Ammonia decomposition catalyst, its manufacturing method and hydrogen production method using the same

Abstract

The present invention relates to an ammonia decomposition catalyst, a method for producing the same, and a hydrogen production method using the same. More specifically, the present invention relates to a method for producing an ammonia decomposition catalyst, which can easily produce a catalyst that exhibits a higher ammonia conversion rate than conventional ammonia decomposition catalysts by economically and efficiently supporting highly active ruthenium on a lanthanum-cerium composite oxide support, an ammonia decomposition catalyst produced by the production method, and a hydrogen production method using the same.

Description

[Technical Field]

[0001] The present invention relates to a catalyst for an ammonia decomposition reaction, a method for producing the same, and a method for producing hydrogen using the same, and more particularly to a catalyst for an ammonia decomposition reaction that can improve an ammonia conversion rate in an ammonia decomposition reaction, a method for producing the same, and a method for producing hydrogen using the same. [Background technology]

[0002] In recent years, as climate change has worsened, hydrogen energy has been attracting attention worldwide as an environmentally friendly fuel to be used in place of fossil fuels. To put hydrogen energy to practical use, it is important to develop technologies for safely and efficiently storing and transporting hydrogen. While there are various methods for storing hydrogen, the use of hydrogen storage materials that can reversibly store and release hydrogen is expected to be a hydrogen storage medium for use in fuel cell vehicles.

[0003] One method for efficiently storing and transporting hydrogen is to use ammonia as a hydrogen storage and supply source. The decomposition of ammonia into hydrogen and nitrogen is an endothermic process, requiring energy to produce the products. Existing catalytic decomposition reactions require a large amount of heat to produce useful amounts of hydrogen gas, making hydrogen production expensive. 2NH3 → 3H2 + N2 (endothermic reaction) ... (1)

[0004] Ammonia decomposition catalysts are catalysts that decompose ammonia into nitrogen and hydrogen. Conventionally, there has been a problem in that the conversion rate decreases when attempting to obtain high-purity hydrogen using ammonia decomposition catalysts that have been proposed so far.

[0005] In response to this situation, the present invention aims to provide a new ammonia decomposition catalyst having a high conversion rate from ammonia to nitrogen and hydrogen.

[0006] As a prior art, Japanese Patent No. 6381131 discloses a ruthenium-supported catalyst in which ruthenium is uniformly supported on a carrier containing basic magnesium carbonate, which has a high specific surface area and a peak in the pore size distribution at around 30 Å, and is produced by precipitating a magnesium compound and a ruthenium compound in an aqueous solution with an alkali metal carbonate, followed by drying, calcination, and reduction.

[0007] In addition, Korean Patent No. 2303094 discloses an ammonia decomposition catalyst in which a cerium precursor is calcined to prepare a cerium carrier, and then the ruthenium precursor is supported on the cerium carrier so that 1 to 10 parts by weight of ruthenium is contained per 100 parts by weight of the cerium carrier, followed by drying and calcination, thereby substituting and bonding ruthenium within the cerium lattice.

[0008] However, these patents aim to improve the catalytic activity of ruthenium by adding other active substances to the catalyst or by modifying the support, but do not aim to improve catalytic activity by changing the manufacturing method of the ruthenium catalyst as in the present invention.

[0009] Meanwhile, in industrial use of catalysts, catalyst supports are formed for use to address pressure drop issues and improve ease of use. Supporting active metals on such supports involves the problem of active metal agglomeration due to the limited specific surface area of ​​the catalyst support, as well as mass transfer resistance. Therefore, a more economical method for producing an ammonia decomposition catalyst that exhibits a high ammonia conversion rate is required.

[0010] The present invention provides an improved method for producing a catalyst for the ammonia decomposition reaction, and provides a method for producing a catalyst having higher ammonia decomposition activity than existing methods, and a catalyst produced by the method. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent No. 6381131 (Publication Date: September 5, 2016) [Patent Document 2] Korean Patent No. 2303094 (Publication Date: January 20, 2021) Summary of the Invention [Problem to be solved by the invention]

[0012] A main object of the present invention is to provide a method for producing an ammonia decomposition catalyst, which can easily produce an ammonia decomposition catalyst exhibiting excellent catalytic activity and a high ammonia conversion rate, and to provide an ammonia decomposition catalyst produced by the method.

[0013] Another object of the present invention is to provide a method for producing hydrogen, which can efficiently produce hydrogen from ammonia using the catalyst for ammonia decomposition reaction. [Means for solving the problem]

[0014] To achieve the above object, one embodiment of the present invention provides a method for producing a catalyst for ammonia decomposition reaction, comprising the steps of: adding a lanthanum-cerium composite oxide support to an active metal precursor solution in which a ruthenium precursor is dissolved as an active metal precursor; and then carrying out an elemental substitution reaction between the active metal in the precursor solution and the lanthanum and / or cerium in the lanthanum-cerium composite oxide support to support the active metal on the lanthanum-cerium composite oxide support.

[0015] In one embodiment of the present invention, the active metal precursor solution in the active metal supporting step may contain a cesium precursor in addition to a ruthenium precursor.

[0016] In addition, after the step of supporting the active metal by element substitution, the support on which the active metal is supported may be filtered, and a washing step may be further added to remove inactive materials present in the active metal precursor of the filtered support and physically absorbed active metal solution.

[0017] After the filtration and washing, a step of reducing the active metal-loaded support in a reducing atmosphere may be added, and the method may be characterized in that a step of drying the active metal-loaded support obtained in the active metal loading step may be added before the reduction step.

[0018] In another embodiment of the present invention, the lanthanum-cerium composite oxide support added to the precursor solution in the ruthenium active metal supporting step may be characterized in that cesium is pre-supported thereon.

[0019] In another embodiment of the present invention, a step of further supporting cesium may be included after the ruthenium active metal supporting step. The cesium supporting method may be by impregnation, and may be characterized by performing one or more of the steps of drying, calcining, and reducing the lanthanum-cerium composite oxide support on which ruthenium is supported before the cesium supporting step.

[0020] In a preferred embodiment of the present invention, the lanthanum-cerium composite oxide support can be characterized by being produced by a method including the steps of: (i) adding a lanthanum precursor and a cerium precursor to a solvent to obtain a lanthanum and cerium mixture; (ii) adding a basic substance to the obtained lanthanum and cerium mixture to form a precipitate; (iii) filtering, washing, and drying the formed precipitate; (iv) calcining the dried precipitate to obtain a lanthanum and cerium composite oxide solid solution; and (v) forming the obtained lanthanum and cerium composite oxide solid solution and calcining it to obtain a lanthanum-cerium composite oxide support.

[0021] In a preferred embodiment of the present invention, the lanthanum-cerium composite oxide support may be characterized in that the molar ratio of lanthanum to cerium is 0.1:0.9 to 0.5:0.5.

[0022] In a preferred embodiment of the present invention, the element substitution is carried out for 30 minutes to 24 hours.

[0023] In a preferred embodiment of the present invention, the reduction treatment can be characterized by being carried out by heating to 300° C. to 800° C. in the presence of a reducing gas.

[0024] In a preferred embodiment of the present invention, the ammonia decomposition reaction catalyst may contain ruthenium in an amount of 0.1% by weight to 10% by weight and cesium in an amount of 0.01% by weight to 10% by weight, based on the total weight of the catalyst.

[0025] The present invention also provides a catalyst for ammonia decomposition reaction, which is produced by the catalyst production method of the present invention and is characterized in that ruthenium is supported as an active metal on a lanthanum-cerium composite oxide support by elemental substitution.

[0026] Another embodiment of the present invention provides an ammonia decomposition catalyst prepared by the method for preparing an ammonia decomposition catalyst, the catalyst comprising ruthenium supported on a lanthanum-cerium composite oxide support; and a hydrogen production method for producing hydrogen from ammonia by an ammonia decomposition reaction in the presence of the ammonia decomposition catalyst.

[0027] In another preferred embodiment of the present invention, the ammonia decomposition reaction can be characterized by being carried out at a temperature in the range of 300°C to 550°C. [Effects of the Invention]

[0028] The method for producing an ammonia decomposition catalyst according to the present invention supports ruthenium (Ru) on a lanthanum-cerium composite oxide support by elemental substitution, thereby producing a catalyst system having higher ammonia decomposition activity than catalysts prepared by elemental substitution on individual oxides or by other metal support methods such as wet impregnation and dip coating. This method is particularly useful for supporting ruthenium on a molded support.

[0029] In addition, the method for preparing a catalyst for ammonia decomposition reaction according to the present invention has the advantages of reducing wastewater generation by not using a separate reducing agent and fundamentally preventing the reduction in catalytic activity due to unwanted compounds.

[0030] In addition, the ammonia decomposition catalyst produced by the above-described method can improve the ammonia conversion rate due to its high catalytic activity in the ammonia decomposition reaction, thereby enabling efficient production of hydrogen from ammonia. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a flowchart illustrating a method for producing a catalyst for an ammonia decomposition reaction according to an embodiment of the present invention. [Figure 2a] 1 shows a STEM-EDS mapping image showing the distribution of Ru, Ce, La, and Cs atoms in a dried sample prepared according to Example 1 of the present invention but before the reduction step. [Figure 2b] 1 shows a STEM-EDS mapping image showing the distribution of Ru, Ce, La, and Cs atoms in the catalyst prepared according to Example 1 of the present invention. [Figure 3] 1 is a graph showing the measurement results of ammonia conversion rates of catalysts prepared in Example 1 of the present invention and Comparative Examples 1 to 5 according to the catalyst preparation method. [Figure 4] 1 is a graph showing the measurement results of ammonia conversion rates of catalysts prepared in Example 12 of the present invention and Comparative Examples 8 and 9 according to the catalyst preparation methods. [Figure 5]1 is a graph showing the measurement results of ammonia conversion rates depending on catalyst supports of catalysts prepared in Example 1 of the present invention and Comparative Examples 6 and 7. [Figure 6] 1 is a graph showing the measurement results of ammonia conversion rates of catalysts prepared in Examples 1 to 4 of the present invention. [Figure 7] 1 is a graph showing the measurement results of ammonia conversion rates depending on element substitution reaction temperatures of catalysts prepared in Examples 5 to 7 of the present invention. [Figure 8] 1 is a graph showing the measurement results of ammonia conversion rates of catalysts prepared in Examples 1 and 8 of the present invention. [Figure 9] 1 is a graph showing the measurement results of ammonia conversion rate as a function of element substitution reaction time for catalysts prepared in Examples 2, 7, and 9 to 11 of the present invention. [Figure 10] 1 is a graph showing the measurement results of ammonia conversion rates according to cesium addition methods for catalysts prepared in Examples 13 and 17 to 18 of the present invention. [Figure 11] 1 is a graph showing the measurement results of ammonia conversion rates according to cesium addition methods for catalysts prepared in Examples 12 to 16 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein is well known and commonly used in the art.

[0033] The term "element substitution reaction" used in this specification refers to a reaction in which, when ruthenium is supported on a lanthanum-cerium composite oxide support, ruthenium is supported on the support by elemental substitution with cerium and / or lanthanum of the lanthanum-cerium composite oxide support due to the difference in reducing level between lanthanum and / or cerium on the composite oxide and the element.

[0034] As used herein, terms such as "comprise," "include," or "have" indicate the presence of features, values, steps, operations, components, parts, or combinations thereof described herein, but do not exclude the possibility that other features, values, steps, operations, components, parts, or combinations thereof not mentioned may be present or added.

[0035] The present invention relates to a method for producing a catalyst for the ammonia decomposition reaction, which uses ruthenium as the main active metal and a lanthanum-cerium composite oxide as the support.

[0036] Ruthenium is a well-known substance as an active metal in the ammonia decomposition reaction. However, its activity in the ammonia decomposition reaction varies depending on the type of support and the method of support. Therefore, in order to efficiently and economically support ruthenium on a shaped support, it is necessary to develop an optimal support method.

[0037] The present invention is based on the discovery that when ruthenium is supported on a lanthanum-cerium composite support by an element substitution method, which is a method that can economically and efficiently support ruthenium, ammonia decomposition activity can be increased compared to catalysts prepared using respective oxide supports rather than composite supports, or catalysts prepared using other metal support methods such as wet impregnation and dip coating.

[0038] More specifically, the catalyst manufacturing method according to the present invention relates to an ammonia decomposition catalyst and a manufacturing method thereof that has high activity while simplifying the active metal loading process by loading ruthenium, an active metal, on a lanthanum-cerium composite oxide support by elemental substitution, without using a separate reducing agent, and that is particularly effective as a manufacturing method for a molded catalyst, leading to the completion of the present invention.

[0039] In the method for producing a catalyst according to the present invention, a step of reducing the support carrying the active metal in a reducing atmosphere can be added after the step of supporting an active metal such as ruthenium, and a step of drying the support carrying the active metal obtained in the active metal supporting step can be added before the reduction step.

[0040] In one embodiment of the present invention, in addition to ruthenium as the active metal, cesium may be used as a promoter.

[0041] The key point of the present invention is the step of supporting ruthenium on a support containing lanthanum-cerium composite oxide by element substitution. When this step is included, the ammonia decomposition efficiency of the prepared catalyst is higher than when ruthenium is supported by other methods.

[0042] Hereinafter, examples will be described in detail with reference to the accompanying drawings as preferred examples of the method for producing a catalyst for ammonia decomposition reaction according to the present invention.

[0043] FIG. 1 is a schematic flow chart of a method for producing a catalyst for an ammonia decomposition reaction according to one embodiment of the present invention.

[0044] Referring to FIG. 1, a method for preparing an ammonia decomposition catalyst according to an embodiment of the present invention may include the steps of first obtaining an active metal precursor solution in which a ruthenium precursor is dissolved as an active metal precursor, and then adding a lanthanum-cerium composite oxide support thereto to perform an elemental substitution reaction between ruthenium and / or cerium in the lanthanum-cerium composite oxide support, thereby supporting ruthenium on the support.

[0045] In this case, the ruthenium precursor may be at least one selected from the group consisting of organic compounds and inorganic compounds containing ruthenium ions, specifically ruthenium chloride, hydrate, nitride, acetylacetonate, iodide, etc., and preferably ruthenium chloride such as RuCl3·xH2O or [Ru(NH3)6]Cl3.

[0046] The ruthenium precursor as the active metal precursor can be added to a solvent so that it can be uniformly dispersed and supported on the lanthanum-cerium composite oxide support described below.

[0047] The solvent to which the ruthenium precursor is added may be any solvent capable of dissolving the ruthenium precursor. For example, the solvent may be water, alcohols such as methanol and ethanol, or ketones such as acetone. The content of the solvent may also be any content capable of dissolving the ruthenium precursor.

[0048] The element substitution reaction according to the present invention may be characterized in that a lanthanum-cerium composite oxide support containing lanthanum and cerium is added to an active metal precursor solution, and then the solution is maintained so that element substitution can occur, thereby substituting the active metal of the active metal precursor solution with the elements contained in the lanthanum-cerium composite oxide support through the element substitution reaction, thereby supporting the active metal on the lanthanum-cerium composite oxide support.

[0049] In the element substitution reaction, after adding a lanthanum-cerium composite oxide support to an active metal precursor solution, the active metal in the active metal precursor solution is substituted with lanthanum and / or cerium contained in the support through the element substitution reaction in the active metal loading process without using a separate reducing agent, thereby enabling the active metal to be loaded on the surface of the support.

[0050] Unlike wet impregnation, dip coating, spraying, etc., the element substitution method does not require the artificial removal of solvents using a rotary evaporator, evaporator, or dryer, and can substitute elements of the active metal with elements in the support element by element under specific reaction conditions. Therefore, it may be a more suitable method for supporting an active metal on a support having a limited surface area, such as a molded pellet.

[0051] In this case, the element substitution reaction may be carried out at room temperature to 90°C, preferably 50°C to 90°C, and more preferably 50°C to 80°C in terms of support efficiency, and the substitution time may vary depending on the situation, but may be, for example, 30 minutes to 24 hours, preferably 1 to 18 hours, and more preferably 3 to 15 hours. When the element substitution reaction temperature is room temperature or higher, the reaction rate of the element substitution reaction is increased, and the time required for element substitution can be shortened. When water is used as a solvent, solvent loss due to vaporization can be suppressed when the element substitution reaction is carried out at a temperature below 90°C.

[0052] Thereafter, the active metal supported on the lanthanum-cerium composite oxide support can be filtered, washed, and then dried.

[0053] The filtration, washing, and drying can be carried out using methods and equipment well known in the art. Washing involves removing active metal precursors and inactive substances that are not substituted for lanthanum and / or cerium in the support but are physically attached to the surface of the support. The washing solvent used is not limited as long as it does not affect activity, but water or alcohol is typically used. Drying can be carried out at 80°C to 150°C, preferably 90°C to 110°C, using a vacuum oven, hot air, constant temperature and humidity, microwaves, or the like. These drying conditions should be understood as illustrative.

[0054] The dried support can be treated in a reducing atmosphere to produce a catalyst for the ammonia decomposition reaction.

[0055] The treatment in the reducing atmosphere is not limited as long as it can reduce the active metal, such as ruthenium, contained in the support. Examples include a method using a reducing gas such as carbon monoxide, hydrocarbon, or hydrogen; or a method adding a reducing agent such as hydrazine, lithium aluminum hydride, or tetramethylborohydride. When a reducing gas is used, the reducing gas can also be diluted with other gases (e.g., nitrogen or carbon dioxide). Among these, reduction treatment using hydrogen as the reducing gas is preferred.

[0056] When the reducing gas is used, heating can be preferably performed at a temperature of 300°C to 800°C, more preferably 400°C to 600°C, and the reduction treatment time can be preferably 0.5 hours to 5 hours, more preferably 1 hour to 3 hours. Furthermore, prior to the reduction treatment with the reducing gas, an inert gas such as nitrogen or carbon dioxide can be used, and pre-baking can also be performed preferably at a temperature of 200°C to 400°C for 1 hour to 7 hours.

[0057] When the reduction treatment described above is carried out, the active metal compound is converted into a metal exhibiting a zero-valence metal state in principle, and if the reduction treatment is insufficient, the active metal compound is only partially reduced, resulting in low catalyst activity. However, even in such cases, hydrogen is generated during the ammonia decomposition reaction, creating an environment similar to that in which the reduction treatment was carried out. By continuing this reaction, the reduction treatment of the insufficiently reduced portion progresses, resulting in a zero-valence metal state, allowing the catalyst to exhibit high activity.

[0058] The ammonia decomposition catalyst can support ruthenium as an active metal in an amount of 0.1 to 10% by weight based on the total weight of the ammonia decomposition catalyst. When the ruthenium content in the ammonia decomposition catalyst is within the above range based on the total weight of the catalyst, the active metal for activating ruthenium can be sufficiently and economically supported, thereby further improving the activity of the ammonia decomposition catalyst.

[0059] In one embodiment of the present invention, a calcination step may be added after the drying, or the calcination step may be performed immediately after the drying step, or the reduction step may be performed immediately without the drying step.

[0060] Meanwhile, the lanthanum-cerium composite oxide support can be any support containing lanthanum and cerium at a predetermined content without limitation. Therefore, the lanthanum-cerium composite oxide support can be a commercially available product or can be manufactured, and any known manufacturing method in the art can be used to manufacture the lanthanum-cerium composite oxide support without limitation.

[0061] As an example, the lanthanum-cerium composite oxide support can be produced by a method including the steps of: (i) adding a lanthanum precursor and a cerium precursor to a solvent to obtain a lanthanum and cerium mixture; (ii) adding a basic substance to the obtained lanthanum and cerium mixture to produce a precipitate; (iii) filtering, washing, and drying the produced precipitate; (iv) calcining the dried precipitate to obtain a lanthanum and cerium composite oxide solid solution; and (v) shaping the obtained lanthanum and cerium composite oxide solid solution and calcining the shaped catalyst support containing lanthanum and cerium.

[0062] In detail, first, a lanthanum precursor and a cerium precursor are added to a solvent, mixed, and stirred to obtain a precursor mixture of lanthanum and cerium [step (i)].

[0063] The lanthanum precursor or cerium precursor may be at least one selected from the group consisting of organic compounds and inorganic compounds containing lanthanum or cerium ions. Specifically, at least one of oxides, chlorides, hydroxides, bromides, iodides, nitrates, sulfates, carbonates, acetates, oxalates, fluorides, isopropoxides, and organometallic complexes thereof may be used.

[0064] A basic substance is added to the mixture of lanthanum and cerium thus obtained to form a precipitate [step (ii)].

[0065] In this case, the basic substance used may be any component capable of precipitating lanthanum and cerium, and may be at least one selected from, but not limited to, ammonia, sodium hydroxide, potassium hydroxide, hydrazine, sodium carbonate, etc.

[0066] The resulting precipitate is then filtered, washed, and dried in a vacuum oven or the like [step (iii)], and calcined to obtain a lanthanum-cerium composite oxide solid solution [step (iv)].

[0067] The drying in step (iii) can be carried out at 90°C to 110°C, and the firing in step (iv) can be carried out in an air atmosphere at a temperature of 400°C to 700°C, preferably 500°C to 550°C, for 1 hour to 10 hours, preferably 3 hours to 5 hours, in order to obtain a lanthanum-cerium composite oxide solid solution.

[0068] The firing in the present invention can be carried out in various known furnaces such as a tube furnace, a convection furnace, a grate furnace, etc., and is not particularly limited.

[0069] In the case of a molded body, the method of precipitating a metal using a reducing agent is undesirable due to the presence of separate particles. Methods of supporting a molded body by manually removing the solvent using evaporators and dryers, such as wet impregnation, spraying, or rotary evaporators, are inefficient in terms of energy consumption. Furthermore, methods such as dip coating require repeated support steps to achieve the desired loading. Furthermore, additional steps are required after catalyst preparation to control inactive materials in the precursor. However, the ruthenium element substitution method of the present invention allows ruthenium to be supported on a limited surface area without the need for a separate reducing agent, thereby simplifying the process. Therefore, the catalyst preparation method of the present invention is particularly preferred for catalyst systems in which an active metal is supported on a molded support.

[0070] To obtain such a formed support, the obtained lanthanum and cerium composite oxide solid solution can be formed by various forming methods such as injection molding, extrusion molding, vacuum forming, casting molding, etc., and then calcined to obtain a lanthanum-cerium composite oxide support [step (v)].

[0071] When forming the lanthanum and cerium composite oxide solid solution, an inorganic binder, an organic binder, a solvent, etc. may be mixed with the lanthanum and cerium composite oxide solid solution in predetermined amounts to prepare a catalyst mixture, which may then be formed.

[0072] The inorganic binder, organic binder, and solvent are not particularly limited and may be any binder commonly used in the art. For example, the inorganic binder may be silica sol, alumina sol, titania sol, water glass, boehmite, etc., the organic binder may be cellulose, polyvinyl alcohol, polyethylene glycol, tylose, starch, etc., and the solvent may be water, alcohols such as methanol and ethanol, ketones such as acetone, etc.

[0073] The calcination in step (v) can be carried out in an oxidizing, reducing, or inert atmosphere at a temperature of 400°C to 700°C, preferably 500°C to 550°C, for 1 hour to 10 hours, preferably 3 hours to 5 hours, in order to remove binders, solvents, etc. while preventing changes in the crystal structure of the catalyst support.

[0074] The lanthanum-cerium composite oxide support thus prepared has a lanthanum to cerium molar ratio of 0.1:0.9 to 0.5:0.5. When the lanthanum to cerium molar ratio satisfies the above range, the elements of the lanthanum and cerium composite oxides are dispersed with each other to form a composite oxide. As a result, this composition exhibits the best electron transfer characteristics during the ruthenium element substitution reaction, and thus a catalyst having a high ruthenium content on the support and a highly active ammonia decomposition ability can be prepared.

[0075] In the method for producing the ammonia decomposition catalyst according to the present invention, a promoter precursor can be added to further support the promoter.

[0076] In this case, the promoter component may be cesium. The cesium increases electron density by donating electrons to catalytically active materials such as ruthenium in the ammonia decomposition reaction, thereby increasing the efficiency of the ammonia decomposition reaction by releasing dissociatively adsorbed nitrogen as nitrogen molecules, which is an important step in the ammonia decomposition reaction.

[0077] When cesium is added as a promoter in addition to ruthenium as a catalytically active substance, the cesium may be supported by element substitution simultaneously with ruthenium, or may be supported before or after supporting ruthenium.

[0078] The cesium is preferably supported by a method other than element substitution, more preferably by impregnation, and even more preferably by impregnation after supporting ruthenium. When supporting cesium by element substitution, cesium can be supported on the support together with ruthenium by including a cesium precursor in the active metal precursor solution as the active metal precursor in addition to a ruthenium precursor.

[0079] In this case, the solvent for dissolving the active metal precursor must be one that can simultaneously dissolve the ruthenium precursor and the cesium precursor, and the solvent may be the above-mentioned water, alcohols such as methanol and ethanol, ketones such as acetone, etc.

[0080] The cesium precursor may be at least one selected from the group consisting of organic compounds and inorganic compounds containing cesium ions, and specifically may be cesium chloride, hydrate, nitride, acetylacetonate, iodide, etc., and preferably may be a cesium nitride such as CsNO3.

[0081] The cesium may be loaded separately before or after the ruthenium is loaded by element substitution, and preferably after the ruthenium is loaded. When the cesium is loaded on the ruthenium-loaded lanthanum-cerium composite oxide support in this manner, the ruthenium-loaded lanthanum-cerium composite oxide support may be subjected to at least one step of drying, calcining, or reduction after the ruthenium loading step, thereby removing the solution that has filled the pores of the support and then loading the cesium.

[0082] The cesium may be supported by a conventional supporting method, preferably by impregnation.

[0083] The content of the promoter component cesium can be determined taking into consideration the content of catalytically active substances, and can be used preferably in an amount of 0.01 to 10% by weight, more preferably 0.5 to 5% by weight, based on the total weight of the catalyst.

[0084] From another aspect, the present invention relates to an ammonia decomposition catalyst, which is produced by the above-mentioned method for producing an ammonia decomposition catalyst and contains ruthenium supported on a lanthanum-cerium composite oxide support, and a hydrogen production method for producing hydrogen from ammonia using the ammonia decomposition catalyst.

[0085] The catalyst for ammonia decomposition reaction prepared by the method of the present invention has a high degree of dispersion of the active metal for ammonia decomposition, and a strong interaction between the active metal for ammonia decomposition and the catalyst support metal oxide, which improves all of the catalytic activity, thermal stability, and durability, thereby enabling an improvement in ammonia conversion rate in the ammonia decomposition reaction.

[0086] In addition, the method for producing hydrogen according to the present invention can produce hydrogen by treating an ammonia-containing gas using the above-mentioned catalyst for ammonia decomposition reaction and decomposing the ammonia into nitrogen and hydrogen through dehydrogenation. [Example]

[0087] The present invention will be described in more detail with reference to the following specific examples. The following examples are merely illustrative examples to aid in understanding the present invention, and the scope of the present invention is not limited thereto.

[0088] <Example 1> 1-1: Preparation of lanthanum-cerium composite oxide support 75.7 g of cerium nitrate hydrate and 37.7 g of lanthanum nitrate hydrate were added to 1 L of distilled water, mixed, and stirred to prepare a uniform aqueous solution. 1 M of ammonia water was added dropwise to this solution until the pH reached 11, producing a precipitate. The precipitate was filtered and washed, then placed in a vacuum oven and dried at 110 °C for 12 hours. The dried precipitate was crushed and placed in a calciner and treated in an air atmosphere at 500 °C for 3 hours to produce a lanthanum and cerium composite oxide solid solution, La 0.33 Ce 0.67 O 1.84 20 g of the obtained lanthanum and cerium composite oxide solid solution was mixed with 1 g of organic binder and 12 g of water, and then formed into pellets with a diameter of 2 mm and a length of 3 mm using an extruder. The formed pellets were calcined in a calciner at 500°C for 3 hours to obtain a lanthanum-cerium composite oxide support.

[0089] 1-2: Production of catalyst for ammonia decomposition reaction 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate were added to 15 mL of distilled water, and then 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1 was added. The additive was maintained at 80°C for 6 hours, and ruthenium from the ruthenium chloride hydrate was supported on the lanthanum-cerium composite oxide support by an element substitution reaction with lanthanum and / or cerium in the lanthanum-cerium composite oxide. The support was filtered, washed, and then placed in a vacuum oven and dried at 110°C for 12 hours. The dried precipitate was treated at 500°C for 3 hours in a 100% hydrogen atmosphere to obtain an ammonia decomposition catalyst (Ru-Cs / La) with 2.91 wt% ruthenium supported. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0090] <Example 2> An ammonia decomposition catalyst (Ru-Cs / La) supporting 3.34 wt% of ruthenium was prepared in the same manner as in Example 1, except that 1.82 g of ruthenium chloride hydrate and 1.72 g of cesium nitrate hydrate were added to 25 mL of distilled water, and then 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1 was added. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0091] Example 3 A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 0.68 wt% of ruthenium was prepared in the same manner as in Example 1, except that 0.52 g of ruthenium chloride hydrate and 0.49 g of cesium nitrate hydrate were added to 25 ml of distilled water, and then 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1 was added. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0092] Example 4 An ammonia decomposition catalyst (Ru-Cs / La) supporting 1.07 wt% of ruthenium was prepared in the same manner as in Example 1, except that 1.04 g of ruthenium chloride hydrate and 0.98 g of cesium nitrate hydrate were added to 25 ml of distilled water, and then 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1 was added. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0093] <Example 5> A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 1.79 wt% of ruthenium was prepared in the same manner as in Example 2, except that the element substitution reaction was carried out at 25°C for 24 hours. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0094] Example 6 A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 3.06 wt% of ruthenium was prepared in the same manner as in Example 2, except that the element substitution reaction was carried out at 50°C for 24 hours. 0.33 Ce0.67 O 1.84 ) was manufactured.

[0095] Example 7 A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 3.34 wt% of ruthenium was prepared in the same manner as in Example 2, except that the element substitution reaction was carried out at 80°C for 24 hours. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0096] Example 8 A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 3.39 wt% of ruthenium was prepared in the same manner as in Example 1, except that the element substitution reaction was carried out at 90°C for 6 hours. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0097] Example 9 A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 1.92 wt% of ruthenium was prepared in the same manner as in Example 2, except that the element substitution reaction was carried out at 80°C for 1 hour. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0098] Example 10 A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 2.82 wt% of ruthenium was prepared in the same manner as in Example 2, except that the element substitution reaction was carried out at 80°C for 3 hours. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0099] Example 11 A catalyst for ammonia decomposition reaction (Ru-Cs / La) supporting 3.62 wt% of ruthenium was produced in the same manner as in Example 2, except that the element substitution reaction was carried out at 80°C for 12 hours. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0100] Example 12 A catalyst for ammonia decomposition reaction (Ru / La) supporting 2.84 wt% of ruthenium was produced in the same manner as in Example 1, except that cesium was not added. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0101] Example 13 13-1: Supporting of ruthenium 0.936 g of ruthenium chloride hydrate was added to 15 mL of distilled water, followed by the addition of 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1. The mixture was maintained at 80°C for 6 hours, and ruthenium was supported on the lanthanum-cerium composite oxide support through an elemental substitution reaction between the ruthenium in the ruthenium chloride hydrate and the lanthanum and / or cerium in the lanthanum-cerium composite oxide. The support was filtered and washed, and then dried in a vacuum oven at 110°C for 12 hours.

[0102] 13-2: Cesium loading A stirred solution of an aqueous cesium nitrate solution prepared by adding 0.35 g of cesium nitrate hydrate to 15 ml of distilled water and the dried ruthenium chloride-loaded lanthanum-cerium composite oxide support obtained in 13-1 was artificially evaporated using a rotary evaporator at 50 °C, 72 mbar pressure, and 150 rpm to load cesium ions onto the catalyst surface. The catalyst was then dried in a vacuum oven at 110 °C for 12 hours. The dried precipitate was treated in a 100% hydrogen atmosphere at 500 °C for 3 hours to prepare an ammonia decomposition catalyst (CS / Ru / La). 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0103] Example 14 A catalyst for ammonia decomposition reaction was produced in the same manner as in Example 13, except that 0.175 g of cesium nitrate hydrate was used.

[0104] Example 15 A catalyst for ammonia decomposition reaction was produced in the same manner as in Example 13, except that 0.525 g of cesium nitrate hydrate was used.

[0105] Example 16 A catalyst for ammonia decomposition reaction was produced in the same manner as in Example 13, except that 0.7 g of cesium nitrate hydrate was used.

[0106] Example 17 A catalyst for the ammonia decomposition reaction was produced in the same manner as in Example 1, except that 0.35 g of cesium nitrate hydrate was added.

[0107] Example 18 The same procedure as in Example 13 was carried out to prepare an ammonia decomposition catalyst (Ru / Cs / La) except that cesium was first supported by wet impregnation and dried, and the resulting dried product was used to carry out the elemental substitution reaction of ruthenium. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0108] <Comparative Example 1> A ruthenium precursor aqueous solution prepared by adding 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate to 15 ml of distilled water was spray-coated onto 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1, and then the support was dried in a vacuum oven at 110°C for 12 hours. The dried product was treated in a 100% hydrogen atmosphere at 500°C for 3 hours to obtain an ammonia decomposition catalyst (Ru-Cs / La) with 2.98 wt% ruthenium supported. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0109] <Comparative Example 2> 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1 was added to a ruthenium precursor aqueous solution prepared by adding 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate to 15 mL of distilled water. The stirred solution was then rotated at 150 rpm at 50°C and 72 mbar pressure in a rotary evaporator to artificially evaporate the water, thereby supporting ruthenium ions on the catalyst surface. The catalyst was then dried in a vacuum oven at 110°C for 12 hours. The dried product was treated in a 100% hydrogen atmosphere at 500°C for 3 hours to obtain an ammonia decomposition catalyst (Ru-Cs / La) with 3.17 wt% ruthenium supported. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0110] <Comparative Example 3> 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1 was added to a ruthenium precursor aqueous solution prepared by adding 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate to 15 ml of distilled water. The solution was allowed to absorb and support the metal solution for 30 seconds, then dried in an oven at 103°C for 1 hour and then placed in a vacuum oven and dried at 110°C for 12 hours. The dried product was treated in a 100% hydrogen atmosphere at 500°C for 3 hours to obtain an ammonia decomposition catalyst (Ru-Cs / La) supporting 2.32 wt% ruthenium. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0111] <Comparative Example 4> The ammonia decomposition catalyst prepared in Comparative Example 3 was absorbed and loaded, and then dried in an oven at 103°C for 1 hour. This process was repeated three times to obtain an ammonia decomposition catalyst (Ru-Cs / La) loaded with 3.61 wt% ruthenium. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0112] <Comparative Example 5> The ammonia decomposition catalyst prepared in Comparative Example 3 was absorbed and supported, and then dried in an oven at 103°C for 1 hour. This process was repeated five times to obtain an ammonia decomposition catalyst (Ru-Cs / La) with 4.65 wt% ruthenium supported. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0113] <Comparative Example 6> An ammonia decomposition catalyst was produced in the same manner as in Example 1, except that in the preparation of the support in Example 1-1, 113.2 g of lanthanum nitrate hydrate alone was used instead of cerium nitrate hydrate and lanthanum nitrate hydrate, and added to 1 L of distilled water to produce an ammonia decomposition catalyst (Ru—Cs / La2O3) supporting 0.86 wt% of ruthenium.

[0114] <Comparative Example 7> An ammonia decomposition catalyst was produced in the same manner as in Example 1, except that in the preparation of the support in Example 1-1, 113.5 g of cerium nitrate hydrate alone was used instead of cerium nitrate hydrate and lanthanum nitrate hydrate, and added to 1 L of distilled water to produce an ammonia decomposition catalyst (Ru-Cs / CeO) ​​supporting 1.55 wt% of ruthenium.

[0115] <Comparative Example 8> A catalyst for ammonia decomposition reaction (Ru / La) supporting 3.05 wt% of ruthenium was prepared in the same manner as in Comparative Example 1, except that cesium was not added. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0116] <Comparative Example 9> A catalyst for ammonia decomposition reaction (Ru / La) supporting 3.45 wt% of ruthenium was prepared in the same manner as in Comparative Example 4, except that cesium was not added. 0.33 Ce 0.67 O 1.84 ) was manufactured.

[0117] [Table 1]

[0118] [Table 2]

[0119] <Experimental Example 1: Analysis of catalytic properties> In order to observe the microstructure of the catalyst prepared in the examples, STEM-EDS analysis was carried out on the catalyst prepared in Example 1, and the results are shown in FIG.

[0120] As shown in FIG. 2a, it was confirmed that ruthenium was uniformly dispersed within the lattice of lanthanum and ceria due to elemental substitution of lanthanum and ceria on the surface of the dried catalyst prepared in Example 1 before the reduction process.

[0121] Furthermore, as shown in FIG. 2b, the catalyst prepared in Example 1 was subjected to a heat treatment through a reduction process, and ruthenium was released onto the surface to form particles. The particles were 3 nm or less in size and uniformly dispersed on the surface of the catalyst, confirming that the active metal ruthenium was uniformly supported on the surface of the catalyst through an element substitution reaction.

[0122] <Experimental Example 2: Measurement of catalytic activity by ruthenium loading method> The ammonia conversion rate was measured by carrying out an ammonia decomposition reaction using the catalysts prepared in Example 1 and Comparative Examples 1 to 5. The measurement was carried out at atmospheric pressure and an ammonia space velocity of 3,000 ml / g. cat. The ammonia decomposition capacity was measured under conditions of / h and reaction temperatures of 300°C, 350°C, 400°C, 450°C, 500°C and 550°C, and the results are shown in Figure 3.

[0123] In addition, to compare the catalytic activity with that of the ruthenium-supported catalysts without the addition of cesium as a promoter, the ammonia decomposition reaction was carried out using the catalysts prepared by element substitution, spray coating, and dip coating using Ru prepared in Example 12, Comparative Example 8, and Comparative Example 9, respectively, as described above, and the results are shown in Figure 4.

[0124] As shown in FIGS. 3 and 4, the catalysts of Examples 1 and 12, in which ruthenium was supported by element substitution, exhibited superior ammonia decomposition activity at low temperatures below 450°C compared to catalysts prepared by different support methods.

[0125] This is presumably because, in the case of a loading method such as wet impregnation, spraying, or dip coating, a high content of the active metal is loaded compared to the element substitution method according to the present invention, which increases the likelihood of the active metals being present in agglomerated form, thereby reducing the effectiveness of the interaction between the active metal and the support.

[0126] <Experimental Example 3: Measurement of ruthenium loading amount and catalytic activity on support> The ammonia conversion was measured by carrying out an ammonia decomposition reaction using the catalysts prepared in Example 1 and Comparative Examples 6 and 7. The measurement was carried out at atmospheric pressure and an ammonia space velocity of 3,000 ml / g. cat. The ammonia decomposition capacity was measured under conditions of / h and reaction temperatures of 300°C, 350°C, 400°C, 450°C, 500°C and 550°C, and the results are shown in Figure 5.

[0127] As shown in FIG. 5, the catalyst prepared in Example 1 has a better ammonia decomposition ability than those prepared in Comparative Examples 6 and 7 over the entire temperature range.

[0128] Furthermore, referring to Table 1, it can be seen that the amounts of ruthenium loaded in Comparative Example 6, in which the support was made of only lanthanum oxide, and Comparative Example 7, in which the support was made of only cerium oxide, and in which the support was a lanthanum-cerium composite oxide, were much higher than the arithmetic mean values ​​of the amounts loaded in the individual lanthanum oxide and cerium oxide supports under the same loading conditions.

[0129] The above results are presumed to indicate that in the lanthanum-cerium composite oxide, there may be a separate ruthenium substitution mechanism exhibiting a synergistic effect, rather than a mechanism of ruthenium substitution by individual lanthanum oxide and cerium oxide. Such a difference in the amount of ruthenium loaded may have influenced the difference in ammonia decomposition ability between Example 1 and Comparative Examples 6 and 7.

[0130] <Experimental Example 4: Measurement of catalytic activity depending on ruthenium content> The ammonia conversion rate was measured by carrying out an ammonia decomposition reaction using each of the catalysts prepared in Examples 1 to 4. The measurement was carried out at atmospheric pressure and an ammonia space velocity of 3,000 ml / g. cat. The ammonia decomposition capacity was measured under conditions of / h and reaction temperatures of 300°C, 350°C, 400°C, 450°C, 500°C and 550°C, and the results are shown in Figure 6.

[0131] As shown in FIG. 6, it was confirmed that the ammonia decomposition ability increases as the ruthenium content increases at temperatures above 450°C.

[0132] <Experimental Example 5: Measurement of catalytic activity depending on the temperature of element substitution reaction> The ammonia conversion rate was measured by carrying out an ammonia decomposition reaction using the catalysts prepared in Examples 1 and 5 to 8. The measurement was carried out at atmospheric pressure and an ammonia space velocity of 3,000 ml / g. cat. The ammonia decomposition capacity was measured under conditions of / h and reaction temperatures of 300°C, 350°C, 400°C, 450°C, 500°C and 550°C, and the results are shown in Figures 7 and 8.

[0133] As shown in FIG. 7, the catalysts produced in Examples 6 and 7 are superior to the catalyst of Example 5 in ammonia decomposition ability at temperatures of 350° C. or higher.

[0134] As shown in FIG. 8, the catalyst prepared in Example 1 has a better ammonia decomposition ability than the catalyst prepared in Example 8.

[0135] <Experimental Example 6: Measurement of residues depending on element substitution reaction temperature> During the preparation of the catalysts of Examples 5 to 7, the filtered and washed solutions were collected during the filtration and washing processes after the ruthenium element substitution reaction of Examples 1 and 2, and the filtered and washed solutions were measured using inductively coupled plasma (ICP). The results are shown in Table 3.

[0136] [Table 3]

[0137] As shown in Table 3, as the ruthenium loading temperature increased, the amount of residual ruthenium in the solution decreased, while the amounts of lanthanum and cerium increased. This means that ruthenium is supported on the catalyst by being substituted for lanthanum and cerium due to the difference in reducing levels, and at the same time, the substituted lanthanum and cerium are re-ionized. It can be seen that as the temperature increases, a larger amount of ruthenium can be supported on the catalyst surface through the element substitution reaction.

[0138] <Experimental Example 7: Measurement of catalytic activity based on element substitution reaction time> The ammonia conversion was measured by carrying out an ammonia decomposition reaction using the catalysts prepared in Examples 2, 7, and 9 to 11. The measurement was carried out at atmospheric pressure and an ammonia space velocity of 3,000 ml / g. cat. The ammonia decomposition capacity was measured under conditions of / h and reaction temperatures of 300°C, 350°C, 400°C, 450°C, 500°C and 550°C, and the results are shown in Figure 9.

[0139] As shown in FIG. 9, the catalysts produced in Examples 2, 7, and 9 to 11 exhibited high ammonia decomposition ability, and in particular, the catalysts produced in Examples 2, 7, and 11 exhibited excellent ammonia decomposition ability over the entire temperature range.

[0140] <Experimental Example 8: Measurement of catalytic activity depending on cesium addition method and loading amount> The ammonia conversion rate was measured by carrying out an ammonia decomposition reaction using the catalysts prepared in Examples 1 and 13 to 18. The measurement was carried out at atmospheric pressure and an ammonia space velocity of 3,000 ml / g. cat. The ammonia decomposition capacity was measured under conditions of / h and reaction temperatures of 300°C, 350°C, 400°C, 450°C, 500°C and 550°C, and the results are shown in Figures 10 and 11.

[0141] Referring to FIG. 10, the catalyst in which Ru was supported by elemental substitution as in Example 13 and then Cs was supported used the same amount of cesium precursor, but showed better ammonia decomposition ability than the catalyst in which both cesium and ruthenium were supported by elemental substitution reaction (Example 17) and the catalyst in which cesium was first supported on a support and then ruthenium was supported by elemental substitution reaction (Example 18).

[0142] Referring to FIG. 11, the ammonia decomposition ability changed as the ratio of ruthenium to cesium changed, and the catalyst prepared in Example 13, in which cesium was supported at a weight ratio of 2% relative to the support, showed the best ammonia decomposition ability.

[0143] Therefore, in the method of the present invention, in the preparation of an ammonia decomposition catalyst using ruthenium as an active metal, high catalytic activity can be achieved while supporting a high content of ruthenium on a unit support so as to ensure high activity per unit catalyst volume. The catalyst thus prepared exhibits a higher ammonia decomposition ability than existing catalysts and is therefore useful in industry.

[0144] Although the present invention has been described with reference to the above embodiments, other embodiments may be constructed within the spirit and scope of the present invention. Accordingly, the scope of the present invention is defined by the appended claims and equivalents thereof, and is not limited to the specific embodiments described herein.

Claims

1. A method for producing a catalyst for ammonia decomposition reaction, comprising: A method for producing a catalyst for ammonia decomposition reaction, comprising the step of adding a lanthanum-cerium composite oxide support to an active metal precursor solution in which a ruthenium precursor is dissolved as a precursor of the active metal, and then carrying out an elemental substitution reaction between the active metal in the precursor solution and the lanthanum and / or cerium in the lanthanum-cerium composite oxide support, thereby supporting the active metal on the lanthanum-cerium composite oxide support.

2. 2. The method for preparing a catalyst for ammonia decomposition reaction according to claim 1, wherein the active metal precursor solution in the active metal supporting step contains a cesium precursor in addition to a ruthenium precursor.

3. 2. The method for producing a catalyst for ammonia decomposition reaction according to claim 1, further comprising the steps of filtering the support on which the active metal is loaded after the active metal loading step, and washing the support to remove inactive materials present in the active metal precursor of the filtered support and physically absorbed active metal solution.

4. 4. The method for producing a catalyst for ammonia decomposition reaction according to claim 3, further comprising the step of reducing the washed active metal-supported material in a reducing atmosphere.

5. 5. The method for producing a catalyst for ammonia decomposition reaction according to claim 4, further comprising the step of drying the support carrying the washed active metal before the reduction.

6. 2. The method for producing a catalyst for ammonia decomposition reaction according to claim 1, wherein the lanthanum-cerium composite oxide support added to the precursor solution in the active metal supporting step is a support on which cesium is previously supported.

7. 2. The method for producing a catalyst for ammonia decomposition reaction according to claim 1, further comprising a step of supporting cesium after the step of supporting the active metal.

8. 8. The method for producing a catalyst for ammonia decomposition reaction according to claim 7, wherein the cesium is supported by impregnation.

9. 9. The method for producing a catalyst for ammonia decomposition reaction according to claim 8, wherein the method comprises carrying out one or more of the steps of drying, calcining, and reducing the lanthanum-cerium composite oxide support on which ruthenium is supported before supporting cesium.

10. The lanthanum and cerium-containing shaped catalyst support is (i) adding a lanthanum precursor and a cerium precursor to a solvent to obtain a lanthanum and cerium mixture; (ii) forming a mixed precipitate of lanthanum and cerium with the resulting lanthanum and cerium mixture; (iii) filtering and drying the precipitate; (iv) calcining the dried precipitate to obtain a lanthanum and cerium composite oxide solid solution; (v) forming the obtained lanthanum and cerium composite oxide solid solution into a shaped catalyst support, followed by calcining the shaped catalyst support to obtain a lanthanum and cerium-containing shaped catalyst support.

11. 11. The method for producing a catalyst for ammonia decomposition reaction according to claim 10, wherein the lanthanum-cerium composite oxide support has a lanthanum to cerium molar ratio of 0.1:0.9 to 0.5:0.

5.

12. The method for producing a catalyst for ammonia decomposition reaction according to any one of claims 1 to 9, wherein the catalyst for ammonia decomposition reaction contains 0.1 wt% to 10 wt% of ruthenium based on the total weight of the catalyst.

13. The method for producing a catalyst for ammonia decomposition reaction according to any one of claims 1 to 9, wherein the catalyst for ammonia decomposition reaction contains 0.01 wt% to 10 wt% of cesium based on the total weight of the catalyst.

14. 10. A catalyst for ammonia decomposition reaction, produced by the method for producing a catalyst for ammonia decomposition reaction according to any one of claims 1 to 9, characterized in that ruthenium is supported as an active metal on a lanthanum-cerium composite oxide support by elemental substitution.

15. A method for producing hydrogen, comprising producing hydrogen from ammonia by an ammonia decomposition reaction in the presence of the catalyst for an ammonia decomposition reaction according to claim 14.

16. The method for producing hydrogen according to claim 15, wherein the ammonia decomposition reaction is carried out in the range of 300°C to 550°C.

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