Hydrogen production by pyrolysis of hydrocarbons using sub-micron sized high entropy alloy catalysts

Abstract

High-entropy alloy catalysts can be used to produce hydrogen. An exemplary method for producing hydrogen may include: introducing hydrocarbons into a reactor, wherein the reactor contains a catalyst, wherein the reactor is substantially free of oxygen and water, wherein the catalyst comprises a high-entropy alloy and a catalyst support, wherein the catalyst is present in the form of a first plurality of particles, wherein the first plurality of particles are submicron in size, and wherein the high-entropy alloy has an entropy S such that S ≥ 12.47 J·K. ‑1 ·mol ‑1 The high-entropy alloy comprises at least five of the following: iron, cobalt, manganese, nickel, molybdenum, copper, zinc, titanium, chromium, vanadium, aluminum, gallium, ruthenium, rhodium, palladium, silver, indium, tungsten, rhenium, iridium, platinum, gold, and bismuth; and the hydrocarbon is reacted on the catalyst to produce solid carbon and hydrogen.

Description

Technical Field

[0001] This disclosure generally relates to the production of hydrogen. Background Technology

[0002] Hydrogen is an emerging clean fuel source with the potential to power energy storage, power generation, vehicle propulsion, and other applications. Hydrogen can be converted into usable energy (including electricity) with low or no emissions using technologies such as fuel cells, since the byproduct of hydrogen used in fuel cells is water.

[0003] Methane (CH4) derived from natural gas is currently the conventional source for hydrogen production. Conventional methods for producing hydrogen include steam methane reforming (SMR), autothermal methane reforming (ATR), and partial methane oxidation (POM). The main drawback of SMR, ATR, and POM is their high CO2 emissions, which offsets the clean combustion advantages of using hydrogen as a fuel source. Other disadvantages of conventional hydrogen production methods include high energy consumption, high cost, low reaction efficiency, low process efficiency, and low catalyst stability.

[0004] Conventional hydrogen production (including ATR, SMR, and POM) may involve the use of conventional catalyst technologies. Catalyst efficiency is one of the key issues in efficient hydrogen production. Due to factors such as catalyst composition, size effect, surface area effect, porosity, defect density, promoter effect, support effect, coordination state of metals in the catalyst, acid-base properties of the catalyst, or any combination thereof, conventional catalysts may have limited efficiency and limited lifetime. Summary of the Invention

[0005] The following summary outlines various details of this disclosure to provide a basic understanding. This summary is not an exhaustive overview of the invention and is neither intended to identify certain elements of the invention nor to limit its scope. Rather, the main purpose of this summary is to present some concepts of the disclosure in a simplified form before the more detailed description presented below.

[0006] A first non-limiting example method of this disclosure may include: introducing hydrocarbons into a reactor, wherein the reactor contains a catalyst, wherein the reactor is substantially free of oxygen and water, wherein the catalyst comprises a high-entropy alloy and a catalyst support, wherein the catalyst is present in the form of a first plurality of particles, wherein the first plurality of particles are submicron in size, and wherein the high-entropy alloy has an entropy S such that S ≥ 12.47 J·K -1 ·mol -1 The high-entropy alloy comprises at least five of the following: iron, cobalt, manganese, nickel, molybdenum, copper, zinc, titanium, chromium, vanadium, aluminum, gallium, ruthenium, rhodium, palladium, silver, indium, tungsten, rhenium, iridium, platinum, gold, and bismuth; and the hydrocarbon is reacted on the catalyst to produce solid carbon and hydrogen.

[0007] A second non-limiting example method of this disclosure may include: purging a reactor with an inert gas to remove oxygen, water, or a combination thereof, wherein the inert gas includes nitrogen, argon, or any combination thereof; introducing a hydrocarbon into the reactor, wherein the reactor contains a catalyst, wherein the catalyst comprises a high-entropy alloy and an aluminum-based catalyst support, wherein the catalyst is present in the form of a first plurality of particles, wherein the first plurality of particles are submicron in size, and wherein the high-entropy alloy has an entropy S such that S ≥ 12.47 J·K -1 ·mol -1 The high-entropy alloy comprises at least five of the following: iron, cobalt, manganese, nickel, molybdenum, copper, zinc, titanium, chromium, vanadium, aluminum, gallium, ruthenium, rhodium, palladium, silver, indium, tungsten, rhenium, iridium, platinum, gold, and bismuth; and the hydrocarbon is reacted with the catalyst to produce solid carbon and a product gas, wherein the product gas includes hydrogen.

[0008] A third non-limiting example method of this disclosure may include: introducing hydrocarbons into a reactor, wherein the reactor contains a catalyst, wherein the reactor is substantially free of oxygen and water, wherein the catalyst comprises a high-entropy alloy and an aluminum-based catalyst support, wherein the catalyst is present in the form of a first plurality of particles, wherein the first plurality of particles are submicron in size, and wherein the high-entropy alloy has an entropy S such that S ≥ 12.47 J·K -1 ·mol -1 The high-entropy alloy is substantially composed of iron, cobalt, manganese, nickel, and a) molybdenum, b) copper, or c) molybdenum and copper; and the hydrocarbon is reacted on the catalyst to produce solid carbon and hydrogen.

[0009] The various embodiments and any combinations of embodiments disclosed herein may be used in another embodiment consistent with this disclosure. These and other aspects and features can be understood from the following description of certain embodiments presented herein, based on this disclosure, the accompanying drawings, and the claims. Attached Figure Description

[0010] Figure 1 This is a flowchart of a non-limiting example method for producing hydrogen from hydrocarbons according to this disclosure.

[0011] Figure 2 This is a diagram of a non-limiting example system for producing hydrogen from hydrocarbons according to this disclosure.

[0012] Figure 3 It is a graph of methane conversion efficiency according to an example of this disclosure.

[0013] Figure 4 This is an enlarged image of an example based on this disclosure.

[0014] Figure 5 It is a graph of methane conversion efficiency according to an example of this disclosure.

[0015] Figure 6 This is an enlarged image of an example based on this disclosure.

[0016] Figure 7 It is a graph of methane conversion efficiency according to an example of this disclosure. Detailed Implementation

[0017] Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. For consistency, similar elements may be denoted by similar reference numerals in the various drawings. Furthermore, numerous specific details are set forth in the following detailed description of embodiments of the present disclosure to provide a more thorough understanding of the claimed subject matter. However, it will be apparent to those skilled in the art that the embodiments disclosed herein can be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description. Additionally, it will be apparent to those skilled in the art that the scale of the elements presented in the drawings may vary without departing from the scope of the present disclosure.

[0018] The embodiments of this disclosure generally relate to the production of hydrogen.

[0019] This disclosure provides methods and systems for producing hydrogen from hydrocarbons (e.g., methane, crude oil, gasoline, etc.) using pyrolysis, with little or no release of carbon dioxide or carbon monoxide. Conventional hydrogen production from hydrocarbons typically releases significant amounts of carbon dioxide and / or carbon monoxide. The methods and systems of this disclosure limit this release by using a reactor environment in which little or no oxygen or water is present, as such oxygen or water would theoretically react to form carbon dioxide and / or carbon monoxide. This disclosure allows for the production of hydrogen from hydrocarbons in a manner with low or no greenhouse gas emissions, thereby increasing the sustainability of the produced hydrogen. To carry out said hydrogen production, the methods and systems of this disclosure may include reactor systems having a catalyst, said catalyst comprising a high-entropy alloy catalyst.

[0020] As used herein, “catalyst,” “catalytic,” “catalytic,” and their grammatical variations refer to a compound (or a method of using such a compound) that increases the rate of a chemical reaction without being consumed during the reaction. A catalyst may comprise an active catalyst and additional components, such as a second phase, a catalyst support, a catalyst promoter, etc., or any combination thereof.

[0021] As used herein, "high-entropy alloy catalyst" refers to a catalyst containing a high-entropy alloy. High-entropy alloy catalysts may contain additional components as described above for catalysts.

[0022] Unbound by theory, the catalyst disclosed herein can react with hydrocarbons according to a pyrolysis reaction, as shown in Formula 1 below.

[0023] C n H m → nC + (m / 2)H2 Equation 1

[0024] Where n is greater than or equal to 1, and m is less than or equal to 2n+2. It should be noted that the reaction in Equation 1 is preferably endothermic. As shown in the figure, the pyrolysis reaction does not include oxygen or water and does not produce carbon dioxide or carbon monoxide.

[0025] As a non-limiting example, a catalyst can produce hydrogen from methane via a pyrolysis reaction in the absence of oxygen and water, as shown in Equation 2 below.

[0026] CH4 → C + 2H2 (Equation 2)

[0027] Unbound by theory, the enthalpy of reaction in Equation 2 is approximately +75 kJ / mol, indicating that it is endothermic.

[0028] A flowchart of a non-limiting example method for producing hydrogen from hydrocarbons according to this disclosure is shown below. Figure 1 Method 100 includes providing a catalyst to a reactor (box 102). After the catalyst introduction 102, a purge gas may be introduced into the reactor (box 104). When the purge gas is introduced 104, the reactor may be started to be heated (box 106). It should be noted that the heating of the reactor 106 typically occurs during the purging step and is typically continuous to maintain the heat of the reactor during the reaction process. After purging 104, when the reactor reaches the desired reaction temperature, hydrocarbons may be introduced into the reactor (box 108). The introduction of hydrocarbons 108 allows the hydrocarbons to interact in the presence of the catalyst (box 110) and form a product comprising solid carbon and a product gas, said product gas including hydrogen. Solid carbon may be separated from the product gas and collected (box 112), and hydrogen may be separated from the product gas (box 114). After hydrogen separation 114, hydrogen may be delivered for further use and / or processing. In some cases, solid carbon may be continuously removed during the reaction process.

[0029] Purging the reactor is used to remove any oxygen or water from it. The reactor may be purged with a purge gas before the introduction of hydrocarbons. Examples of purge gases include, but are not limited to, nitrogen, argon, and any combination thereof. Purging can occur at any suitable flow rate and can depend on factors including, but not limited to, reactor size, reactor geometry, ambient temperature, and any combination thereof. Purging can be sustained for a duration, for example, from 5 minutes to 5 hours (or 5 minutes to 3 hours, or 5 minutes to 90 minutes, or 10 minutes to 90 minutes, or 15 minutes to 90 minutes, or 5 minutes to 60 minutes, or 10 minutes to 60 minutes, or 15 minutes to 60 minutes, or 5 minutes to 30 minutes, or 10 minutes to 30 minutes, or 15 minutes to 30 minutes).

[0030] The reactor can be operated at any suitable temperature and pressure. Preferably, the reactor can be operated at temperatures ranging from 300°C to 1200°C (or 300°C to 1000°C, or 400°C to 1000°C, or 400°C to 900°C, or 500°C to 900°C, or 500°C to 800°C, or 600°C to 800°C, or about 500°C, or about 600°C, or about 700°C, or about 800°C, or 450°C to 550°C, or 550°C to 650°C, or 650°C to 750°C, or 750°C to 850°C). Preferably, the reactor can be operated at pressures ranging from 1 bar to 25 bar (or 1 bar to 20 bar, or 1 bar to 10 bar, or 5 bar to 15 bar, or 10 bar to 20 bar, or 15 bar to 25 bar, or 0.1 bar to 25 bar). Temperatures and pressures outside the aforementioned ranges were also considered.

[0031] The reactor can output product gas. It should be noted that, in addition to product gas and solid carbon, other impurities may form in the reactor and may mix with the product gas, solid carbon, or both. Solid carbon can be in any form, including but not limited to amorphous carbon, carbon nanotubes, nanofibers, graphite, graphene, etc., or any combination thereof. Separating hydrogen and solid carbon from the product gas may include passing hydrogen through a separation system, which may include a solid carbon collection unit, a gas separation unit, or a combination thereof. The solid carbon collection unit may include any suitable separation unit, including but not limited to, for example, any suitable form of cyclone separator, etc., or any combination thereof. The gas separation unit may include any suitable gas separation unit, including but not limited to, for example, a separation membrane. The separation membrane can separate hydrogen and solid carbon from any impurities or any combination thereof. Any suitable separation membrane can be used.

[0032] Any reactor described in any of the above systems may include a heating system to heat the reactor. The reactor may be heated at any suitable rate, including but not limited to, heating rates of, for example, from 1°C / min to 30°C / min (or 1°C / min to 20°C / min, or 1°C / min to 15°C / min, or 1°C / min to 10°C / min, or 5°C / min to 10°C / min, or about 5°C / min, or about 10°C / min, or about 15°C / min, or about 20°C / min). The reactor's heating system may require a large heat load, therefore the use of a heating method with low or no greenhouse gas emissions may be preferred, although any suitable heating method may be used. Suitable heating methods used in this disclosure may include, but are not limited to, hydrocarbon heating, induction heating, plasma heating (e.g., microwave plasma, etc., or any combination thereof), microwave heating, solar furnace heating, radiant heating, etc., or any combination thereof.

[0033] Hydrocarbon heating may involve burning hydrocarbons (e.g., natural gas, gasoline, etc., or any combination thereof) to provide thermal energy. It should be noted that any suitable heat-conducting material (e.g., heat transfer fluid, etc., or any combination thereof) can be used to transfer thermal energy from the combustion of hydrocarbons to the reactor.

[0034] Heating systems can include induction heating. In an induction heating system, an electric current can flow through a metal coil to electromagnetically heat the metal within the catalyst. Induction heating can improve heating efficiency by reducing waste heat loss, thereby increasing the reactor's energy efficiency.

[0035] Plasma heating can include a system in which heat is provided to generate plasma by heating gases within a reactor. Microwave heating can include a system in which metal coils are used to generate microwave radiation to heat materials within a reactor. Solar furnace heating can include a system that utilizes thermal energy from solar radiation and delivers this solar radiation heat energy to a reactor to heat the reactor.

[0036] For any of the above-mentioned heating methods that require electrical energy (e.g., microwave heating, radiation heating, induction heating, etc.), the electrical energy used to heat the reactor can come from sources with low or no greenhouse gas emissions (e.g., solar, wind, hydropower, nuclear, etc. or any combination thereof).

[0037] catalyst

[0038] The catalysts used in this disclosure may comprise high-entropy alloy catalysts, such as those previously described herein.

[0039] As used in this article, "high-entropy alloy" refers to a mixed configuration entropy S ≥ 12.47 J·K. -1 ·mol -1Catalytic compositions and / or catalytic compositions comprising metal alloys, wherein the metal alloys are composed of five or more metal elements, each having a concentration of 0.1 atomic percentage (at%) to 50 at%.

[0040] The mixed configuration entropy S of a composition (e.g., an alloy) containing more than one type of element is typically calculated according to Equation 3 below.

[0041] Formula 3

[0042] Where R is the molar gas constant (approximately 8.314 J·K). -1 ·mol -1 ), and x i It is the mole fraction of a single element type (e.g., a single metal). For alloys with equimolar ratios of elements, Equation 1 can be simplified to Equation 4 below.

[0043] Formula 4

[0044] Where n is the number of individual element types present in the alloy.

[0045] An alloy can be considered a high-entropy alloy if its entropy S is greater than the entropy of a mixed configuration with 5 or more equimolar types of compounds. If the number of equimolar types of elements present is 5, then S = 1.61R. Table 1 lists exemplary configurational entropies of equiatomic alloys with up to and including 10 constituent elements. Therefore, if an alloy has an entropy S such that S ≥ 1.5R, then, equivalently, S ≥ 12.47 J·K. -1 ·mol -1 If so, the alloy can be considered a high-entropy alloy.

[0046] Table 1. Configuration entropy of equiatomic alloys with constituent elements

[0047] N 1 2 3 4 5 6 7 8 9 10 ΔS 0 0.69R 1.1R 1.39R 1.61R 1.79R 1.95R 2.08R 2.20R 2.30R

[0048] The high-entropy alloy suitable for the catalyst used in hydrogen production according to this disclosure may contain metals, including but not limited to cobalt, chromium, iron, manganese, nickel, aluminum, molybdenum, copper, zinc, zirconium, ruthenium, rhodium, palladium, silver, tungsten, rhenium, iridium, platinum, gold, cerium, ytterbium, tin, etc., or any combination thereof. It should be noted that the high-entropy alloy may contain five or more (or 5, or 5 to 30, or 5 to 6, or 5 to 7, or 5 to 8, or 5 to 9, or 5 to 10, or 5 to 15, 5 to 20, or 5 to 25) suitable metals in any combination. Each metal in the high-entropy alloy may account for 0.1 at% to 50 at% (or 0.1 at% to 20 at%, or 0.1 at% to 40 at%, or 0.1 at% to 25 at%, or 1 at% to 25 at%, or 5 at% to 35 at%) of the high-entropy alloy.

[0049] High-entropy alloys may have metallic crystal structures, including but not limited to face-centered cubic (FCC), body-centered cubic (BCC), hexagonal close-packed (HCP) structures, or any combination thereof. Furthermore, the high-entropy alloys of this disclosure may have amorphous structures or structures comprising a combination of crystalline metallic and amorphous components.

[0050] Incorporating high-entropy alloys into catalysts can provide additional characteristics, including increased activity and reduced adsorption energy. Unbound by theory, it is believed that the presence of additional high-entropy elements, which are believed to contribute to high-entropy catalysts, allows for additional atomic arrangements on the catalyst surface, thereby enabling increased adsorption onto the catalyst surface.

[0051] High-entropy alloys can be manufactured using synthesis in the solid, liquid, gas, or any combination thereof. The synthesis methods used can include any suitable method for manufacturing high-entropy alloys, including but not limited to wet chemical methods, sol-gel autocombustion, spray pyrolysis, carbothermal shock synthesis, hydrothermal methods, pulsed laser ablation, mechanical polishing, arc melting, induction melting, metal spraying, molecular beam epitaxy, atomic layer deposition, chemical vapor deposition, pulsed laser deposition, and any combination thereof.

[0052] The catalyst may include a catalyst support. As used herein, "catalyst support" and its grammatical variations refer to a compound or material to which the catalyst is attached to provide additional characteristics. The catalyst support used in this disclosure may comprise any suitable catalyst support material, including but not limited to metals, metal oxides, zeolites, carbon black, second phases, etc., or any combination thereof. Suitable metal oxides may include, but are not limited to, Al2O3, SiO2, MgO, TiO2, Fe3O4, Fe2O3, ZrO2, CeO2, lanthanide oxides (e.g., Er2O3), etc., or any combination thereof. The catalyst may comprise 0.0001 at% to 80 at% (or 0.0001 at% to 20 at%, or 0.0001 at% to 40 at%) of catalyst support. The catalyst support may be an internal catalyst support, an external catalyst support, or any combination thereof. As used herein, "internal catalyst support" refers to a catalyst support embedded in a high-entropy alloy structure. As a non-limiting example, a catalyst with an internal catalyst support may comprise silica nanoparticles, wherein more than one silica nanoparticle is on the surface of a single catalyst particle and / or within a portion of a single catalyst particle, thus constituting an internal catalyst support. As used herein, “external catalyst support” refers to a catalyst support located outside the structure of a high-entropy alloy. As a non-limiting example, a catalyst with an external catalyst support may comprise an Au / TiO2 catalyst, wherein Au performs the catalytic action and TiO2 forms large particles outside the Au, thus TiO2 acts as an external catalyst support.

[0053] When added to a catalyst, a catalyst support can be used to improve catalytic efficiency. Catalyst supports can provide characteristics to the catalyst, such as increased alloy dispersibility, improved sintering resistance, increased reactant adsorption rates, or any combination thereof. Catalyst supports can also prevent impurity deposition (e.g., coke formation) on the catalyst surface, thereby maintaining increased catalytic activity over a longer period. Catalyst supports function through chemical, physical, or chemical and physical interactions with other components of the catalyst, the reaction substrate, or any combination thereof.

[0054] The catalyst may contain a catalyst promoter. As used herein, "catalyst promoter" and its grammatical variations refer to a compound provided together with the catalyst to increase the catalytic activity of the catalyst. The catalyst promoter used in this disclosure may contain any suitable catalyst promoter material, including but not limited to metals, metal oxides, second phases, etc., or any combination thereof. Suitable catalyst promoter materials may include, but are not limited to, alkali metals (e.g., lithium, sodium, potassium, cesium, francium, or any combination thereof), alkaline earth metals (e.g., calcium, magnesium, barium, or any combination thereof), transition metals (e.g., iron, cobalt, manganese, magnesium, nickel, molybdenum, copper, palladium, platinum, rhenium, or any combination thereof), post-transition metals (e.g., aluminum, gallium, or any combination thereof), cerium compounds (e.g., cerium, cerium oxide (e.g., Ce₂O₃, CeO₂, or any combination thereof) or any combination thereof), lanthanides (e.g., lanthanum, neodymium, or any combination thereof), metal oxides (e.g., MgO, Ca₂SiO₄, CaO, or any combination thereof), germanium compounds, etc., or any combination thereof. The catalyst promoter may comprise 0.0001 at% to 50 at% (or 0.0001 at% to 20 at%, or 0.0001 at% to 40 at%) of the catalyst. The catalyst promoter may be an internal catalyst promoter, an external catalyst promoter, or any combination thereof. As used herein, "internal catalyst promoter" refers to a catalyst promoter embedded within the high-entropy alloy structure. As used herein, "external catalyst promoter" refers to a catalyst promoter located outside the structure of the high-entropy alloy.

[0055] The catalyst promoters used in this disclosure can be used as chemical promoters, structural promoters, or any combination thereof. When used as chemical promoters, catalyst promoters can improve catalyst efficiency by altering the electron distribution on the catalyst surface (not bound by theory). When used as structural promoters, catalyst promoters can modify the mechanical properties of the catalyst, such as increasing sintering resistance. Catalyst promoters can also provide additional characteristics, such as increasing the selectivity of the catalyst for specific reactants. Not bound by theory, catalyst promoters can increase the adsorption and chemisorption of specific reactants at the active sites of the catalyst, thereby increasing selectivity. Catalyst promoters can also increase the durability of the catalyst.

[0056] It should be noted that in some embodiments, the catalyst promoter may be a metal, in other embodiments it may be a catalyst support, and in other embodiments it may comprise a high-entropy alloy. In other words, a single metal may provide catalytic activity in some embodiments, serve as a catalyst promoter in other embodiments, and serve as a catalyst support in other embodiments. Without being bound by theory, the function of a metal can be determined by other components in the catalyst and its interactions with other elements and compounds. As an illustrative and non-limiting example, in a first case, the catalyst may comprise a high-entropy alloy, wherein the high-entropy alloy comprises nickel, aluminum, magnesium, copper, and zinc, and wherein the catalyst further comprises zirconium as an internal catalyst promoter. Continuing with the non-limiting example, in a second case, the catalyst may comprise a high-entropy alloy, wherein the high-entropy alloy comprises nickel, aluminum, rhodium, silver, and palladium, and wherein the catalyst further comprises copper as an internal catalyst promoter. Continuing with the non-limiting example, in a third case, the catalyst may comprise a high-entropy alloy, wherein the high-entropy alloy comprises nickel, aluminum, zirconium, palladium, and zinc, and wherein the catalyst further comprises copper as a catalyst support. In the foregoing non-limiting examples, depending on the embodiment, copper may comprise a high-entropy alloy, may serve as a catalyst promoter, or may serve as a catalyst support.

[0057] The catalysts described herein may further comprise a second phase. The second phase can interact with any component of the catalyst and can provide characteristics such as increased catalytic activity. As mentioned above, the second phase or portions thereof can be used as catalyst promoters, catalyst supports, or any combination thereof. The second phase may comprise any suitable composition, including but not limited to intermetallic phases, Lavren phases, carbide phases, boride phases, boron carbide phases, nitride phases, silicide phases, aluminide phases, oxide phases (e.g., MgO, Al₂O₃, or any combination thereof), phosphide phases, phosphate phases, sulfide phases, sulfate phases, hydride phases, hydrate phases, carbonitride phases, graphene phases, graphene oxide phases, nanotube phases, graphite phases, or any combination thereof.

[0058] The catalyst disclosed herein may comprise a high-entropy alloy. The high-entropy alloy may exist in the form of multiple particles. These multiple high-entropy alloy particles may be submicron in size.

[0059] As used in this article, “submicron size” and its grammatical variations refer to particles that can have an average size of about 1 nanometer (nm) to about 999 micrometers (μm).

[0060] The high-entropy alloy particles of this disclosure preferably have an average size of 1 nm to 15 μm (or 1 nm to 10 μm, or 1 nm to 999 nm, or 1 μm to 10 μm), or more preferably 1 nm to 10 μm, or 1 nm to 1 μm, or 1 nm to 100 nm, or even more preferably 1 nm to 50 nm, or most preferably 1 nm to 20 nm. This preferred high-entropy alloy particle size allows for optimized surface area for adsorbing reactants and subsequent catalytic reactions according to this disclosure. The average size of a plurality of high-entropy alloy particles can be defined as the average width, length, height, diameter, or any combination thereof of the particles. The high-entropy alloy particles can be of any shape, including but not limited to spheres, cubes, triangles, oblong shapes, irregular shapes, or any combination thereof.

[0061] The catalyst itself (e.g., comprising a high-entropy alloy and a catalyst support) may also exist in the form of multiple particles, each comprising one or more high-entropy alloy particles. The multiple catalyst particles may be submicron in size. The multiple catalyst particles preferably have an average size of 1 nm to 500 μm (or 1 nm to 10 μm, or 1 nm to 999 nm, or 1 μm to 999 μm), or preferably have an average size of 1 nm to 100 μm, or 50 nm to 125 μm, or 100 nm to 10 μm, or more preferably 100 nm to 5 μm, or most preferably 200 nm to 2 μm. This preferred catalyst particle size allows for optimized surface area for catalytic reactions according to this disclosure. The average size of the multiple catalyst particles can be defined as the average width, length, height, diameter, or any combination thereof of the particles. The catalyst particles can be of any shape, including but not limited to spheres, cubes, triangles, oblongs, irregular shapes, or any combination thereof. The multiple catalyst particles can be formed in any suitable shape and size as catalyst beads, catalyst pellets, or any combination thereof.

[0062] Unbound by theory, such particle sizes (e.g., catalyst particles and / or high-entropy alloy particles) allow for increased interparticle distances and stronger interactions with the catalyst support, thereby mitigating catalyst particle agglomeration and / or metal sintering of the high-entropy alloy. Furthermore, the optimized surface area provided by the particle sizes disclosed herein can further promote reactions with high conversion efficiency and can provide volumetric space for carbon products, thus increasing the carbon tolerance of the catalysts disclosed herein. As a result, both the activity and stability of the catalysts disclosed herein can be increased due to the particle sizes disclosed herein.

[0063] The catalyst may further include an anti-sticking additive. The anti-sticking additive prevents carbon and / or any other impurities formed during the reaction from adhering to the catalyst, potentially maintaining catalyst activity over extended periods, reducing the need for cleaning or catalyst replacement, and thus lowering costs. The anti-sticking additive may include any suitable material, including but not limited to magnesium silicate, borosilicates, borates, alumina, silica, titanium dioxide, zirconium oxide, etc., or any combination thereof.

[0064] The catalyst can preferably be a supported metal catalyst comprising a high-entropy alloy. The high-entropy alloy can preferably comprise at least five metals from iron, cobalt, manganese, nickel, molybdenum, copper, zinc, titanium, chromium, vanadium, aluminum, gallium, ruthenium, rhodium, palladium, silver, indium, tungsten, rhenium, iridium, platinum, gold, bismuth, etc., or any combination thereof. The high-entropy alloy can preferably consist substantially of iron, cobalt, manganese, copper, and nickel, or it can preferably consist substantially of iron, cobalt, manganese, molybdenum, and nickel. The high-entropy alloy can preferably contain metals in equimolar proportions. Exemplary supported metal catalysts comprising high-entropy alloys include, for example, but not limited to, Al₂O₃-supported FeCoMnNiCu catalysts, Al₂O₃-supported FeCoMnNiMo catalysts, etc., or any combination thereof. Without being bound by theory, supported high-entropy alloy metal catalysts can provide increased catalyst efficiency and functionality due to factors including, but not limited to, the metal content and distribution of the catalyst, the composition of the catalyst support, pore size distribution, surface area, physical integrity, etc., or any combination thereof.

[0065] It should be noted that the catalyst can be further processed to modify its characteristics, including but not limited to size, shape, etc., or any combination thereof. Exemplary further processing for catalysts is known to those skilled in the art. As an example, the catalyst may be ball-milled, including using a zirconium oxide media (e.g., yttrium-stabilized zirconium oxide). The ball milling of the catalyst can be performed at any suitable rotational frequency and for any suitable duration. The ball milling of the catalyst is preferably performed at a rotational speed of 100 rpm to 2000 rpm (or 100 rpm to 1500 rpm, or 100 rpm to 1200 rpm, or 1000 rpm to 1200 rpm, or about 1100 rpm). The ball milling of the catalyst is preferably performed for a duration of 1 day to 20 days (or 1 day to 8 days, or 1 day to 5 days, or 1 day to 4 days, or 1 day to 2 days, or about 1 day).

[0066] During the reaction, the catalyst can be contained in the reactor in any suitable manner, including but not limited to catalyst beds (e.g., fluidized beds) or any combination thereof.

[0067] hydrocarbons

[0068] Hydrocarbons used to produce hydrogen can include any suitable hydrocarbons, such as, but not limited to, methane, ethane, propane, gasoline, kerosene, diesel fuel, residual oil, crude oil, or any combination thereof.

[0069] Hydrocarbons can be introduced into the reactor at any suitable pressure, temperature, and flow rate compatible with the reactor's reaction conditions. If the hydrocarbons are introduced in gaseous form, they may further contain an inert carrier gas (e.g., nitrogen, argon, etc., or any combination thereof). While in the reactor, the hydrocarbons can be catalyzed by a catalyst to form a product gas containing hydrogen and solid carbon.

[0070] hydrogen

[0071] The produced hydrogen can have any suitable purity, including 90 mol% to 99.99 mol% (40 mol% to 99.99 mol%, or 60 mol% to 99.99 mol%, or 80 mol% to 99.99 mol%, or 95 mol% to 99.99 mol%, or greater than 99.99 mol%). The produced hydrogen can be supplied at any suitable temperature and pressure. The pressure and temperature of the produced hydrogen can be affected by the pressure and temperature of the reactor or any other unit described herein. The produced hydrogen can then be directed to any suitable location, including but not limited to pipelines, storage tanks, railcar tanks, or any combination thereof.

[0072] system

[0073] Figure 2 A diagram of a non-limiting example system for producing hydrogen according to this disclosure is shown. System 200 includes a reactor 210 having a hydrocarbon feed 202h and a nitrogen feed 202n, and a heat supply 204 to the reactor 210. As described above, the reactor 210 may contain a catalyst. After processing through the reactor 210, the product gas stream 212 may enter one or more units for further processing, including a solid carbon collection unit 220 and a gas separation unit 230. The system may optionally include an online sampling device 240. A hydrogen product stream 250 containing the produced hydrogen can be provided through the solid carbon collection unit 220, the gas separation unit 230, and the optional online sampling device 240. As described above, the hydrogen product stream 250 can be directed to any suitable location.

[0074] The entire system can have any suitable conversion efficiency, including but not limited to 20% to 99.9% (or 20% to 60%, or 60% to 99.9%, or greater than 99.9%). As used herein, “conversion efficiency” refers to the ratio of the actual conversion of reactants to the theoretical stoichiometric conversion and can be expressed as a percentage (%). Using methane (CH4) as a non-limiting example, if 100% conversion efficiency is achieved, 1 mole of CH4 can produce 2 moles of hydrogen gas (H2). Continuing with the non-limiting example, the methane conversion efficiency (MCE) can be calculated using Equation 5 below.

[0075] MCE = (R 氢 / 2) / (R 氢 / 2 + R 未反应甲烷 ) * 100 Formula 5

[0076] Among them, R 氢 R is the amount of hydrogen produced at the outlet. 未反应甲烷 This is the amount of unreacted methane at the outlet. The system may include any suitable recirculation streams and devices not described herein for further improvement of conversion efficiency.

[0077] It should also be noted that the methods and systems disclosed herein may include operating the reactors described herein in any suitable manner, including any suitable configuration (e.g., parallel, series, etc. or combinations thereof) and any suitable mode of operation (e.g., continuous, batch, etc. or combinations thereof).

[0078] It should be understood that those skilled in the art should be able to utilize the benefits of this disclosure to implement the methods and systems described above. It should be noted that additional, non-limiting components may be used in the methods and systems for generating hydrogen described above. Such additional components will be familiar to those skilled in the art and may include, but are not limited to, valves, pumps, connectors, sensors, compressors, controllers, heat exchangers, sampling equipment (e.g., gas chromatographs), and any combination thereof.

[0079] Example

[0080] Example 1

[0081] A non-supported metallic alloy powder, MET-5003 (purchased from Matexcel), containing 99.9% pure FeCoNiCrMn, was used as the catalyst. The particle size of MET-5003 ranged from 15 µm to 53 µm. Approximately 20 g of MET-5003 powder was loaded into a vertical tubular reactor equipped with a quartz tube (22 mm inner diameter x 25 mm outer diameter x 530 mm length, with a #4 porosity sintered plate 200 mm from the bottom) measuring 1 inch in diameter and 530 mm in length. The quartz tube was then sealed at both ends with appropriate gas inlets and outlets. The system was purged with nitrogen to remove oxygen from the reactor environment. The reactor was then heated to the initial reaction temperature of 700 °C at a rate of 10 °C per minute while maintaining a nitrogen flow. Once the reactor reached the desired reaction temperature, the gas flow was switched to methane at a flow rate of 20 mL / min.

[0082] The waste gas, containing generated hydrogen, unreacted methane, and other potentially generated gases, was analyzed using online gas chromatography. The methane conversion efficiency percentage (%) is shown below. Figure 3 The graph is shown in the figure. Figure 3 As shown, the methane conversion efficiency is less than approximately 10%.

[0083] Example 2

[0084] A FeCoMnNiCu catalyst supported on Al2O3 was formed by ball milling 50 g of Al2O3, Fe, Co, Mn, Ni, and Cu (molar ratio of Al2O3:Fe:Co:Mn:Ni:Cu equal to 1:1:1:1:1:1) at 1100 rpm for 2 days at room temperature (approximately 25°C) using 150 g of 3 mm zirconia media (e.g., yttrium-stabilized zirconia) and 200 g of 1 mm zirconia media. The catalyst was separated using a 30-mesh sieve (catalyst IE1), and the catalyst sample was collected and examined under 1000x magnification. Figure 4 As shown, the average particle size of catalyst IE1 is approximately 1 μm to approximately 2 μm.

[0085] Approximately 20 g of catalyst IE1 was charged into a vertical tubular reactor equipped with a quartz tube (22 mm inner diameter x 25 mm outer diameter x 530 mm length, with a #4 porosity sintered plate 200 mm from the bottom) measuring 1 inch in diameter and 530 mm in length. Both ends of the quartz tube were sealed with appropriate gas inlets and outlets. The reactor environment was purged with nitrogen to remove oxygen. The reactor was then initially heated to a reaction temperature of 700°C at a rate of 10°C per minute while maintaining a nitrogen flow. Once the reactor reached the desired reaction temperature, the gas flow was switched to methane at a flow rate of 20 mL / min.

[0086] The waste gas, containing generated hydrogen, unreacted methane, and other potentially generated gases, was analyzed using online gas chromatography. Methane conversion efficiency (%) was calculated. Figure 5 The graph is shown in the figure. Figure 5 As shown, the methane conversion efficiency is between approximately 50% and approximately 65%.

[0087] Example 3

[0088] A FeCoMnNiMo catalyst supported on Al2O3 was formed by ball milling 50 g of Al2O3, Fe, Co, Mn, Ni, and Mo (molar ratio of Al2O3:Fe:Co:Mn:Ni:Mo equal to 1:1:1:1:1:1) at 1100 rpm for 2 days at room temperature (approximately 25°C) using 150 g of 3 mm zirconia media (e.g., yttrium-stabilized zirconia) and 200 g of 1 mm zirconia media. The catalyst was separated using a 30-mesh sieve (catalyst IE2), and catalyst samples were collected and examined under 1000x magnification. Figure 6 As shown, the average particle size of the catalyst IE2 is approximately 1 μm to 2 μm.

[0089] Approximately 20 g of IE2 catalyst was charged into a vertical tubular reactor equipped with a quartz tube (22 mm inner diameter x 25 mm outer diameter x 530 mm length, with a #4 porosity sintered plate 200 mm from the bottom) measuring 1 inch in diameter and 530 mm in length. Both ends of the quartz tube were sealed with appropriate gas inlets and outlets. The reactor environment was purged with nitrogen to remove oxygen. The reactor was then initially heated to a reaction temperature of 700°C at a rate of 10°C per minute while maintaining a nitrogen flow. Once the reactor reached the desired reaction temperature, the gas flow was switched to methane at a flow rate of 20 mL / min.

[0090] The waste gas, containing generated hydrogen, unreacted methane, and other potentially generated gases, was analyzed using online gas chromatography. Methane conversion efficiency (%) was calculated. Figure 7 The graph is shown in the figure. Figure 7 As shown, the methane conversion efficiency is approximately 70%.

[0091] Additionally, solid carbon byproducts are collected after the reactions in Examples 2 and 3, for example. These solid carbon byproducts include a mixture of black carbon, nanotubes, and nanofibers.

[0092] Additional Examples

[0093] Example 1. A method comprising: introducing hydrocarbons into a reactor, wherein the reactor contains a catalyst, wherein the reactor is substantially free of oxygen and water, wherein the catalyst comprises a high-entropy alloy and a catalyst support, wherein the catalyst is present in the form of a first plurality of particles, wherein the first plurality of particles are submicron in size, wherein the high-entropy alloy has an entropy S such that S ≥ 12.47 J·K -1 ·mol -1 The high-entropy alloy comprises at least five of the following: iron, cobalt, manganese, nickel, molybdenum, copper, zinc, titanium, chromium, vanadium, aluminum, gallium, ruthenium, rhodium, palladium, silver, indium, tungsten, rhenium, iridium, platinum, gold, and bismuth; and the hydrocarbon is reacted on the catalyst to produce solid carbon and hydrogen.

[0094] Example 2. The method according to Example 1, wherein each metal in the high entropy alloy has a composition of 0.1 at% (atomic percentage) to 50 at% in the high entropy alloy.

[0095] Example 3. The method according to Example 1 or 2, wherein the catalyst is located in a fluidized bed within the reactor.

[0096] Example 4. The method according to any one of Examples 1 to 3 further includes: purging the reactor with an inert gas to remove oxygen, water, or a combination thereof before introducing the hydrocarbon.

[0097] Example 5. The method according to Example 4 further includes heating the reactor at least partially during purging of the reactor.

[0098] Example 6. The method according to Example 5, wherein the reactor is heated by hydrocarbon heating, induction heating, plasma heating, microwave heating, solar furnace heating, radiation heating, or any combination thereof.

[0099] Example 7. The method according to Example 6, wherein the electrical energy used to heat the reactor is derived from renewable energy sources.

[0100] Example 8. The method according to any one of Examples 1 to 7 further includes collecting the solid carbon.

[0101] Example 9. The method according to Example 8, wherein the collection uses a cyclone separator.

[0102] Example 10. The method according to any one of Examples 1 to 9 further includes separating the hydrogen from the solid carbon and the remaining hydrocarbons.

[0103] Example 11. The method according to Example 10, wherein the separation uses a separation membrane.

[0104] Example 12. The method according to any one of Examples 1 to 11, wherein the high-entropy alloy exists in the form of a second plurality of particles, wherein the second plurality of particles have an average size of 1 nm to 500 nm.

[0105] Example 13. The method according to any one of Examples 1 to 12, wherein the first plurality of particles have an average catalyst size of 0.2 μm to 5 μm.

[0106] Example 14. The method according to any one of Examples 1 to 13, wherein the catalyst support comprises Al2O3, and wherein the high-entropy alloy comprises FeCoMnNiCu, FeCoMnNiMo, or any combination thereof.

[0107] Example 15. The method according to any one of Examples 1 to 13, wherein the high-entropy alloy comprises iron, cobalt, manganese, nickel and a) molybdenum, b) copper or c) molybdenum and copper; and wherein iron, cobalt, manganese, nickel and molybdenum and / or copper are in equimolar concentrations.

[0108] Example 16. The method as described in any one of Examples 1 to 15, wherein the temperature of the reactor is 300°C to 1200°C.

[0109] Example 17. A method comprising: purging a reactor with an inert gas to remove oxygen, water, or a combination thereof, wherein the inert gas includes nitrogen, argon, or any combination thereof; introducing a hydrocarbon into the reactor, wherein the reactor contains a catalyst, wherein the catalyst comprises a high-entropy alloy and an aluminum-based catalyst support, wherein the catalyst is present in the form of a first plurality of particles, wherein the first plurality of particles are submicron in size, wherein the high-entropy alloy has an entropy S such that S ≥ 12.47 J·K -1 ·mol -1 The high-entropy alloy comprises at least five of the following: iron, cobalt, manganese, nickel, molybdenum, copper, zinc, titanium, chromium, vanadium, aluminum, gallium, ruthenium, rhodium, palladium, silver, indium, tungsten, rhenium, iridium, platinum, gold, and bismuth; and the hydrocarbon is reacted with the catalyst to produce solid carbon and gas, wherein the gas comprises hydrogen.

[0110] Example 18. The method according to Example 17, wherein the hydrocarbon includes methane, ethane, propane, gasoline, kerosene, diesel fuel, residual oil, crude oil, or any combination thereof.

[0111] Example 19. A method comprising: introducing hydrocarbons into a reactor, wherein the reactor contains a catalyst, wherein the reactor is substantially free of oxygen and water, wherein the catalyst comprises a high-entropy alloy and an aluminum-based catalyst support, wherein the catalyst is present in the form of a first plurality of particles, wherein the first plurality of particles are submicron in size, wherein the high-entropy alloy has an entropy S such that S ≥ 12.47 J·K -1 ·mol -1 The high-entropy alloy is substantially composed of iron, cobalt, manganese, nickel, and a) molybdenum, b) copper, or c) molybdenum and copper; and the hydrocarbon is reacted on the catalyst to produce solid carbon and hydrogen.

[0112] Example 20. The method according to Example 19, wherein iron, cobalt, manganese, nickel, and molybdenum and / or copper are in equimolar concentrations.

[0113] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that when the terms “comprising,” “containing,” and / or “including,” and variations thereof are used in this specification, they specify the presence of the stated feature, integral, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, and / or components.

[0114] The directional terms used herein are for convention and reference purposes only and should not be construed as restrictive. However, it should be recognized that these terms may be used by reference to the operator or user. Therefore, no limitation is implied or inferred. Furthermore, the use of ordinal numbers (e.g., first, second, third, etc.) is for distinction rather than counting. For example, the use of "third" does not necessarily imply a corresponding "first" or "second". In addition, if used herein, the terms "coupled" or "coupled to" or "connected" or "attached" or "attached to" may indicate the establishment of a direct or indirect connection, and are not limited to either, unless expressly stated otherwise.

[0115] While several exemplary embodiments have been described in this disclosure, those skilled in the art will understand that various changes can be made and elements can be substituted with equivalents without departing from the spirit and scope of the invention. Furthermore, those skilled in the art will understand that many modifications will adapt particular instruments, situations, or materials to embodiments of this disclosure without departing from the essential scope of this disclosure. Therefore, the invention is not limited to the specific embodiments disclosed or the best mode for carrying out the invention, but rather will include all embodiments falling within the scope of the appended claims. Moreover, references in the appended claims to means or systems or components of means or systems adapted to, arranged to, capable of, configured to, enable, operable to, or operated to perform a particular function include the means, system, or component, whether or not it or the particular function is activated, turned on, or unlocked, provided that the means, system, or component is so configured, arranged, capable of, operable to, or operated.

Claims

1. A method comprising: Hydrocarbons are introduced into the reactor. The reactor contains a catalyst. The reactor is essentially free of oxygen and water. The catalyst comprises a high-entropy alloy and a catalyst support. The catalyst exists in the form of a first plurality of particles. Among them, the first plurality of particles are submicron in size. The high-entropy alloy has an entropy S such that S ≥ 12.47 J·K. -1 ·mol -1 ,and The high-entropy alloy comprises at least five of the following: iron, cobalt, manganese, nickel, molybdenum, copper, zinc, titanium, chromium, vanadium, aluminum, gallium, ruthenium, rhodium, palladium, silver, indium, tungsten, rhenium, iridium, platinum, gold, and bismuth; and The hydrocarbon is reacted on the catalyst to produce solid carbon and hydrogen.

2. The method according to claim 1, wherein, The composition of each metal in the high-entropy alloy is from 0.1 at% (atomic percentage) to 50 at%.

3. The method according to any one of the preceding claims, wherein, The catalyst is located in a fluidized bed within the reactor.

4. The method according to any one of the preceding claims further includes: The reactor is purged with an inert gas to remove oxygen, water, or a combination thereof before the hydrocarbon is introduced.

5. The method of claim 4, further comprising heating the reactor during purging, wherein, The reactor is heated by hydrocarbon heating, induction heating, plasma heating, microwave heating, solar furnace heating, radiation heating, or any combination thereof.

6. The method according to any one of the preceding claims further includes collecting the solid carbon.

7. The method according to claim 6, wherein, The collection uses a cyclone separator.

8. The method according to any one of the preceding claims further comprises using a separation membrane to separate the hydrogen from the solid carbon and the remaining hydrocarbons.

9. The method according to any one of the preceding claims, wherein, The high-entropy alloy exists in the form of a second plurality of particles, wherein the second plurality of particles have an average size of 1 nm to 500 nm.

10. The method according to any one of the preceding claims, wherein, The first plurality of particles have an average catalyst size of 0.2 µm to 5 µm.

11. The method according to any one of the preceding claims, wherein, The catalyst support comprises Al2O3, and the high-entropy alloy comprises FeCoMnNiCu, FeCoMnNiMo, or any combination thereof.

12. The method according to any one of the preceding claims, wherein, The high-entropy alloy comprises iron, cobalt, manganese, nickel, and: a) Molybdenum, b) Copper, or c) Molybdenum and copper; and Among them, iron, cobalt, manganese, nickel, and molybdenum and / or copper are in equimolar concentrations.

13. The method according to claim 1, comprising: Before introducing the hydrocarbon into the reactor, the reactor is purged with an inert gas to remove oxygen, water, or a combination thereof, wherein the inert gas includes nitrogen, argon, or any combination thereof; The catalyst support is an aluminum-based catalyst support.

14. The method according to any one of the preceding claims, wherein, The hydrocarbons include methane, ethane, propane, gasoline, kerosene, diesel fuel, residual oil, crude oil, or any combination thereof.

15. The method according to claim 1, in, The high-entropy alloy is basically composed of iron, cobalt, manganese, nickel, and... a) Molybdenum, b) Copper, or c) Composed of molybdenum and copper.

16. The method according to claim 15, wherein, Iron, cobalt, manganese, nickel, and molybdenum and / or copper are in equimolar concentrations.