. In some cases, the support, the layer, and the one or more active metal particles are configured to decompose ammonia to produce at least hydrogen.

[0263] In some cases, the partially oxidized SiC support can have a high thermal conductivity. In some cases, the partially oxidized SiC support can have a high durability. In some cases, the partially oxidized SiC support may have a higher metal loading than a non-oxidized SiC support.

[0264] In some cases, SiC may have high thermal conductivity, stability, and / or chemical resistance. In some cases, SiC may have a relatively small number of metal anchoring sites. In some cases, partially oxidizing the surface of SiC increases the number of metal (e.g., Ru) anchoring sites. In some cases, SiC may be doped with Ce to improve the ammonia conversion efficiency of the catalyst.

[0265] In some cases, the one or more active metals include Ru, Ni, Rh, Ir, Co, Fe, Pt, Cr, Pd, Mo, or Cu. In some cases, the catalyst further includes one or more dopants. In some cases, the one or more dopants include Ce, La, Sm, Pr, Y, Al, Si, Ti, Zr, Ba, Sr, Mg, or Ca. In some cases, at least 90% by weight of the catalyst is greater than 1 mm in at least one dimension.

[0266] In some cases, the support is Si x O y and / or Si x C y In some cases, the support may comprise porous and / or non-porous Si x O y and / or Si x C y FIG. 30 shows a comparison of untreated mesoporous silica pellets (left), mesoporous silica pellets oxidized at 1050° C. (center), and mesoporous silica pellets oxidized at 1200° C. (right) according to some embodiments. In some cases, mesoporous SiC pellets may be oxidized in a muffle furnace at various temperatures to produce a SiO2 phase on the surface of the pellets. In some cases, thermal oxidation of the support may result in a white coloration. In some cases, the white coloration may indicate the formation of SiO2 on the surface of the support.

[0267] FIG. 31 shows the ammonia conversion efficiency of Ru supported on oxidized silicon carbide doped with cerium according to some embodiments.NH3 = 1 atm, and space velocity = 10000 mL NH3 g cat -1 time -1 The ammonia was catalyzed by applying it to the catalyst at

[0268] In some cases, catalyst thermal degradation may be caused by hotspot formation, catalyst agglomeration, and non-uniform ammonia conversion. In some cases, low catalyst thermal conductivity may result in thermal degradation, which may lead to hotspot formation, catalyst agglomeration, and non-uniform ammonia decomposition reactions. In some cases, high catalyst thermal conductivity may reduce the magnitude or risk of one or more thermal degradation mechanisms. In some cases, the high thermal conductivity catalyst may include a structured catalyst and / or bare metal. For example, the structured catalyst may comprise a thin film, a monolith, a foam, a reactor wall, a heating element, one or more wires, meshes, or shapes of porous solid materials. In some cases, the high thermal conductivity catalyst may comprise a high thermal conductivity support. In some cases, other challenges in catalyst design may include overcoming low ammonia conversion efficiency, durability, and catalyst loading.

[0269] In some embodiments, the present disclosure provides a method for decomposing ammonia using any of the aforementioned catalysts disclosed herein to produce at least hydrogen. For example, decomposing ammonia using a catalyst containing Ru as an active metal and K as a promoter (e.g., a molar ratio of Ru to K is 1:1) can convert 98% of ammonia at a temperature of about 500° C. (see, e.g., FIG. 23).

[0270] LIST OF EMBODIMENTS The following list of embodiments of the invention should be considered as disclosing various features of the invention, which features may be considered specific to the particular embodiment in which they are discussed or which may be combined with various other features as listed in other embodiments. Thus, merely because a feature is discussed under one particular embodiment, the use of that feature is not necessarily limited to that embodiment.

[0271] EMBODIMENT 1 1. A method of manufacturing a catalyst for ammonia processing or decomposition, the method comprising: (a) providing a catalyst support; (b) thermally or chemically treating the catalyst support to change the pore characteristics of the catalyst support; (c) depositing a composite support material on the catalyst support, the composite support material having a morphology or surface chemistry or characteristics; and (d) depositing one or more active metals on at least one of the composite support material and the catalyst support, the one or more active metals comprising one or more nanoparticles configured to conform to the morphology or surface chemistry or characteristics of the composite support material when thermally or chemically treated, thereby optimizing one or more active sites on the nanoparticles for ammonia processing or decomposition.

[0272] EMBODIMENT 2 2. The method of embodiment 1, wherein the morphology comprises pore structure, pore size, pore shape, pore volume, pore density, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure.

[0273] EMBODIMENT 3 2. The method of embodiment 1, wherein the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, or hydrophilicity or hydrophobicity.

[0274] EMBODIMENT 4 2. The method of embodiment 1, wherein thermally or electrochemically treating the catalyst support comprises subjecting the catalyst support to one or more physical or chemical processes or treatments to optimize one or more pore or surface chemistries or properties of the catalyst support.

[0275] EMBODIMENT 5 5. The method of embodiment 4, wherein optimizing the one or more pores comprises (i) altering one or more pore sizes, (ii) altering a pore volume of the catalyst support, or (iii) altering a pore density of the catalyst support.

[0276] EMBODIMENT 6 5. The method of embodiment 4, wherein optimizing the surface chemistry or properties comprises altering (i) the Arrhenius acidity or basicity, (ii) the Lewis acidity or basicity, or (iii) the hydrophilicity or hydrophobicity of the surface.

[0277] EMBODIMENT 7 2. The method of embodiment 1, wherein in (c), the composite support material is deposited using physical vapor deposition or chemical vapor deposition.

[0278] EMBODIMENT 8 2. The method of embodiment 1, wherein in (c) the morphology or surface chemistry or properties of the composite support material follows the morphology or surface chemistry or properties of the catalyst support.

[0279] EMBODIMENT 9 2. The method of embodiment 1, wherein in (d), the one or more active metals are deposited using physical vapor deposition or chemical vapor deposition.

[0280] EMBODIMENT 10 2. The method of embodiment 1, wherein (d) further comprises thermally or chemically activating the one or more active metals.

[0281] EMBODIMENT 11 11. The method of embodiment 10, wherein the growth of one or more nanoparticles of the active metal is induced by thermally or chemically activating the one or more active metals.

[0282] EMBODIMENT 12 12. The method of embodiment 11, wherein the one or more nanoparticles are configured to grow, when thermally or chemically activated, conforming to the morphology or surface chemistry or properties of the composite support material.

[0283] EMBODIMENT 13 2. The method of embodiment 1, further comprising promoting the catalyst with one or more promoters to modify or optimize the morphology, active sites, electron density, or electronic state of the catalyst.

[0284] EMBODIMENT 14 11. The method of embodiment 10, wherein the one or more promoters comprise sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba).

[0285] EMBODIMENT 15 2. The method of embodiment 1, wherein the one or more active metals comprise ruthenium (Ru), nickel (Ni), rhodium (Rh), iridium (Ir), cobalt (Co), iron (Fe), platinum (Pt), chromium (Cr), palladium (Pd), or copper (Cu).

[0286] EMBODIMENT 16 2. The method of embodiment 1, wherein the catalyst support comprises aluminum oxide (Al2O3), magnesium oxide (MgO), cerium dioxide (CeO2), silicon dioxide (SiO2), yttrium oxide (Y2O3), one or more zeolites, or titanium dioxide (TiO2).

[0287] EMBODIMENT 17 2. The method of embodiment 1, wherein the composite support material comprises a carbon-based material, a boron-based material, or a metal oxide.

[0288] EMBODIMENT 18 18. The method of embodiment 17, wherein the carbon-based material comprises graphite, activated carbon (AC), one or more carbon nanotubes (CNTs), one or more carbon nanofibers (CNFs), graphene oxide (GO), one or more carbon nanoribbons, or reduced graphene oxide (rGO).

[0289] EMBODIMENT 19 18. The method of embodiment 17, wherein the boron-based material comprises hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs).

[0290] EMBODIMENT 20 18. The method of embodiment 17, wherein the metal oxide comprises titanium dioxide (TiO2), magnesium oxide (MgO), lanthanum oxide (La2O3), cerium dioxide (CeO2), yttrium oxide (Y2O3), one or more CeO2 nanotubes, mesoporous silica, or zirconium dioxide (ZrO2).

[0291] EMBODIMENT 21 13. The method of embodiment 1, further comprising thermally or chemically treating the surface of the catalyst support material to optimize the pore structure or surface chemistry or properties of the catalyst support material.

[0292] EMBODIMENT 22 2. The method of embodiment 1, wherein the one or more ammonia molecules are configured to bind or attach to one or more active sites on the active metal to decompose the one or more ammonia molecules.

[0293] EMBODIMENT 23 23. The method of embodiment 22, wherein the location, orientation, and / or density of the one or more active sites is determined based at least in part on morphology and / or surface chemistry or properties.

[0294] EMBODIMENT 24 2. The method of embodiment 1, wherein the catalyst support comprises the shape of a bead, pellet, powder, thin film, monolith, foam, or porous solid material.

[0295] EMBODIMENT 25 2. The method of embodiment 1, wherein the pore characteristics include pore structure, pore size, pore shape, pore volume, or pore density.

[0296] EMBODIMENT 26 2. The method of embodiment 1, wherein (b) comprises modifying the pore density of the catalyst support.

[0297] EMBODIMENT 27 27. The method of embodiment 26, wherein (b) comprises increasing the pore density of the catalyst support.

[0298] EMBODIMENT 28 1. A catalyst for ammonia processing, the catalyst comprising: a catalyst support having one or more modified pore characteristics produced by thermal or chemical treatment of the catalyst support; a composite support material disposed on the catalyst support, the composite support material having a morphology or surface chemistry or properties; and one or more active metals disposed on or incorporated into at least one of the composite support material and the catalyst support, the one or more active metals including one or more nanoparticles configured to conform to the morphology or surface chemistry or properties of the composite support material when thermally or chemically activated, thereby optimizing one or more active sites on the nanoparticles for the processing or decomposition of ammonia.

[0299] EMBODIMENT 29 29. The catalyst of embodiment 28, wherein the morphology comprises pore structure, pore size, pore shape, pore volume, pore density, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure.

[0300] EMBODIMENT 30 29. The catalyst of embodiment 28, wherein the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, or hydrophilicity or hydrophobicity.

[0301] EMBODIMENT 31 30. The catalyst of embodiment 28, wherein the catalyst support comprises one or more properties or characteristics that can be optimized using one or more physical or chemical processes.

[0302] EMBODIMENT 32 32. The catalyst of embodiment 31, wherein the one or more properties or characteristics include the morphology or surface chemistry or characteristics of the catalyst support.

[0303] EMBODIMENT 33 33. The catalyst of embodiment 32, wherein the morphology comprises pore structure, pore size, pore shape, pore volume, pore density, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure.

[0304] EMBODIMENT 34 33. The catalyst of embodiment 32, wherein the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, or hydrophilicity or hydrophobicity.

[0305] EMBODIMENT 35 29. The catalyst of embodiment 28, wherein the composite support material is deposited using physical vapor deposition or chemical vapor deposition.

[0306] EMBODIMENT 36 29. The method of embodiment 28, wherein the morphology or surface chemistry or properties of the composite support material follows the morphology or surface chemistry or properties of the catalyst support.

[0307] EMBODIMENT 37 29. The catalyst of embodiment 28, wherein the active metal or metals are deposited using physical vapor deposition or chemical vapor deposition.

[0308] EMBODIMENT 38 29. The catalyst of embodiment 28, wherein the active metal or metals are configured to conform to the morphology or surface chemistry or properties of the composite support material when thermally or chemically activated.

[0309] EMBODIMENT 39 39. The catalyst of embodiment 38, wherein the one or more active metals are configured to grow when thermally or chemically activated.

[0310] EMBODIMENT 40 40. The catalyst of embodiment 39, wherein the one or more nanoparticles are configured to grow according to the morphology or surface chemistry or properties of the composite support material.

[0311] EMBODIMENT 41 The catalyst of embodiment 28, wherein the catalyst is promoted with one or more promoters.

[0312] EMBODIMENT 42 42. The catalyst of embodiment 41, wherein the one or more promoters comprise Na, K, Rb, Cs, Mg, Ca, Sr, or Ba.

[0313] EMBODIMENT 43 29. The catalyst of embodiment 28, wherein the one or more active metals comprise Ru, Ni, Rh, Ir, Co, Fe, Pt, Cr, Pd, or Cu.

[0314] EMBODIMENT 44 29. The catalyst of embodiment 28, wherein the catalyst support comprises Al2O3, MgO, CeO2, SiO2, Y2O3, one or more zeolites, or TiO2.

[0315] EMBODIMENT 45 29. The catalyst of embodiment 28, wherein the composite support comprises a carbon-based material, a boron-based material, or a metal oxide.

[0316] EMBODIMENT 46 46. ​​The catalyst of embodiment 45, wherein the carbon-based material comprises graphite, activated carbon (AC), one or more carbon nanotubes (CNTs), one or more carbon nanofibers (CNFs), graphene oxide (GO), one or more carbon nanoribbons, or reduced graphene oxide (rGO).

[0317] EMBODIMENT 47 46. ​​The catalyst of embodiment 45, wherein the boron-based material comprises hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs).

[0318] EMBODIMENT 48 46. ​​The catalyst of embodiment 45, wherein the metal oxide comprises TiO2, MgO, La2O3, CeO2, Y2O3, one or more CeO2 nanotubes, mesoporous silica, or ZrO2.

[0319] EMBODIMENT 49 29. The catalyst of embodiment 28, wherein the morphology or surface chemistry or properties are generated or optimized by thermally or chemically treating the surface of the catalyst support material.

[0320] EMBODIMENT 50 29. The catalyst of embodiment 28, wherein the one or more nanoparticles comprise one or more active sites configured to attach or bind one or more ammonia molecules for decomposition of the one or more ammonia molecules.

[0321] EMBODIMENT 51 The catalyst of embodiment 50, wherein the location, orientation, or density of the one or more active sites is determined at least in part based on morphology or surface chemistry or properties.

[0322] EMBODIMENT 52 29. The catalyst of embodiment 28, wherein the catalyst support comprises the shape of a bead, a pellet, a powder, a thin film, a monolith, a foam, or a porous solid material.

[0323] EMBODIMENT 53 1. A system for manufacturing a catalyst for ammonia processing, the system comprising: a rotatable reaction chamber with one or more heating units, the reaction chamber configured to process one or more catalyst supports to produce one or more catalysts optimized for ammonia processing; and one or more precursor storage chambers in fluid communication with the rotatable reaction chamber, the one or more precursor storage chambers configured to supply a plurality of precursor materials, the plurality of precursor materials including: (i) a first precursor material including one or more functional materials that provide a basis for nanoparticle growth, (ii) a second precursor material including one or more active metal nanoparticles, and (iii) a third precursor material for promoting the one or more active metal nanoparticles.

[0324] EMBODIMENT 54 54. The system of embodiment 53, wherein the one or more heating units are configured to heat the one or more catalyst supports to optimize one or more characteristics or properties of the one or more catalyst supports.

[0325] EMBODIMENT 55 55. The system of embodiment 54, wherein the one or more characteristics or properties include morphology or surface chemistry or properties.

[0326] EMBODIMENT 56 55. The system of embodiment 54, wherein the one or more characteristics or properties include pore size, pore density, or pore volume.

[0327] EMBODIMENT 57 56. The system of embodiment 55, wherein the morphology comprises pore structure, pore shape, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure.

[0328] EMBODIMENT 58 56. The system of embodiment 55, wherein the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, or hydrophilicity or hydrophobicity.

[0329] EMBODIMENT 59 54. The system of embodiment 53, wherein the rotatable reaction chamber comprises one or more inlets for receiving a first precursor material to deposit a layer of the first precursor material on a surface of the one or more catalyst supports.

[0330] EMBODIMENT 60 60. The system of embodiment 59, wherein the layer of the first precursor material is deposited using physical vapor deposition or chemical vapor deposition.

[0331] EMBODIMENT 61 60. The system of embodiment 59, wherein the morphology or surface chemistry or properties of the first precursor material follow the morphology or surface chemistry or properties of the one or more catalyst supports.

[0332] EMBODIMENT 62 62. The system of embodiment 61, wherein the morphology comprises pore structure, pore size, pore shape, pore volume, pore density, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure.

[0333] EMBODIMENT 63 62. The system of embodiment 61, wherein the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, or hydrophilicity or hydrophobicity.

[0334] EMBODIMENT 64 60. The system of embodiment 59, wherein the layer of first precursor material provides a base for growth of one or more active metal nanoparticles.

[0335] EMBODIMENT 65 60. The system of embodiment 59, wherein the rotatable reaction chamber is configured to receive a second precursor material to deposit a layer of the second precursor material on at least one of (i) the surface of the one or more catalyst supports and (ii) the layers of the first precursor material.

[0336] EMBODIMENT 66 66. The system of embodiment 65, wherein the one or more active metal nanoparticles of the second precursor material are configured to grow on the layer of the first precursor material.

[0337] EMBODIMENT 67 67. The system of embodiment 66, wherein the one or more active metal nanoparticles are configured to grow according to the morphology or surface chemistry or properties of a first precursor material when thermally or chemically activated.

[0338] EMBODIMENT 68 66. The system of embodiment 65, wherein the layer of the second precursor material is deposited using physical vapor deposition, chemical vapor deposition, vacuum deposition, or incipient wetness impregnation.

[0339] EMBODIMENT 69 68. The system of embodiment 67, wherein the morphology comprises pore structure, pore size, pore shape, pore volume, pore density, grain structure, grain size, grain shape, crystal structure, flake size, or layered structure.

[0340] EMBODIMENT 70 68. The system of embodiment 67, wherein the surface chemistry or properties include Arrhenius acidity or basicity, Lewis acidity or basicity, or hydrophilicity or hydrophobicity.

[0341] EMBODIMENT 71 66. The system of embodiment 65, wherein the rotatable reaction chamber is configured to receive a third precursor material to dope or promote the layer of the first precursor material, the layer of the second precursor material, or one or more active metal nanoparticles of the second precursor material.

[0342] EMBODIMENT 72 72. The system of embodiment 71, wherein doping comprises impregnating the layer of the first precursor material, the layer of the second precursor material, or the one or more active metal nanoparticles with one or more dopants to modify the morphology, modify the active sites, modify the electron density, or modify the electronic state.

[0343] EMBODIMENT 73 73. The system of embodiment 72, wherein the one or more promoters comprise Na, K, Rb, Cs, Mg, Ca, Sr, or Ba.

[0344] EMBODIMENT 74 66. The system of embodiment 65, wherein one or more heating units are configured to heat the catalyst support comprising (i) a layer of a first precursor material and (ii) a layer of a second precursor material to thermally or chemically activate the one or more active metal nanoparticles to promote growth of the nanoparticles and change in one or more properties or characteristics.

[0345] EMBODIMENT 75 75. The system of embodiment 74, wherein the rotatable reaction chamber is configured to provide a reducing environment for thermal or chemical activation of one or more active metal nanoparticles.

[0346] EMBODIMENT 76 76. The system of embodiment 75, wherein the reducing environment comprises hydrogen or ammonia gas, or one or more noble gases.

[0347] EMBODIMENT 77 54. The system of embodiment 53, wherein the one or more active metal nanoparticles comprise Ru, Ni, Rh, Ir, Co, Fe, Pt, Cr, Pd, or Cu.

[0348] EMBODIMENT 78 54. The system of embodiment 53, wherein the catalyst support comprises Al2O3, MgO, CeO2, SiO2, Y2O3, one or more zeolites, or TiO2.

[0349] EMBODIMENT 79 54. The system of embodiment 53, wherein the one or more functional materials comprise a carbon-based material, a boron-based material, or a metal oxide.

[0350] EMBODIMENT 80 80. The catalyst of embodiment 79, wherein the carbon-based material comprises graphite, activated carbon (AC), one or more carbon nanotubes (CNTs), one or more carbon nanofibers (CNFs), graphene oxide (GO), one or more carbon nanoribbons, or reduced graphene oxide (rGO).

[0351] Embodiment 81 80. The catalyst of embodiment 79, wherein the boron-based material comprises hexagonal boron nitride (hBN), boron nitride nanotubes (BNNTs), or boron nitride nanosheets (BNNSs).

[0352] EMBODIMENT 82 80. The catalyst of embodiment 79, wherein the metal oxide comprises TiO2, MgO, La2O3, CeO2, Y2O3, one or more CeO2 nanotubes, mesoporous silica, or ZrO2.

[0353] EMBODIMENT 83 54. The system of embodiment 53, wherein the rotatable reaction chamber is in fluid communication with one or more gas sources comprising a reactive gas, hydrogen gas, or one or more noble gases.

[0354] EMBODIMENT 84 84. The system of embodiment 83, wherein the reactive gas can be used to chemically modify or optimize one or more pores of the catalyst support.

[0355] EMBODIMENT 85 84. The system of embodiment 83, wherein hydrogen gas and the one or more noble gases can be used to provide a reducing environment during thermal or chemical activation of the one or more active metal nanoparticles.

[0356] EMBODIMENT 86 54. The system of embodiment 53, further comprising one or more mass flow controllers for controlling the flow of fluids or materials into or out of the rotatable reaction chamber.

[0357] EMBODIMENT 87 54. The system of embodiment 53, further comprising a vacuum pump in fluid communication with the rotatable reaction chamber to provide a vacuum environment within the rotatable reaction chamber.

[0358] EMBODIMENT 88 54. The system of embodiment 53, further comprising an additional heating unit for heating or pre-heating multiple precursor materials.

[0359] EMBODIMENT 89 1. A method of manufacturing a catalyst for ammonia processing, comprising: (a) providing an alumina support; (b) depositing one or more metal salts or metal salt hydrates on a surface of the alumina support; (c) calcining the alumina support and / or the one or more metal salts or metal salt hydrates deposited thereon to produce a catalyst support comprising an alumina supported mixed oxide structure; (d) depositing a ruthenium precursor on the catalyst support; and (e) reducing the ruthenium precursor to produce an optimized catalyst comprising one or more ruthenium nanoparticles configured to promote ammonia decomposition.

[0360] EMBODIMENT 90 90. The method of embodiment 89, further comprising adding one or more promoters after or before (e) to further enhance catalytic activity.

[0361] EMBODIMENT 91 91. The method of embodiment 90, wherein the one or more promoters comprise Na, K, Rb, Cs, Mg, Ca, Sr, or Ba.

[0362] EMBODIMENT 92 91. The method of embodiment 90, wherein the molar ratio of the one or more promoters to ruthenium is from about 1:1 to about 10:1, and the ruthenium is obtained from the reduction of a ruthenium precursor in (e).

[0363] EMBODIMENT 93 Ruthenium precursors are Ru(NO)(NO3)3, RuCl3, and Ru3(CO). 12 or any combination thereof.

[0364] EMBODIMENT 94 90. The method of embodiment 89, wherein the alumina support comprises a porous solid material.

[0365] EMBODIMENT 95 90. The method of embodiment 89, wherein the alumina support comprises beads, pellets, powder, monolith, foam, or any combination thereof.

[0366] EMBODIMENT 96 The beads or pellets have (i) a diameter in the range of about 0.1 millimeters (mm) to about 10 mm, and / or (ii) a diameter in the range of about 50 mm. 2 / g~about 500m 2 96. The method of embodiment 95, having a surface area per unit mass in the range of 1 / g.

[0367] EMBODIMENT 97 90. The method of embodiment 89, wherein in (e), the ruthenium precursor is reduced at a temperature in the range of about 500 °C to about 1200 °C.

[0368] EMBODIMENT 98 90. The method of embodiment 89, wherein the alumina support comprises a gamma-alumina phase, or an alpha-alumina phase, or a theta-alumina phase, or a delta-alumina phase, or an eta-alumina phase, or any combination thereof.

[0369] EMBODIMENT 99 90. The method of embodiment 89, wherein the one or more metal salts or metal salt hydrates comprises lanthanum.

[0370] EMBODIMENT 100 90. The method of embodiment 89, wherein in (c), the calcined alumina support comprises lanthanum in a concentration ranging from about 5 mol % lanthanum to about 25 mol % lanthanum.

[0371] EMBODIMENT 101 90. The method of embodiment 89, further comprising doping the alumina support with one or more dopants to obtain a more active catalyst with enhanced catalytic activity.

[0372] EMBODIMENT 102 102. The method of embodiment 101, wherein the one or more dopants comprises cerium.

[0373] EMBODIMENT 103 90. The method of embodiment 89, wherein the catalyst, or a portion thereof, comprises a mixed oxide structure.

[0374] EMBODIMENT 104 104. The method of embodiment 103, wherein the mixed oxide structure comprises a mixture of La, Ce, and oxygen.

[0375] EMBODIMENT 105 105. The method of embodiment 104, wherein the mixture of La and Ce comprises a molar ratio of La to Ce ranging from about 90:10 to about 50:50.

[0376] EMBODIMENT 106 90. The method of embodiment 89, wherein in (e), the reduction is carried out for a period ranging from about 2 hours to about 168 hours.

[0377] EMBODIMENT 107 90. The method of embodiment 89, wherein in (e), the reduction is carried out at a temperature in the range of about 500 °C to about 1200 °C.

[0378] EMBODIMENT 108 90. The method of embodiment 89, wherein the loading of Ru in the catalyst ranges from about 0.5% to about 10% by weight.

[0379] Although the present specification shows and describes preferred embodiments of the present invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. The present invention is not intended to be limited by the specific examples provided herein. Although the present invention has been described with reference to the foregoing specification, the description and illustration of the embodiments herein are not intended to be construed in a limiting sense. Numerous variations, changes, and substitutions will occur to those skilled in the art without departing from the present invention. Furthermore, it should be understood that all aspects of the present invention are not limited to the specific descriptions, configurations, or relative proportions set forth herein, which depend upon a variety of conditions and variables. It is understood that various alternatives to the embodiments of the present invention described herein can be used in carrying out the present invention. It is therefore intended that the present invention cover any such alternatives, modifications, variations, or equivalents. The following claims define the scope of the present invention, and it is intended that methods and structures within the scope of these claims and their equivalents are covered thereby.

Claims

1. A method for reforming ammonia, the method comprising: contacting a gas containing ammonia (NH₃) with a catalyst in a reactor at a temperature in the range of about 400 °C to about 700 °C to produce a reformed stream containing hydrogen (H₂) and nitrogen (N₂) with an ammonia conversion efficiency of at least about 70%, the catalyst comprising: a support comprising a monoclinic structure of zirconium and oxygen; a layer adjacent to the support, the layer comprising a network structure of cerium (Ce), zirconium (Zr) and oxygen having a cubic, monoclinic, or amorphous phase; a promoter selected from the group consisting of alkali metals and alkaline earth metals; active metal particles adjacent to the layer, the active metal particles comprising ruthenium (Ru); comprising; the molar ratio of Ce:Zr in the layer ranges from about 1:5 to about 1:25; the molar ratio of the promoter to the Ce ranges from about 0.1:1 to about 3:1; the concentration of Ru is at least about 0.5 wt% and at most about 5 wt% based on the total weight of the catalyst; and the catalyst produces the reformed stream at a temperature of at least about 500 °C with an ammonia conversion efficiency of more than about 90%.

2. The method according to claim 1, wherein the layer comprises a network structure of cerium, zirconium, and oxygen having a cubic phase.

3. The method according to claim 1, wherein the layer comprises a network structure of cerium, zirconium, and oxygen having cubic and monoclinic phases.

4. The method according to claim 1, wherein the molar ratio of Ce:Zr in the layer ranges from about 1:8 to about 1:

12.

5. The method according to claim 1, wherein the molar ratio of the promoter to the Ce is about 1:

1.

6. The method according to claim 1, wherein the promoter is potassium (K).

7. The method according to claim 1, wherein the concentration of Ru is at least about 0.7% by weight and at most about 2% by weight based on the total weight of the catalyst.

8. When contacting with ammonia at a temperature of 450 °C, a pressure of 1 atmosphere (atm) (PNH3), a space velocity of ammonia of 21,283 milliliters per gram of catalyst per minute (mL NH3 gcat-1 min-1), and a metal addition amount of 1.43%, the catalyst produces hydrogen (H2) at a rate of at least 13.8 millimoles of hydrogen per gram of catalyst per minute (mmol H2 gcat-1 min-1). The method according to any one of claims 1 to 7.

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