Ammonia decomposition catalyst including porous alumina support for catalyst coating and method for manufacturing the same

Abstract

The present invention provides a method for manufacturing an ammonia decomposition catalyst comprising the steps of: manufacturing an alumina carrier by extruding a dough prepared by mixing 20 to 80 parts by weight of alumina, 5 to 40 parts by weight of an organic binder, 2 to 15 parts by weight of an inorganic binder, and 10 to 20 parts by weight of a pore-forming agent with water; and coating the alumina carrier with a catalyst slurry containing a catalytic active component.

Description

Technology Field

[0001] The present invention relates to an ammonia decomposition catalyst comprising a porous alumina carrier having excellent strength and catalyst coating properties, and a method for manufacturing the same. Background Technology

[0002] Recently, due to the depletion of fossil fuels and environmental pollution issues, there is a high demand for new and renewable energy, and hydrogen is attracting attention as a means to meet this need.

[0003] Unlike fossil fuels, hydrogen is a clean energy source that emits no carbon dioxide and releases water as a byproduct; therefore, active research is underway on technologies to utilize hydrogen as fuel, and research on technologies to produce or utilize hydrogen to ensure a stable supply is also being conducted.

[0004] While methods have been proposed to compress or liquefy hydrogen and store it in a storage device, and then supply the hydrogen stored in the storage device, methods have also been proposed to store hydrogen using materials capable of storing hydrogen and then generate and supply the stored hydrogen. Specifically, methods using metal hydrides, methods using adsorption, desorption / absorbents / carbon, and chemical hydrogen storage methods have been proposed.

[0005] Among these, chemical hydride methods with high hydrogen storage density are attracting attention. In particular, since ammonia can store large amounts of hydrogen and maintain a stable state at room temperature, a plan to use ammonia as a hydrogen source is being proposed as a method for efficiently storing and transporting hydrogen.

[0006] In other words, ammonia can be an efficient hydrogen carrier because it can store 120 kg of hydrogen per cubic meter and has a very low fire risk due to its high autoignition temperature of 651°C. Furthermore, since ammonia has been used for industrial purposes, there is an economic advantage in being able to utilize existing ammonia infrastructure, so the method of producing hydrogen through the decomposition of ammonia is attracting attention as a realistic solution.

[0007] Since the process of decomposing ammonia into hydrogen and nitrogen is an endothermic process, energy is required to produce (or generate) hydrogen from ammonia, and specifically, hydrogen can be generated from ammonia through a reaction such as the chemical formula below.

[0008] [Chemical Formula]

[0009] 2NH3→ N2+ 3H2, △H=46.22 kJ / mol of NH3

[0010] There is a need for technology to reduce the energy consumption required when decomposing ammonia to generate hydrogen. Accordingly, Korean Patent Publication No. 10-2021-0147910, Korean Patent Publication No. 10-2021-0052938, and Korean Patent Publication No. 10-2019-0087810 disclose catalyst technology that uses ruthenium (Ru) as the active component of a catalyst to decompose ammonia and generate hydrogen.

[0011] However, as ruthenium (Ru) is a precious metal that is expensive and rare, there is a demand for low-cost non-precious metal catalysts that can replace it. In response to this demand, Korean Patents No. 10-2013-0062902, No. 10-2011-0055722, and No. 10-2022-0034652 disclose catalyst technologies containing non-precious metal active components, including nickel.

[0012] In addition, there is still a demand for catalyst technology with simple manufacturing processes and high efficiency and durability for the mass production of non-precious metal catalysts. Prior art literature

[0013] (Patent Document 0001) KR 10-2013-0062902 A(Patent Document 0002) KR 10-2021-0147910 A(Patent Document 0003) KR 10-2015-0058219 A(Patent Document 0004) KR 10-2011-0055722 A(Patent Document 0005) KR 10-2023-0071317 A(Patent Document 0006) KR 10-2013-0062902 A(Patent Document 0007) KR 10-2011-0055722 A(Patent Document 0008) KR 10-2022-0034652 A The problem to be solved

[0014] The present invention aims to provide an ammonia decomposition catalyst having excellent strength and catalyst coating properties, and performance equivalent to or better than that of conventional catalysts even with a small amount of catalytic active material, and a method for manufacturing the same. means of solving the problem

[0015] To solve the above problem, the present invention provides a method for manufacturing an ammonia decomposition catalyst comprising the steps of: manufacturing an alumina carrier by extruding a dough prepared by mixing 20 to 80 parts by weight of alumina, 5 to 40 parts by weight of an organic binder, 2 to 15 parts by weight of an inorganic binder, and 10 to 20 parts by weight of a pore-forming agent with water; and coating the alumina carrier with a catalyst slurry containing a catalytic active component.

[0016] According to one embodiment, the alumina carrier may be porous, having a porosity of 40 to 70% as alpha alumina.

[0017] According to one embodiment, the alumina carrier may have a pore size of 25 to 150 Å.

[0018] According to one embodiment, the alumina carrier may have an absorption rate of 20 to 50% with respect to the catalyst slurry.

[0019] According to one embodiment, the alumina carrier is 0.5 to 200 m 2 It can have a specific surface area of ​​ / g.

[0020] According to one embodiment, the alumina carrier is manufactured by extruding the dough, drying, and calcining, wherein the calcination temperature may be 1,000 to 1,500°C.

[0021] According to one embodiment, the organic binder may include methylcellulose as a binder, and may further include any one of polyethylene glycol, triethylene glycol, ethylene glycol, and oil as a plasticizer or lubricant among the extrusion aids, and polyvinyl alcohol as a drying regulator among the extrusion aids.

[0022] According to one embodiment, the pore-forming agent comprises one of graphite, cellulose fiber, and walnut, the liquid strength reinforcing agent is one of alumina sol, silica sol, and sodium silicate, and the solid strength reinforcing agent may be one of calcium oxide, magnesium oxide, silica oxide, and titanium oxide.

[0023] According to one embodiment, the shape of the alumina carrier may be a bead type, a pellet type, a plate type, a monolith type, or a honeycomb type.

[0024] According to one embodiment, the catalyst slurry may comprise 25 to 40 parts by weight of a metal oxide, 15 to 30 parts by weight of the catalyst active component, and 0.5 to 15 parts by weight of a co-catalyst.

[0025] According to one embodiment, the catalytic active component may contain one or more selected from the group consisting of ruthenium (Ru), nickel (Ni), cobalt (Co), iron (Fe), rhodium (Rh), and iridium (Ir).

[0026] According to one embodiment, the co-catalyst may contain one or more selected from the group consisting of sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), rubidium (Rb), strontium (Sr), cesium (Cs), and barium (Ba).

[0027] In addition, the present invention provides an ammonia decomposition catalyst produced by the above-described manufacturing method. Effects of the invention

[0028] The ammonia decomposition catalyst comprising a porous alumina carrier for catalyst coating according to the present invention has excellent strength and catalyst coating properties, can achieve performance equivalent to or better than that of conventional catalysts even with a small amount of catalytic active material, and can have a very high level of compressive strength. Brief explanation of the drawing

[0029] FIG. 1 is a step-by-step flowchart of a method for manufacturing an ammonia decomposition catalyst according to one embodiment of the present invention. Figure 2 is a photograph showing an ammonia decomposition catalyst prepared according to one embodiment of the present invention. Figure 3 is a graph showing the ammonia decomposition performance of an ammonia decomposition catalyst according to one embodiment of the present invention. Figure 4 is a graph showing the compressive strength of an ammonia decomposition catalyst according to one embodiment of the present invention. Specific details for implementing the invention

[0030] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols will be assigned the same reference number, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not inherently possess distinct meanings or roles. Furthermore, in describing embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate easy understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings and should be understood to include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the present invention.

[0031] When it is stated that one component is "connected" or "connected" to another component, it should be understood that while it may be directly connected or connected to that other component, there may also be other components in between. On the other hand, when it is stated that one component is "directly connected" or "directly connected" to another component, it should be understood that there are no other components in between.

[0032] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0033] In this specification, terms such as “comprising” or “having” are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0035] FIG. 1 is a step-by-step flowchart of a method for manufacturing an ammonia decomposition catalyst according to one embodiment of the present invention.

[0036] As illustrated in FIG. 1, an ammonia decomposition catalyst according to one embodiment of the present invention may include the step of manufacturing a porous alumina carrier (S10) and the step of coating a catalyst slurry on the alumina carrier (S20).

[0037] Here, the step (S10) of manufacturing an alumina carrier may involve extruding a dough prepared by mixing 20 to 80 parts by weight of alumina, 5 to 40 parts by weight of an organic binder, 2 to 15 parts by weight of an inorganic binder, and 10 to 20 parts by weight of a pore-forming agent with water. Specifically, the dough may be manufactured by using an extrusion molding device to produce an extruded body, followed by drying and firing. An extrusion molding device refers to a device that extrudes the dough using an extruder such as a piston or a screw, and the present invention is not particularly limited thereto.

[0038] Alumina (Al2O3) may be any one of alpha (α-Al2O3), gamma (γ-Al2O3), theta (θ-Al2O3), and boehmite, but preferably it is alpha alumina having high heat resistance and durability. In the dough for extrusion molding, the alumina may be 20 to 80 parts by weight, more preferably 40 to 70 parts by weight, and most preferably 70 parts by weight. This alumina may have a particle size of 0.5 to 6 μm in powder form.

[0039] At this time, an organic binder as an extrusion aid and an inorganic binder as a sintering aid are mixed with water to form a paste, and then the paste is fed into the extrusion molding device to produce extruded bodies of various shapes. An extruded body according to one embodiment of the present invention can be extruded into various shapes, such as a bead type, a pellet type such as a column shape or a column shape with a hollow part, a plate type with a thin and wide shape, a monolith type with a polygonal column shape, or a honeycomb type with a hexagonal honeycomb structure.

[0040] Although alumina, particularly alpha-alumina, has high heat resistance and durability, its low specific surface area makes it difficult to apply high-content coatings, which poses significant limitations to the loading of active materials. Therefore, in addition to organic and inorganic binders, a pore-forming agent may be added to the alumina to form additional pores to improve catalyst coating properties.

[0041] At this time, the pore-forming agent is preferably a polymer such as cellulose fiber, polystyrene, polyurethane, or polypropylene, or graphite or walnut, so that it can be removed by heat during firing. However, in order for the alumina carrier to maintain a strength greater than or equal to a predetermined strength, it is preferable to add 10 to 20 parts by weight, most preferably 20 parts by weight, of the pore-forming agent. If the pore-forming agent is less than 10 parts by weight, the compressive strength is high but the porosity and water absorption rate are low, and if the pore-forming agent is more than 20 parts by weight, there is a problem of breakage or low compressive strength depending on the firing temperature.

[0042] Specifically, as shown in the table below, the alumina content and binder content were kept the same, and the porosity, water absorption rate, and compressive strength according to the content of the pore-forming agent were as shown in Table 1 below. When the pore-forming agent exceeded 20 parts by weight, it broke at 1,400°C, and when the pore-forming agent was not added, the compressive strength was high but the porosity did not reach 40%, and the water absorption rate for the catalyst slurry also did not reach 20%.

[0043] division No. 1 No. 2 No. 3 No. 4 Pore-forming agent content 0 10 parts by weight 20 parts by weight 30 parts by weight 1,400℃ firing result Good Good Good break Porosity (%) 33 % 44 % 55 % - Absorption rate (%) 13 % 22 % 32 % - Compressive strength (Mpa) 98 80 60 -

[0044] When the calcination temperature was set to 1300℃ under the same conditions, the porosity, water absorption, and compressive strength according to the content of the pore-forming agent were as shown in Table 2 below. It can be seen that compared to when the calcination temperature was 1400℃, the porosity and water absorption were slightly improved, but the compressive strength was relatively lower. Therefore, as described below, the calcination temperature when manufacturing an alumina carrier is most preferably 1400℃.

[0045] division No. 1 No. 2 No. 3 No. 4 Pore-forming agent content 0 10 parts by weight 20 parts by weight 30 parts by weight 1300℃ firing result Good Good Good break Porosity (%) 34 % 50 % 58 % - Absorption rate (%) 15 % 26 % 36 % - Compressive strength (Mpa) 47 29 18 -

[0047] In addition, the above organic binder is methylcellulose (C6H) used as a binder. 10 O5), polyethylene glycol ((C2H4O)n) used as a plasticizer or lubricant as an extrusion aid, triethylene glycol (C6H 14 It may be any one selected from O4), ethylene glycol (C2H6O2) or oil (e.g., paraffin oil, mineral oil, silicone oil, etc.), and polyvinyl alcohol ((C2H4O)n(C2H3O)n) used as a drying regulator as an extrusion aid.

[0048] In the dough for compression molding, the organic binder may be 5 to 40 parts by weight, more preferably 5 to 20 parts by weight, and most preferably 8 parts by weight.

[0049] In addition, the above-mentioned inorganic binder may be any one selected from bentonite (Al2O3·4SiO2·H2O), boehmite (AlO(OH)), clay, kaolin, feldspar, or sodium silicate (Na2SiO3) used as a binder, alumina sol (Al2O3), silica sol (SiO2), or sodium silicate (Na2SiO3) which are liquid inorganic binders used as strength reinforcing agents, and calcium oxide (CaO), magnesium oxide (MgO), silica oxide (SiO2), or titanium oxide (TiO2) which are solid inorganic binders used as strength reinforcing agents.

[0050] In the dough for compression molding, the inorganic binder may be in an amount of 2 to 15 parts by weight, more preferably 2 to 5 parts by weight, and most preferably 2 parts by weight.

[0051] In addition, regarding the kneaded dough prepared, in addition to the powder catalyst, organic binder, and inorganic binder, a shrinkage inhibitor may be further included to reduce shrinkage during the extrusion molding of the dough and to improve the stability of the extruded body even at high temperatures of the extrusion molding device. Here, the present invention does not particularly limit the shrinkage inhibitor, but as an example, stearic acid amide (C 18 H 37 It may be any one selected from NO), ethylene vinyl acetate (C4H6O2) and amide.

[0052] Subsequently, the extruded body formed by the extrusion molding device can be dried and sintered through heat treatment at a predetermined temperature in an air atmosphere. The mechanical strength and density of the alumina carrier can be increased through the sintering process, and for this purpose, the sintering temperature may be 1,000 to 1,500°C, preferably 1,300 to 1,400°C, and most preferably 1,400°C.

[0053] The alumina carrier produced in this way may be porous with a porosity of 40 to 70%, and the pore size may be 25 to 150 Å.

[0054] These porous alumina carriers are 0.5 to 200 m 2 It can have a specific surface area of ​​ / g, and since it has an absorption rate of 20 to 50% with respect to the catalyst slurry described later, it has excellent catalyst coating properties when coating the catalyst slurry, so high catalytic performance, that is, a high ammonia conversion rate, can be achieved with a small amount of catalytic active material.

[0056] Meanwhile, a catalyst slurry containing a catalyst active component can be coated onto the alumina carrier prepared in step S10 (S20).

[0057] The catalyst slurry may comprise 25 to 40 parts by weight of a metal oxide, 15 to 30 parts by weight of a catalytic active component, and 0.5 to 15 parts by weight of a co-catalyst.

[0058] The catalytic active component may include one or more selected from the group consisting of precious metals such as ruthenium (Ru), rhodium (Rj), and iridium (Ir), as well as non-precious metals such as nickel (Ni), cobalt (Co), and iron (Fe).

[0059] The catalytic active component in the catalyst slurry may be 15 to 30 parts by weight, more preferably 17 to 25 parts by weight, and most preferably 23 parts by weight.

[0060] The metal oxide mixed together may include three or more selected from the group consisting of Al2O3, CeO2, ZrO2, La2O3, Y2O3, Fe3O4, TiO2, SiO2, MgO, and CaO. The present invention is not particularly limited thereto, but according to a preferred embodiment, the three selected types are preferably Al2O3, CeO2, and ZrO, and the mixing ratio is preferably 10:4:5 or 10:6:3, and more preferably, in addition to Al2O3, CeO2, and ZrO, La2O3 and Y2O3 may be further mixed.

[0061] In the catalyst slurry, the metal oxide may be in an amount of 25 to 40 parts by weight, more preferably 26 to 35 parts by weight, and most preferably 33 parts by weight.

[0062] In addition, the catalyst performance enhancer as a co-catalyst mixed with the above-mentioned catalyst active component may be in the form of any one of nitrate, chloride, carbonate, and hydroxide for any one of the elements Na, K, Ca, Ba, Ce, Si, La, Fe, Cs, Li, Gd, Pr, Sr, Y, Co, and Mg. The present invention is not specifically limited thereto, but as a specific example, Na may be NaNO3, NaCl, NaOH, etc.; K may be KNO3, KCl, KOH, etc.; Ca may be Ca(NO3)2, CaCl2, Ca(OH)2, etc.; Ba may be Ba(NO3)2, BaCl2, Ba(OH)2, etc.; Ce may be Ce(NO3)3, CeCl3, Ce(OH)3, etc.; Si may be Si(NO3)4, SiCl4, Si(OH)4, etc.; and Mg may be Mg(NO3)2, MgCl2, Mg(OH)2, etc.

[0063] In the catalyst slurry, the co-catalyst may be in an amount of 0.5 to 15 parts by weight, more preferably 4 to 10 parts by weight, and most preferably 4 parts by weight.

[0064] Such a catalyst slurry can be prepared by further mixing a dispersant containing one or more selected from the group consisting of Al-sol, Si-sol, and bohemite in addition to a metal oxide support, a catalyst active component, and a catalyst performance enhancer.

[0065] The catalyst slurry prepared in this way can be coated onto a porous alumina carrier prepared in step S10 in an amount of 30 to 150 g / L, and then an ammonia decomposition catalyst can be finally produced by undergoing drying and calcination steps.

[0067] Examples

[0068] 70 parts by weight of alpha alumina powder, 2 parts by weight of methylcellulose, 2 parts by weight of triethylene glycol, 2 parts by weight of oil, 2 parts by weight of plasticizer, 2 parts by weight of alumina sol, and 20 parts by weight of cellulose fiber as a pore-forming agent were mixed with water to complete the dough.

[0069] The dough thus completed was fed into an extrusion molding device to extrude a pellet-type ammonia carrier, and then the extruded pellets were dried at 105°C and baked at a temperature of 1400°C or higher for 6 hours (see Fig. 2(a)).

[0070] The porous ammonia carrier prepared in this way had a porosity of 55%, an absorption rate of 32%, and a compressive strength of 60 MPa (see Table 1).

[0071] Then, at room temperature and pressure, 30 parts by weight of granular NiNO3·6H2O, 40 parts by weight of a metal oxide containing granular Al2O3, CeO2, ZrO2, and La2O3 in a weight ratio of 10:4:5, and 5 parts by weight of granular BaNO3 were mixed with water to prepare a catalyst slurry, and then the slurry was coated and supported on the extruded body (see FIG. 2(b)).

[0072] After installing the ammonia decomposition catalyst prepared in this way into a fixed-bed reactor, ammonia gas was injected using a mass flow controller, and the temperature was controlled to 550°C and 650°C using the reactor temperature controller. The space velocity WHSV was 7500 ml / g cat·h -1 The ammonia conversion rate was calculated by performing a test and is shown in Fig. 3.

[0073] Then, the force applied to the specimen was measured by compressing the specimen vertically at a speed of 2 mm / min in a Universal Testing Machine (UTM), and the maximum force applied at the time of failure was set as the compressive strength and is shown in Fig. 4.

[0074] As shown in red in FIGS. 3 and 4, the ammonia decomposition catalyst prepared according to the present embodiment has an ammonia conversion rate of 60% or more at 550°C and 90% or more at 650°C, and 60 N / mm 2 It was found that it has a compressive strength.

[0075] In other words, it can be seen that while the performance is similar to that of the ammonia decomposition catalyst prepared according to the comparative example described below, the compressive strength is relatively very high.

[0077] Comparative example

[0078] Unlike the previous example, the manufacturing method was different. First, a powder catalyst was prepared by dry mixing 30 parts by weight of granular NiNO3·6H2O, 40 parts by weight of a metal oxide containing granular Al2O3, CeO2, ZrO2, and La2O3 in a weight ratio of 10:4:5, and 5 parts by weight of granular BaNO3 at room temperature and pressure, as the same components as the mixed material of the catalyst slurry. Then, 90 parts by weight of the powder catalyst thus prepared were mixed with 10 parts by weight of bentonite, 10 parts by weight of polyvinyl alcohol, 5 parts by weight of silica sol, and 10 parts by weight of methylcellulose, and water was added to complete the dough. In this comparative example, unlike the previous example, the pore-forming agent was excluded.

[0079] The dough thus completed was fed into an extrusion molding device to extrude a pellet-type ammonia decomposition catalyst.

[0080] The ammonia conversion rate and compressive strength of the pellet-type ammonia decomposition catalyst manufactured in this way were measured in the same manner as in the previous example and are shown together in black in Figures 3 and 4.

[0081] As a result, it was found that at catalyst evaluation temperatures of 550℃ and 650℃, the ammonia conversion rate was similar to that of the previous example, but the compressive strength was only 1 / 10 of that level.

[0083] Preferred embodiments of the present invention have been described in detail above with reference to the drawings. The description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without changing the technical concept or essential features of the present invention.

[0084] Accordingly, the scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning, scope, and equivalent concepts of the claims should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A method for manufacturing an ammonia decomposition catalyst comprising: a step of preparing a paste by mixing 40 to 70 parts by weight of alpha alumina powder having a particle size of 0.5 to 6 μm, 5 to 40 parts by weight of an organic binder, 2 to 15 parts by weight of an inorganic binder, and 10 to 20 parts by weight of a pore-forming agent with water, and then extruding the paste to produce an extruded body, and then drying and calcining to produce an alumina carrier; and a step of coating the alumina carrier with a catalyst slurry containing a catalyst active component; wherein the pore-forming agent is cellulose fiber, and the alumina carrier is porous having a pore size of 25 to 150 Å, a porosity of 40 to 70%, and a specific surface area of ​​0.5 to 200 m2 / g, and has an absorption rate of 20 to 50% with respect to the catalyst slurry. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A method for manufacturing an ammonia decomposition catalyst according to claim 1, characterized in that the calcination temperature is 1,000 to 1,500℃. Claim 7 A method for manufacturing an ammonia decomposition catalyst according to claim 1, wherein the organic binder comprises methylcellulose as a binder, and further comprises one of polyethylene glycol, triethylene glycol, ethylene glycol, and oil as a plasticizer or lubricant among extrusion aids, and polyvinyl alcohol as a drying regulator among extrusion aids. Claim 8 A method for manufacturing an ammonia decomposition catalyst according to claim 1, wherein the pore-forming agent comprises one of graphite, cellulose fiber, and walnut, and the inorganic binder comprises a liquid strength reinforcing agent or a solid strength reinforcing agent, wherein the liquid strength reinforcing agent is one of alumina sol, silica sol, and sodium silicate, and the solid strength reinforcing agent is one of calcium oxide, magnesium oxide, silica oxide, and titanium oxide. Claim 9 A method for manufacturing an ammonia decomposition catalyst according to claim 1, characterized in that the shape of the alumina carrier is a bead type, pellet type, plate type, monolith type, or honeycomb type. Claim 10 A method for manufacturing an ammonia decomposition catalyst according to claim 1, wherein the catalyst slurry comprises 25 to 40 parts by weight of a metal oxide, 15 to 30 parts by weight of a catalytic active component, and 0.5 to 15 parts by weight of a co-catalyst. Claim 11 A method for manufacturing an ammonia decomposition catalyst according to claim 10, wherein the catalytic active component contains one or more selected from the group consisting of ruthenium (Ru), nickel (Ni), cobalt (Co), iron (Fe), rhodium (Rh), and iridium (Ir). Claim 12 A method for producing an ammonia decomposition catalyst according to claim 10, wherein the co-catalyst contains one or more selected from the group consisting of sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), rubidium (Rb), strontium (Sr), cesium (Cs), and barium (Ba). Claim 13 An ammonia decomposition catalyst manufactured by a manufacturing method according to any one of claims 1, 6 to 12.

Images