Catalyst for ammonia decomposition reaction, method for producing same, and method for producing hydrogen using catalyst for ammonia decomposition reaction

Abstract

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 catalyst for an ammonia decomposition reaction, and more particularly, to a method for producing a catalyst for an ammonia decomposition reaction by supporting highly active ruthenium on a lanthanum-cerium composite oxide support at low cost and with high efficiency, and a method for producing a catalyst for an ammonia decomposition reaction, whereby it is possible to easily produce a catalyst that exhibits a higher ammonia conversion rate than conventional catalysts for an ammonia decomposition reaction. A catalyst for an ammonia decomposition reaction, which is produced by the catalyst for an ammonia decomposition reaction; and a method for producing hydrogen using the catalyst for an ammonia decomposition reaction.

Description

Technical Field

[0001] The present invention relates to an ammonia decomposition reaction catalyst, a method for producing the same, and a method for producing hydrogen using the ammonia decomposition reaction catalyst, and more particularly to an ammonia decomposition reaction catalyst capable of improving an ammonia conversion rate in an ammonia decomposition reaction, a method for producing the same, and a method for producing hydrogen using the ammonia decomposition reaction catalyst. Background Art

[0002] With the recent intensification of climate change, hydrogen energy has attracted worldwide attention as an environmentally friendly alternative to fossil fuels. In order to realize the practical application of hydrogen energy, it is crucial to develop a technology that can safely and efficiently store and transport hydrogen. Although there are many methods for storing hydrogen, as a hydrogen storage medium installed in fuel cell vehicles, the method of using a hydrogen storage material that can reversibly store and release hydrogen is highly anticipated.

[0003] As one of the methods to effectively store and transport hydrogen, ammonia can be used as a hydrogen storage and supply source. Since the process of decomposing ammonia into hydrogen and nitrogen is an endothermic process, energy is consumed to obtain the product. In the existing catalytic decomposition reaction, a large amount of heat is required to obtain a useful amount of hydrogen, so a large amount of cost will be consumed in the process of producing hydrogen.

[0004] 2NH 3 →3H 2 +N 2 (Endothermic reaction) (1)

[0005] An ammonia decomposition reaction catalyst is a catalyst for decomposing ammonia into nitrogen and hydrogen. When obtaining high-purity hydrogen using ammonia decomposition catalysts that have been proposed so far, there is a problem that the conversion rate decreases.

[0006] In view of the above situation, the present invention proposes a novel ammonia decomposition catalyst having a high conversion rate from ammonia to nitrogen and hydrogen.

[0007] As a prior art, Japanese Patent Gazette No. 6381131 proposes a method of producing a magnesium compound and a ruthenium compound in an aqueous solution by precipitating the compound with an alkali metal carbonate, drying, calcining, and reducing the compound, which has a high specific surface area and in which ruthenium is uniformly supported to a point including a peak of pore diameter distribution appearing at a certain point. The ruthenium supported catalyst is near a basic magnesium carbonate support.

[0008] In addition, Korean Registered Patent Gazette No. 2303094 proposes a catalyst for decomposing ammonia in which, after a cerium carrier is produced by calcining a cerium precursor, the ruthenium precursor is loaded, dried and fired in such a manner that 1 to 10 parts by weight of ruthenium are contained in 100 parts by weight of the cerium carrier, so that ruthenium is replaced and bonded to the structure within the cerium lattice.

[0009] However, the aforementioned patents only attempt to enhance the catalytic activity of ruthenium by adding other active substances to the catalyst or deforming the carrier, rather than enhancing the catalytic activity by changing the manufacturing method of the ruthenium catalyst as in the present invention.

[0010] In addition, in the industrial use of catalysts, in order to solve the problem of pressure drop and improve its ease of use, the catalyst carrier is formed before use. However, considering the problem of active metal condensation caused by the limited specific surface area of ​​the catalyst carrier when the active metal is loaded on the carrier as described above and the material transfer resistance, a more economical method for producing a catalyst for ammonia decomposition reaction with a higher ammonia conversion rate is needed.

[0011] The present invention provides a method for producing a catalyst having a higher ammonia decomposition activity than conventional production methods by improving a method for producing a catalyst for an ammonia decomposition reaction, and a catalyst produced by the production method.

[0012] Prior art literature

[0013] Patent Literature

[0014] (Patent Document 1) Japanese Patent Publication No. 6381131 (Publication Date: 2016.09.05)

[0015] (Patent Document 2) Korean Registered Patent Gazette No. 2303094 (Publication Date: 2021.01.20) Summary of the invention

[0016] The main object of the present invention is to provide a method for producing an ammonia decomposition reaction catalyst which can easily produce an ammonia decomposition reaction catalyst having excellent catalytic activity and exhibiting a high ammonia conversion rate, and an ammonia decomposition reaction catalyst produced by the production method.

[0017] Another object of the present invention is to provide a method for producing hydrogen by efficiently producing hydrogen from ammonia using the catalyst for ammonia decomposition reaction.

[0018] In order to achieve the above-mentioned purpose, an embodiment of the present invention provides a method for producing a catalyst for an ammonia decomposition reaction, characterized in that it includes: after adding a lanthanum-cerium composite oxide carrier to an active metal precursor solution in which a ruthenium precursor serving as an active metal precursor is dissolved, an active metal loading step is performed by causing the active metal in the precursor solution to undergo an element replacement reaction with lanthanum and / or cerium in the lanthanum-cerium composite oxide carrier to load the active metal into the lanthanum-cerium composite oxide carrier.

[0019] An implementation example of the present invention is characterized in that the active metal precursor solution in the active metal loading step contains not only a ruthenium precursor but also a cesium precursor.

[0020] In addition, the present invention is characterized in that it also includes: filtering the support loaded with active metal after the active metal loading step performed by element replacement, and washing the support to remove inactive substances and physically absorbed active metal solution present in the active metal precursor of the filtered support.

[0021] The present invention is characterized in that it may further include: a step of reducing the support loaded with active metals under a reducing atmosphere after the filtering and washing; and a step of drying the support loaded with active metals obtained in the active metal loading step before the reducing step.

[0022] Another embodiment of the present invention is characterized in that cesium is previously loaded on the lanthanum-cerium composite oxide support added to the precursor solution in the ruthenium active metal loading step.

[0023] Another implementation example of the present invention is characterized in that it can also include: a step of further loading cesium after the ruthenium active metal loading step, the loading of cesium can be performed by an impregnation method, and before the loading of cesium, one or more of the steps of drying, calcining and reducing the lanthanum-cerium composite oxide support loaded with ruthenium is performed.

[0024] A preferred embodiment of the present invention is characterized in that the lanthanum-cerium composite oxide carrier includes: (i) a step of obtaining a lanthanum and cerium mixture by adding a lanthanum precursor and a cerium precursor to a solvent; (ii) a step of generating a precipitate by adding an alkaline substance to the obtained lanthanum and cerium mixture; (iii) a step of filtering and washing the generated precipitate and then drying it; (iv) a step of obtaining a lanthanum and cerium composite oxide solid solution by calcining the dried precipitate; and (v) a step of obtaining a lanthanum-cerium composite oxide carrier by forming and then calcining the obtained lanthanum and cerium composite oxide solid solution.

[0025] A preferred embodiment of the present invention is characterized in that the mole ratio of lanthanum to cerium in the lanthanum-cerium composite oxide carrier is 0.1:0.9 to 0.5:0.5.

[0026] A preferred implementation example of the present invention is characterized in that the element replacement is performed for 30 minutes to 24 hours.

[0027] A preferred implementation example of the present invention is characterized in that the reduction treatment is performed by heating to 300° C. to 800° C. in the presence of a reducing gas.

[0028] In a preferred embodiment of the present invention, the catalyst for ammonia decomposition reaction may contain 0.1 wt% to 10 wt% of ruthenium and 0.01 wt% to 10 wt% of cesium relative to the total weight of the catalyst.

[0029] The present invention also provides a catalyst for ammonia decomposition reaction, characterized in that it is produced by the catalyst production method of the present invention, and ruthenium as an active metal is supported on a lanthanum-cerium composite oxide carrier by element substitution.

[0030] Another embodiment of the present invention provides a catalyst for an ammonia decomposition reaction and a method for producing hydrogen from ammonia through an ammonia decomposition reaction in the presence of the catalyst for an ammonia decomposition reaction, characterized in that the catalyst is manufactured by the method for manufacturing the catalyst for an ammonia decomposition reaction and comprises ruthenium supported on a lanthanum-cerium composite oxide carrier.

[0031] Another preferred embodiment of the present invention is characterized in that the ammonia decomposition reaction is performed within a temperature range of 300°C to 550°C.

[0032] According to the method for producing a catalyst for ammonia decomposition reaction of the present invention, ruthenium (Ru) can be loaded on a lanthanum-cerium composite oxide carrier by element replacement, thereby producing a catalyst system having higher ammonia decomposition activity than a catalyst produced by loading ruthenium on a separate oxide by element replacement or by other metal loading methods such as wet impregnation and dip coating. In particular, it can be more effectively applied to loading ruthenium on a shaped carrier.

[0033] Furthermore, according to the method for producing a catalyst for ammonia decomposition reaction of the present invention, it is not necessary to use a separate reducing agent, so the generation of waste water can be reduced and the reduction of catalyst activity due to unnecessary compounds can be blocked from the source.

[0034] Furthermore, the catalyst for ammonia decomposition reaction produced by the above-described method can improve the ammonia conversion rate in the ammonia decomposition reaction by virtue of its high catalyst activity, thereby efficiently producing hydrogen from ammonia. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flowchart for explaining a method for producing an ammonia decomposition reaction catalyst according to one embodiment of the present invention.

[0036] Figure 2a This is a scanning transmission microscope-energy dispersive spectrometer (STEM-EDS) mapping image illustrating the atomic distribution of Ru, Ce, La, and Cs in a dried sample manufactured according to Example 1 of the present invention but before a reduction process is performed.

[0037] Figure 2b This is a scanning transmission microscope-energy dispersive spectrometer (STEM-EDS) mapping image illustrating the atomic distribution of Ru, Ce, La, and Cs in the catalyst produced according to Example 1 of the present invention.

[0038] Figure 3 This is a graph showing the results of measuring ammonia conversion rates based on the catalyst manufacturing method of the catalysts manufactured by Example 1 and Comparative Examples 1 to 5 of the present invention.

[0039] Figure 4 This is a graph showing the results of measuring ammonia conversion using a catalyst manufacturing method based on catalysts manufactured using Example 12 and Comparative Examples 8 and 9 of the present invention.

[0040] Figure 5 This is a graph showing the results of measuring the ammonia conversion of catalyst supports of catalysts produced by Example 1 and Comparative Examples 6 and 7 of the present invention.

[0041] Figure 6 This is a graph showing the measurement results of ammonia conversion rates of the catalysts produced by Examples 1 to 4 of the present invention.

[0042] Figure 7 This is a graph showing the measurement results of ammonia conversion rate based on the ammonia replacement reaction temperature of the catalysts produced by Examples 5 to 7 of the present invention.

[0043] Figure 8 This is a graph showing the measurement results of ammonia conversion rates of the catalysts produced by Examples 1 and 8 of the present invention.

[0044] Fig. 9 This is a graph showing the results of measuring the ammonia conversion rate based on the element replacement reaction time of the catalysts manufactured by Example 2, Example 7, and Example 9 to Example 11 of the present invention.

[0045] Fig.10This is a graph showing the results of measuring ammonia conversion using the cesium addition method for the catalysts produced using Examples 13 and 17 to 18 of the present invention.

[0046] Fig.11 This is a graph showing the results of measuring ammonia conversion using the cesium addition method for the catalysts produced using Examples 12 to 16 of the present invention. DETAILED DESCRIPTION

[0047] Unless otherwise defined, the meaning of all technical and scientific terms used in this specification is the same as that commonly understood by a skilled professional in the technical field to which the present invention belongs. Generally speaking, the nomenclature used in this specification is well known and commonly used in the technical field.

[0048] The "element replacement reaction" described in this specification refers to a reaction in which, when ruthenium is loaded on a lanthanum-cerium composite oxide carrier, ruthenium is loaded on the carrier by replacing the cerium and / or lanthanum elements of the lanthanum-cerium composite oxide carrier with the cerium and / or lanthanum elements due to the reduction potential difference between the ruthenium and the lanthanum and / or cerium elements on the composite oxide.

[0049] The terms such as "equipped with", "including" or "having" recorded in this specification are only used to indicate the existence of the features, values, steps, actions, constituent elements, parts or the combination described in the specification, and do not exclude in advance the possibility that other features, values, steps, actions, constituent elements, parts or the combination not mentioned exist or are added.

[0050] The present invention relates to a method for producing a catalyst for ammonia decomposition reaction, which uses ruthenium as a main active metal and a lanthanum-cerium composite oxide as a carrier.

[0051] Ruthenium is a well-known active metal substance in the ammonia decomposition reaction. The activity of the ammonia decomposition reaction varies depending on the type of carrier and the loading method. In particular, in order to load ruthenium into a shaped carrier efficiently and at low cost, it is necessary to develop an optimal loading method.

[0052] In the present invention, as a method for efficiently supporting ruthenium at low cost as described above, it was found that when ruthenium was supported on a lanthanum-cerium composite support by an element replacement method, the ammonia decomposition activity could be increased compared to the case of using individual oxide supports that are not composite supports or catalysts produced by other metal supporting methods such as wet impregnation or dip coating.

[0053] Specifically, the catalyst manufacturing method according to the present invention relates to a method of loading ruthenium as an active metal onto a lanthanum-cerium composite oxide carrier by element replacement, thereby simplifying the active metal loading process without using a separate reducing agent, and also having a highly active ammonia decomposition catalyst and its manufacturing method. In particular, it was found that it is an effective method for manufacturing a shaped catalyst, thereby completing the present invention.

[0054] According to the method for manufacturing the catalyst of the present invention, it can also include: a step of reducing the support loaded with the active metal under a reducing atmosphere after the active metal loading step such as ruthenium, and a step of drying the support loaded with the active metal obtained in the active metal loading step before the reduction step.

[0055] In one embodiment of the present invention, as the active metal, in addition to ruthenium, cesium may be additionally used as a promoter.

[0056] The core of the present invention lies in the step of loading ruthenium onto a carrier comprising a lanthanum-cerium composite oxide by element replacement. When the step is included, the catalyst produced exhibits a higher ammonia decomposition efficiency compared to the case where ruthenium is loaded by other methods.

[0057] Next, a preferred exemplary embodiment of a method for producing a catalyst for an ammonia decomposition reaction according to the present invention will be described in detail with reference to the accompanying drawings.

[0058] Figure 1 FIG. 1 is a schematic process diagram of a method for producing a catalyst for ammonia decomposition reaction according to an embodiment of the present invention.

[0059] See also Figure 1 According to one embodiment of the present invention, a method for manufacturing a catalyst for an ammonia decomposition reaction may include: first obtaining an active metal precursor solution in which a ruthenium precursor serving as an active metal precursor is dissolved, and then adding a lanthanum-cerium composite oxide carrier thereto, thereby loading ruthenium into the carrier through an elemental substitution reaction with lanthanum and / or cerium of the lanthanum-cerium composite oxide carrier.

[0060] At this time, the ruthenium precursor can be one or more selected from the group consisting of organic compounds and inorganic compounds containing ruthenium ions, specifically, ruthenium chloride, hydrate, nitride, acetylacetonate and iodide, etc., preferably, RUCl 3 ·xH 2 O and [RU(NH 3 ) 6 ]Cl 3 Ruthenium chloride.

[0061] A ruthenium precursor as an active metal precursor may be added to a solvent for use in order to uniformly disperse and support it on a lanthanum-cerium composite oxide support described later.

[0062] As a solvent for adding the ruthenium precursor, any solvent that can dissolve the ruthenium precursor can be used without restriction. As an example, water, alcohols such as methanol and ethanol, and ketones such as acetone can be used, and the content of the solvent can also be any content that can dissolve the ruthenium precursor without restriction.

[0063] The element replacement reaction according to the present invention is characterized in that after a lanthanum-cerium composite oxide carrier containing lanthanum and cerium is added to an active metal precursor solution, a state in which element replacement can occur is maintained, so that the active metal in the active metal precursor solution is replaced with the element contained in the lanthanum-cerium composite oxide carrier through the element replacement reaction, thereby loading the active metal into the lanthanum-cerium composite oxide carrier.

[0064] Regarding the element replacement reaction, after the lanthanum-cerium composite oxide carrier is added to the active metal precursor solution, the active metal in the active metal precursor solution can be replaced with the lanthanum and / or cerium contained in the carrier through the active metal loading process even without using a separate reducing agent, thereby loading the active metal on the surface of the carrier.

[0065] The element replacement method is different from methods such as wet impregnation, dip coating and spraying. The element of the active metal can be replaced and loaded with the element in the carrier in elemental units by means of a rotary evaporator, an evaporator or a dryer without artificially removing the solvent under specific reaction conditions. This method is particularly suitable for loading active metals into carriers with limited surface areas such as shaped particles.

[0066] At this time, the element replacement reaction can be performed at room temperature to 90°C, preferably at 50°C to 90°C, and more preferably at 50°C to 80°C in terms of loading efficiency, and the replacement time can vary according to the specific situation, for example, it can be performed for 30 minutes to 24 hours, preferably for 1 hour to 18 hours, and more preferably for 3 hours to 15 hours. When the element replacement reaction temperature is above room temperature, the speed of the element replacement reaction can be increased, thereby shortening the element replacement time, and when water is used as a solvent, the solvent loss caused by gasification can be suppressed when the element replacement reaction is performed at a temperature of less than 90°C.

[0067] Next, the supported material in which the active metal is supported on the lanthanum-cerium composite oxide support as described above may be filtered and washed, and then dried.

[0068] The filtering, washing and drying can be fully implemented using methods and devices known in the industry. Washing is used to wash active metal precursors or inactive substances that are physically attached to the surface of the carrier without elemental substitution with lanthanum and / or cerium in the carrier. Any washing solvent that does not affect the activity can be used without restriction, and it can be mainly implemented using water or alcohol. At this time, drying can be adjusted at 80°C to 150°C, preferably between 90°C and 110°C, using a vacuum oven, hot air, constant temperature and humidity, and microwaves. The drying conditions described above should be understood as exemplary content.

[0069] The dried support can be treated under a reducing atmosphere to produce an ammonia decomposition reaction catalyst.

[0070] The treatment under the reducing atmosphere can be used without limitation to reduce the active metals such as ruthenium contained in the support, and as an example, it can be a method using reducing gases such as carbon monoxide, hydrocarbons and hydrogen, and a method adding reducing agents such as hydrazine, lithium aluminum hydride and sodium tetramethylborohydride. In addition, when using a reducing gas, the reducing gas can be diluted with other gases (such as nitrogen and carbon dioxide) before use. In the above method, it is appropriate to use a reduction treatment using hydrogen as the reducing gas.

[0071] When the reducing gas is used, the temperature may be preferably 300°C to 800°C, more preferably 400°C to 600°C, and the reduction treatment time may preferably be 0.5 hours to 5 hours, more preferably 1 hour to 3 hours. At this time, before the reducing gas is used for the reduction treatment, an inert gas such as nitrogen and carbon dioxide may be used, and a pre-baking may preferably be performed at a temperature of 200°C to 400°C for 1 hour to 7 hours.

[0072] By performing the reduction treatment as described above, the active metal compound will theoretically be converted into a metal exhibiting a zero-valent metal state, but in the case of insufficient reduction treatment, only a portion of the active metal compound will be reduced, resulting in the catalyst exhibiting low activity. However, even in the above case, since hydrogen is generated during the ammonia decomposition reaction, the above reaction is continued in order to achieve the same environment as the state when the reduction treatment is performed, so that the insufficiently reduced portion is reduced and the atoms become a zero-valent metal state, thereby making the catalyst exhibit high activity.

[0073] In the ammonia decomposition reaction catalyst, 0.1 wt% to 10 wt% of ruthenium as an active metal can be supported relative to the total weight of the ammonia decomposition reaction catalyst. In the ammonia decomposition reaction catalyst, when the ruthenium content relative to the total weight of the catalyst is within the above range, the active metal can be supported sufficiently and at low cost to ensure the activity of ruthenium, thereby further improving the activity of the ammonia decomposition reaction catalyst.

[0074] In one embodiment of the present invention, a calcination step may be included after the drying. The calcination step may be performed directly instead of the drying step and then the reduction may be performed, or the drying step may be omitted and the reduction may be performed directly.

[0075] In addition, the lanthanum-cerium composite oxide carrier can use a carrier containing a certain content of lanthanum and cerium without restriction. Therefore, the lanthanum-cerium composite oxide carrier can use a commercial product or self-made, and the manufacturing method of the lanthanum-cerium composite oxide carrier can be applied without restriction to the manufacturing method known in the industry.

[0076] As an example, the lanthanum-cerium composite oxide carrier can be manufactured by the following method, which includes: (i) a step of obtaining a lanthanum and cerium mixture by adding a lanthanum precursor and a cerium precursor to a solvent; (ii) a step of generating a precipitate by adding an alkaline substance to the obtained lanthanum and cerium mixture; (iii) a step of filtering and washing the generated precipitate and then drying it; (iv) a step of obtaining a lanthanum and cerium composite oxide solid solution by calcining the dried precipitate; and (v) a step of obtaining a lanthanum and cerium shaped catalyst carrier by forming and then calcining the obtained lanthanum and cerium composite oxide solid solution.

[0077] Specifically, first in step (i), a lanthanum precursor and a cerium precursor are added to a solvent and mixed and stirred to obtain a lanthanum and cerium precursor mixture.

[0078] The lanthanum precursor or cerium precursor can be one or more selected from the group consisting of organic compounds and inorganic compounds containing lanthanum or cerium ions. Specifically, one or more of their oxides, chlorides, hydroxides, bromides, iodides, nitrates, sulfates, carbonates, acetates, oxalates, fluorides, isopropoxides and organometallic complexes can be used.

[0079] In step (ii), a precipitate is generated by adding an alkaline substance to the mixture of lanthanum and cerium obtained in the manner as described above.

[0080] At this time, as the alkaline substance used, any component that can precipitate lanthanum and cerium can be used without limitation, and one or more selected from ammonia, sodium hydroxide, potassium hydroxide, hydrazine, sodium carbonate, etc. can be used without limitation.

[0081] Next, in step (iii), the generated precipitate is filtered and washed, and then placed in a vacuum oven or the like for drying. Then, in step (iv), the precipitate is calcined to obtain a lanthanum-cerium composite oxide solid solution.

[0082] The drying in step (iii) can be performed at 90°C to 110°C, and the calcination in step (iv) can be performed in an air atmosphere at 400°C to 700°C, preferably at a temperature of 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.

[0083] In the present invention, the calcination can be performed in various well-known furnaces such as a tube furnace, a convection furnace, and a grate furnace, and is not particularly limited.

[0084] For the shaped body, in the case of using the method of precipitating the metal using a reducing agent, it is not suitable because the particles exist alone. The method of artificially removing the solvent and loading by evaporators such as wet impregnation, spraying, and rotary evaporation concentrators and dryers has the problem of low efficiency in energy consumption, and methods such as dip coating have the problem of needing to repeat the loading process in order to load the required content. In addition, in order to control the inactive substances in the precursor, it is necessary to perform a separate additional process after the catalyst is manufactured. However, the loading of the element replacement method of ruthenium of the present invention, because the elements and the elements are exchanged by replacing each other, ruthenium can be loaded on a limited surface area even in the absence of a separate reducing agent, and the process can be simplified. Therefore, the catalyst manufacturing method according to the present invention is particularly suitable for loading active metals on a catalyst system in a shaped carrier.

[0085] In step (v), in order to obtain the shaped carrier as described above, the obtained lanthanum and cerium composite oxide solid solution can be formed by various forming methods such as injection molding, extrusion molding, vacuum forming and casting molding, and then calcined to obtain a lanthanum-cerium composite oxide carrier.

[0086] When the lanthanum and cerium composite oxide solid solution is molded, the molding may be performed after a certain amount of inorganic binder, organic binder, solvent, etc. are mixed into the lanthanum and cerium composite oxide solid solution to prepare a catalyst mixture.

[0087] The inorganic adhesive, organic adhesive and solvent can be any substance used in the industry without restriction and are not subject to special restrictions. As an example, as inorganic adhesives, silica sol, aluminum sol, titanium sol, water glass and boehmite can be used, as organic adhesives, cellulose, polyvinyl alcohol, polyethylene glycol, tylos and starch can be used, and as solvents, water, alcohols such as methanol and ethanol, and ketones such as acetone can be used.

[0088] 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 at 500°C to 550°C, for 1 hour to 10 hours, preferably 3 hours to 5 hours, in order to remove adhesives and solvents while preventing changes in the crystal structure of the catalyst carrier.

[0089] The mole ratio of lanthanum to cerium in the lanthanum-cerium composite oxide carrier produced by the method as described above is 0.1:0.9 to 0.5:0.5. When the mole ratio of lanthanum to cerium satisfies the above range, the various elements of the composite oxide of lanthanum and cerium can be dispersed with each other, thereby exhibiting the best electron transfer characteristics under the corresponding composition during the ruthenium element replacement reaction and thereby producing a catalyst with a high ruthenium loading content in the carrier and a highly active ammonia decomposition ability.

[0090] According to the method for producing an ammonia decomposition catalyst of the present invention, a co-catalyst may be further supported by adding a co-catalyst precursor.

[0091] In this case, the co-catalyst component may be cesium. The cesium can provide electrons to catalyst active materials such as ruthenium in the ammonia decomposition reaction to increase the electron density, thereby playing a role in making the dissociated and adsorbed nitrogen easily detach from the nitrogen molecule in the important step of the ammonia decomposition reaction and thereby improving the efficiency of the ammonia decomposition reaction.

[0092] When cesium is added as a promoter in addition to ruthenium as a catalytically active substance, the cesium may be loaded simultaneously with ruthenium by element replacement, or may be loaded before or after ruthenium is loaded.

[0093] The cesium may be preferably loaded by a method other than element replacement, more preferably loaded by impregnation, and more preferably loaded by impregnation after loading ruthenium. In the case where cesium is loaded by element replacement, cesium may be loaded on the carrier together with ruthenium by including a cesium precursor in addition to a ruthenium precursor as an active metal precursor in the metal precursor solution.

[0094] The solvent used to dissolve the active metal precursor at this time needs to be able to dissolve the ruthenium precursor and the cesium precursor at the same time, and water, alcohols such as methanol and ethanol, and ketones such as acetone can be used as the solvent.

[0095] As the cesium precursor, one or more selected from the group consisting of organic compounds and inorganic compounds containing cesium ions can be used, specifically, cesium chloride, hydrate, nitride, acetylacetonate and iodide, etc., preferably, CsNO 3 Cesium nitride.

[0096] The cesium can be loaded separately before / after loading ruthenium by element replacement, and preferably can be loaded after loading ruthenium. In the case of loading cesium on the lanthanum-cerium composite oxide carrier loaded with ruthenium as described above, one or more steps of drying, calcining and reducing the lanthanum-cerium composite oxide carrier loaded with ruthenium can be further performed after the ruthenium loading step, so as to load cesium after removing the solution filled in the pores of the carrier.

[0097] The cesium can be supported by a general supporting method, preferably by impregnation.

[0098] The content of the co-catalyst component, ie, cesium, can be determined in consideration of the content of the catalytically active substance, and is preferably 0.01 wt % to 10 wt %, more preferably 0.5 wt % to 5 wt %, relative to the total weight of the catalyst.

[0099] Another aspect of the present invention relates to a catalyst for an ammonia decomposition reaction and a method for producing hydrogen from ammonia using the catalyst for an ammonia decomposition reaction, characterized in that the catalyst is manufactured by the method for manufacturing the ammonia decomposition catalyst and contains ruthenium supported on a lanthanum-cerium composite oxide carrier.

[0100] The catalyst for ammonia decomposition reaction manufactured by the manufacturing method of the present invention can improve the dispersion of the active metal for ammonia decomposition and simultaneously improve the catalyst activity, thermal stability and durability by virtue of the strong interaction effect between the active metal for ammonia decomposition and the catalyst carrier metal oxide, thereby improving the ammonia conversion rate in the ammonia decomposition reaction.

[0101] Furthermore, according to the hydrogen production method of the present invention, the ammonia-containing gas can be treated using the ammonia decomposition reaction catalyst, and hydrogen can be produced by dehydrogenating the ammonia into nitrogen and hydrogen.

[0102] Next, the present invention will be described in more detail by way of specific examples. The following examples are only examples to help understand the present invention, and the scope of the present invention is not limited thereby.

[0103] <Example 1>

[0104] 1-1: Preparation of lanthanum-cerium composite oxide support

[0105] 75.7 g of cerium nitrate hydrate and 37.7 g of lanthanum nitrate hydrate were added to 1 L of distilled water and mixed and stirred to prepare a uniform aqueous solution. Then, 1 mol of ammonia water was dripped into the aqueous solution until the pH reached 11, thereby generating a precipitate. After filtering and washing the precipitate, it was placed in a vacuum oven and dried at 110°C for 12 hours. The dried precipitate was crushed and placed in a roaster, and then treated in an air atmosphere at 500°C for 3 hours to obtain a lanthanum and cerium composite oxide solid solution, namely La 0.33 Ce 0.67 O 1.84 . After mixing 1 g of an organic binder and 12 g of water into 20 g of the obtained lanthanum and cerium composite oxide solid solution, the mixture was formed into a pellet shape having a diameter of 2 mm and a length of 3 mm using an injection molding machine. The formed pellets were calcined in a calciner at 500° C. for 3 hours to obtain a lanthanum-cerium composite oxide carrier.

[0106] 1-2: Production of catalyst for ammonia decomposition reaction

[0107] After adding 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate to 15 ml of distilled water, 12 g of the lanthanum-cerium composite oxide carrier obtained in Example 1-1 was added. The additive was maintained at 80°C for 6 hours, so that ruthenium was loaded on the lanthanum-cerium composite oxide carrier by means of the element replacement reaction between ruthenium in ruthenium chloride hydrate and lanthanum and / or cerium in the lanthanum-cerium composite oxide. After filtering and washing the support, it was put into a vacuum oven and dried at 110°C for 12 hours. The dried precipitate was treated in a 100% hydrogen atmosphere at 500°C for 3 hours to produce a catalyst for ammonia decomposition reaction (Ru-Cs / La 0.33 Ce 0.67 O 1.84 ).

[0108] <Example 2>

[0109] A catalyst for ammonia decomposition reaction (Ru-Cs / La) loaded with 3.34 wt% ruthenium was prepared in the same manner as in Example 1, except that 12 g of the lanthanum-cerium composite oxide carrier obtained in Example 1-1 was added after 1.82 g of ruthenium chloride hydrate and 1.72 g of cesium nitrate hydrate were added to 25 ml of distilled water. 0.33 Ce 0.67 O 1.84 ).

[0110] <Example 3>

[0111] A catalyst for ammonia decomposition reaction (Ru-Cs / La) loaded with 0.68 wt% ruthenium was prepared in the same manner as in Example 1, except that 12 g of the lanthanum-cerium composite oxide carrier obtained in Example 1-1 was added after 0.52 g of ruthenium chloride hydrate and 0.49 g of cesium nitrate hydrate were added to 25 ml of distilled water. 0.33 Ce 0.67 O 1.84 ).

[0112] <Example 4>

[0113] An ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 1.07 wt% ruthenium was prepared in the same manner as in Example 1, except that 12 g of the lanthanum-cerium composite oxide carrier obtained in Example 1-1 was added after 1.04 g of ruthenium chloride hydrate and 0.98 g of cesium nitrate hydrate were added to 25 ml of distilled water. 0.33 Ce 0.67 O 1.84 ).

[0114] <Example 5>

[0115] An ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 1.79 wt% ruthenium was prepared in the same manner as in Example 2 except that the element replacement reaction was carried out at 25°C for 24 hours. 0.33 Ce 0.67 O 1.84 ).

[0116] <Example 6>

[0117] A catalyst for ammonia decomposition reaction (Ru-Cs / La) loaded with 3.06 wt% ruthenium was prepared in the same manner as in Example 2 except that the element replacement reaction was carried out at 50°C for 24 hours. 0.33 Ce 0.67 O 1.84 ).

[0118] <Example 7>

[0119] A catalyst for ammonia decomposition reaction (Ru-Cs / La) loaded with 3.34 wt% ruthenium was prepared in the same manner as in Example 2 except that the element replacement reaction was carried out at 80°C for 24 hours. 0.33 Ce 0.67 O 1.84 ).

[0120] <Example 8>

[0121] An ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 3.39 wt% ruthenium was prepared in the same manner as in Example 1 except that the element replacement reaction was carried out at 90°C for 6 hours. 0.33 Ce 0.67 O 1.84 ).

[0122] <Example 9>

[0123] An ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 1.92 wt% ruthenium was prepared in the same manner as in Example 2 except that the element replacement reaction was carried out at 80°C for 1 hour. 0.33 Ce 0.67 O 1.84 ).

[0124] <Example 10>

[0125] An ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 2.82 wt% ruthenium was prepared in the same manner as in Example 2 except that the element replacement reaction was carried out at 80°C for 3 hours. 0.33 Ce 0.67 O 1.84 ).

[0126] <Example 11>

[0127] An ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 3.62 wt% ruthenium was prepared in the same manner as in Example 2 except that the element replacement reaction was carried out at 80°C for 12 hours. 0.33 Ce 0.67 O 1.84 ).

[0128] <Example 12>

[0129] An ammonia decomposition reaction catalyst (Ru / La) loaded with 2.84 wt% ruthenium was prepared in the same manner as in Example 1 except that cesium was not added. 0.33 Ce 0.67 O 1.84 ).

[0130] <Example 13>

[0131] 13-1: Ruthenium loading

[0132] After 0.936 g of ruthenium chloride hydrate was added to 15 ml of distilled water, 12 g of the lanthanum-cerium composite oxide carrier obtained in Example 1-1 was added. The additive was maintained at 80° C. for 6 hours, so that ruthenium in the ruthenium chloride hydrate and lanthanum and / or cerium in the lanthanum-cerium composite oxide were supported on the lanthanum-cerium composite oxide carrier by means of element substitution reaction. After filtering and washing the support, it was put into a vacuum oven and dried at 110° C. for 12 hours.

[0133] 13-2: Support of Cerium

[0134] The cesium nitrate aqueous solution prepared by adding 0.35 g of cesium nitrate hydrate to 15 ml of distilled water and the stirred solution of the dried lanthanum-cerium composite oxide support loaded with ruthenium chloride obtained in 13-1 were rotated at 150 rpm at 50° C. and 72 mbar pressure to artificially evaporate water, thereby loading cerium ions on the catalyst surface. The mixture was then placed in a vacuum oven and dried at 110° C. for 12 hours. The dried precipitate was treated in a 100% hydrogen atmosphere at 500° C. for 3 hours to produce a catalyst for ammonia decomposition reaction (Cs / Ru / La 0.33 Ce 0.67 O 1.84 ).

[0135] <Example 14>

[0136] A catalyst for an ammonia decomposition reaction was produced in the same manner as in Example 13 except that 0.175 g of cesium nitrate hydrate was used.

[0137] <Example 15>

[0138] A catalyst for an ammonia decomposition reaction was produced in the same manner as in Example 13 except that 0.525 g of cesium nitrate hydrate was used.

[0139] <Example 16>

[0140] A catalyst for an ammonia decomposition reaction was produced in the same manner as in Example 13 except that 0.7 g of cesium nitrate hydrate was used.

[0141] <Example 17>

[0142] A catalyst for an ammonia decomposition reaction was produced in the same manner as in Example 1 except that 0.35 g of cesium nitrate hydrate was added.

[0143] <Example 18>

[0144] The catalyst for ammonia decomposition reaction (Ru / Cs / La) was prepared in the same manner as in Example 13, except that cerium was first loaded by wet impregnation and dried, and then the dried product was used to perform the element substitution reaction of ruthenium. 0.33 Ce 0.67 O 1.84 ).

[0145] <Comparative Example 1>

[0146] After 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate were added to 15 ml of distilled water, a ruthenium precursor aqueous solution was sprayed onto 12 g of the lanthanum-cerium composite oxide support obtained in Example 1-1, 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 produce a catalyst for ammonia decomposition reaction (Ru-Cs / La) loaded with 2.98 wt% of ruthenium. 0.33 Ce 0.67 O 1.84 ).

[0147] <Comparative Example 2>

[0148] After adding 12 g of the lanthanum-cerium composite oxide carrier obtained in 1-1 to the ruthenium precursor aqueous solution in which 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate were added to 15 ml of distilled water, the stirred liquid was rotated at 150 rpm at 50 ° C and 72 mbar pressure by a rotary evaporator to artificially evaporate water, thereby loading ruthenium ions on the catalyst surface and then putting it into a vacuum oven and drying it at 110 ° C for 12 hours. The dried product was treated in a 100% hydrogen atmosphere at 500 ° C for 3 hours to produce a catalyst for ammonia decomposition reaction (Ru-Cs / La 0.33 Ce 0.67 O 1.84 ).

[0149] <Comparative Example 3>

[0150] The ruthenium precursor aqueous solution in which 0.936 g of ruthenium chloride hydrate and 0.89 g of cesium nitrate hydrate were added to 15 ml of distilled water was added to 12 g of the lanthanum-cerium composite oxide carrier obtained in Example 1-1, and the metal aqueous solution was absorbed and loaded for 30 seconds, followed by drying 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 produce a catalyst for ammonia decomposition reaction (Ru-Cs / La) loaded with 2.32 wt% of ruthenium. 0.33 Ce 0.67 O 1.84 ).

[0151] <Comparative Example 4>

[0152] The process of absorbing and loading the ammonia decomposition reaction catalyst prepared in Comparative Example 3 and drying it in an oven at 103° C. for 1 hour was repeated 3 times in total, thereby preparing an ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 3.61 wt % of ruthenium. 0.33 Ce 0.67 O 1.84 ).

[0153] <Comparative Example 5>

[0154] The process of absorbing and loading the ammonia decomposition reaction catalyst prepared in Comparative Example 3 and drying it in an oven at 103° C. for 1 hour was repeated 5 times in total, thereby preparing an ammonia decomposition reaction catalyst (Ru-Cs / La) loaded with 4.65 wt % ruthenium. 0.33 Ce 0.67 O 1.84 ).

[0155] <Comparative Example 6>

[0156] The catalyst for ammonia decomposition reaction was prepared in the same manner as in Example 1, wherein only 113.2 g of lanthanum nitrate hydrate was used in place of cerium nitrate hydrate in the carrier preparation process of Example 1-1 and lanthanum nitrate hydrate was added to 1 L of distilled water, thereby producing a catalyst for ammonia decomposition reaction (Ru-Cs / La) loaded with 0.86 wt% of ruthenium. 2 O 3 ).

[0157] <Comparative Example 7>

[0158] The catalyst for ammonia decomposition was manufactured in the same manner as in Example 1, where only 113.5 g of cerium nitrate hydrate was used in the process of manufacturing the support in Example 1-1 instead of cerium nitrate hydrate and lanthanum nitrate hydrate added to 1 L of distilled water, thereby manufacturing a catalyst for ammonia decomposition (Ru-Cs / CeO 2 ) loaded with 1.55 wt% of ruthenium.

[0159] <Comparative Example 8>

[0160] A catalyst for ammonia decomposition (Ru / La 0.33 Ce 0.67 O 1.84 ) loaded with 3.05 wt% of ruthenium was manufactured in the same manner as in Comparative Example 1 except that cesium was not added.

[0161] <Comparative Example 9>

[0162] A catalyst for ammonia decomposition (Ru / La 0.33 Ce 0.67 O 1.84 ) loaded with 3.45 wt% of ruthenium was manufactured in the same manner as in Comparative Example 4 except that cesium was not added.

[0163] [Table 1]

[0164]

[0165] [Table 2]

[0166]

[0167] <Test Example 1: Catalyst Property Analysis>

[0168] Scanning transmission electron microscopy-energy dispersive spectroscopy (STEM-EDS) analysis of the catalyst manufactured in Example 1 was performed to observe the microstructure of the catalyst manufactured in the examples, and the results are shown in Figure 2.

[0169] As Figure 2a shown, it can be confirmed that on the surface of the dried catalyst before the reduction process manufactured in Example 1, ruthenium is located within the lanthanum and cerium oxide lattices by elemental substitution with lanthanum and cerium oxide and is uniformly dispersed.

[0170] In addition, as Figure 2b shown, it can be confirmed that when the catalyst manufactured in Example 1 is heat-treated by the reduction process, ruthenium protrudes to the surface to form particles and is uniformly dispersed on the catalyst surface with a size of 3 nm or less, indicating that the active metal, ruthenium, is uniformly supported on the catalyst surface by an elemental substitution reaction.

[0171] <Test Example 2: Catalytic Activity Measurement Based on Ruthenium Supporting Method>

[0172] Ammonia decomposition reactions were performed using the catalysts prepared in Example 1 and Comparative Examples 1 to 5, and the ammonia conversion rates were measured. The measurements were performed at atmospheric pressure, 3,000 ml / g cat. The ammonia decomposition capacity was measured at an ammonia space velocity of 1.33 °C / h and at 300 °C, 350 °C, 400 °C, 450 °C, 500 °C and 550 °C. The results are as follows: Figure 3 shown.

[0173] In addition, in order to compare the catalytic activity according to the ruthenium supporting method without adding cesium as a promoter, the ammonia decomposition reaction of the catalysts prepared by element replacement, spraying and dipping of Ru prepared in Example 12, Comparative Example 8 and Comparative Example 9 was performed as described above. The results are as follows: Figure 4 shown.

[0174] like Figure 3 as well as Figure 4 As shown, it can be confirmed that the catalysts of Example 1 and Example 12 in which ruthenium is supported by element substitution show better ammonia decomposition activity in the low temperature region below 450°C compared with the catalysts produced by different supporting methods.

[0175] This is presumably because loading methods such as wet impregnation, spraying, and dipping are more likely to exist in a form of agglomeration due to the high loading content compared to the element replacement according to the present invention, thereby reducing the interaction effect between the active metal and the carrier.

[0176] <Test Example 3: Measurement of Ruthenium Loading Amount and Catalytic Activity Based on Carrier>

[0177] The ammonia decomposition reaction was performed using the catalysts prepared in Example 1 and Comparative Examples 6 and 7, and the ammonia conversion rate was measured. The measurement was performed at normal pressure and 3,000 ml / g cat. The ammonia decomposition capacity was measured at an ammonia space velocity of 1.33 °C / h and at 300 °C, 350 °C, 400 °C, 450 °C, 500 °C and 550 °C. The results are as follows: Figure 5 shown.

[0178] like Figure 5 As shown, the catalyst produced in Example 1 exhibits excellent ammonia decomposition ability in all temperature ranges compared with Comparative Examples 6 and 7.

[0179] In addition, referring to Table 1, it can be confirmed that the ruthenium loading amount under the same loading conditions when using a lanthanum-cerium composite oxide as a carrier is much greater than the arithmetic average of the loading amounts of the individual lanthanum oxide carrier and the cerium oxide carrier, compared with Comparative Example 6 in which only lanthanum oxide was used as a carrier and Comparative Example 7 in which only cerium oxide was used as a carrier.

[0180] It is estimated that the result is because in the lanthanum-cerium composite oxide, there may be a separate ruthenium element substitution mechanism that is different from the ruthenium element substitution mechanism in individual lanthanum oxides and cerium oxides and can exhibit an enhancement effect, and the difference in ruthenium loading as described above may also affect the difference in ammonia decomposition ability between Example 1 and Comparative Examples 6 and 7.

[0181] <Test Example 4: Measurement of Catalyst Activity Based on Ruthenium Content>

[0182] Ammonia decomposition reactions were performed using the catalysts produced in Examples 1 to 4, and the ammonia conversion rates were measured. The measurements were performed at atmospheric pressure, 3,000 ml / g cat. The ammonia decomposition capacity was measured at an ammonia space velocity of 1.33 °C / h and at 300 °C, 350 °C, 400 °C, 450 °C, 500 °C and 550 °C. The results are as follows: Figure 6 shown.

[0183] like Figure 6 As shown, it can be confirmed that at a temperature of 450° C. or higher, as the ruthenium content increases, the ammonia decomposition ability also increases.

[0184] <Test Example 5: Catalyst Activity Measurement Based on Element Replacement Reaction Temperature>

[0185] The ammonia decomposition reaction was performed using the catalysts prepared in Example 1 and Examples 5 to 8, and the ammonia conversion rate was measured. The measurement was performed at normal pressure and 3,000 ml / g cat. The ammonia decomposition capacity was measured at an ammonia space velocity of 1.33 °C / h and at 300 °C, 350 °C, 400 °C, 450 °C, 500 °C and 550 °C. The results are as follows: Figure 7 as well as Figure 8 shown.

[0186] like Figure 7 As shown, the catalysts produced in Examples 6 to 7 exhibited excellent ammonia decomposition capabilities at temperatures above 350° C., compared with the catalyst of Example 5.

[0187] like Figure 8As shown, it can be confirmed that the catalyst produced in Example 1 is more excellent in ammonia decomposition ability than the catalyst produced in Example 8.

[0188] <Test Example 6: Residue Measurement Based on Element Replacement Reaction Temperature>

[0189] When manufacturing the catalysts of Examples 5 to 7, the filtered solution and the washed solution were collected during the filtering and washing process of the solution after the ruthenium element replacement reaction in Example 1-2 and measured using inductively coupled plasma (ICP). The results are shown in Table 3.

[0190] [Table 3]

[0191]

[0192] As shown in Table 3, with the increase of ruthenium loading temperature, the amount of ruthenium remaining in the solution decreased, but the amount of lanthanum and cerium increased. It can be confirmed that ruthenium is replaced with lanthanum and cerium by the reduction potential difference and ruthenium is loaded on the catalyst, and the replaced lanthanum and cerium are re-ionized, and with the increase of temperature, a large amount of ruthenium is loaded on the catalyst surface through element replacement reaction.

[0193] <Test Example 7: Catalyst Activity Measurement Based on Element Replacement Reaction Time>

[0194] The ammonia decomposition reaction was performed using the catalysts prepared in Examples 2, 7, 9 and 11, and the ammonia conversion rate was measured. The measurement was performed at normal pressure and 3,000 ml / g cat. The ammonia decomposition capacity was measured at an ammonia space velocity of 1.33 °C / h and at 300 °C, 350 °C, 400 °C, 450 °C, 500 °C and 550 °C. The results are as follows: Fig. 9 shown.

[0195] like Fig. 9 As shown, the catalysts manufactured in Examples 2, 7, 9 to 11 exhibited higher ammonia decomposition capabilities, especially the catalysts manufactured in Examples 2, 7 and 11 exhibited excellent ammonia decomposition capabilities in all temperature ranges.

[0196] <Test Example 8: Measurement of Catalyst Activity Based on Cesium Addition Method and Loading Amount>

[0197] The ammonia decomposition reaction was performed using the catalysts prepared in Example 1 and Examples 13 to 18, and the ammonia conversion rate was measured. The measurement was performed at normal pressure and 3,000 ml / g cat. The ammonia decomposition capacity was measured at an ammonia space velocity of 1.33 °C / h and at 300 °C, 350 °C, 400 °C, 450 °C, 500 °C and 550 °C. The results are as follows: Fig.10 as well as Fig.11 shown.

[0198] See also Fig.10 The catalyst in which Cs is loaded after Ru is loaded by elemental replacement as shown in Example 13 exhibits excellent ammonia decomposition ability compared with the catalyst in which the same amount of cesium precursor is used but both cesium and ruthenium are loaded by elemental replacement reaction (Example 17) and the catalyst in which cesium is first loaded on the carrier and then ruthenium is loaded by elemental replacement reaction (Example 18).

[0199] See also Fig.11 As the ratio of ruthenium to cerium changes, the ammonia decomposition ability also changes, and the catalyst produced in Example 13 in which cesium is loaded at a weight ratio of 2 to the carrier exhibits the best ammonia decomposition ability.

[0200] Therefore, the method according to the present invention is a method for producing a catalyst for decomposing ammonia using ruthenium as an active metal. By loading a high content of ruthenium on a unit carrier, a higher activity per unit catalyst volume can be ensured and a higher catalytic activity can be obtained. Moreover, the catalyst produced thereby exhibits a higher ammonia decomposition ability than existing catalysts, and can therefore be effectively used in the industrial field.

[0201] The present invention has been described in detail with reference to the embodiments in the above content, but it can also be implemented in different embodiments within the concept and scope of the present invention. Therefore, the scope of the present invention should be defined in the appended claims and their equivalents, and is not limited to the specific embodiments described in this specification.

Claims

1. A method for producing a catalyst for ammonia decomposition reaction, characterized in that: include: After adding a lanthanum-cerium composite oxide support to an active metal precursor solution in which a ruthenium precursor serving as an active metal precursor is dissolved, an active metal loading step is performed in which the active metal in the precursor solution is loaded onto the lanthanum-cerium composite oxide support by causing 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.

2. The method for producing a catalyst for ammonia decomposition reaction according to claim 1, characterized in that: The active metal precursor solution in the active metal loading step contains not only a ruthenium precursor but also a cesium precursor.

3. The method for producing a catalyst for ammonia decomposition reaction according to claim 1, characterized in that: Also includes: After the active metal loading step, the support loaded with the active metal is filtered and washed to remove inactive substances and physically absorbed active metal solution present in the active metal precursor of the filtered support.

4. The method for producing a catalyst for ammonia decomposition reaction according to claim 3, characterized in that: Also includes: The washed material loaded with active metal is reduced under a reducing atmosphere.

5. The method for producing a catalyst for ammonia decomposition reaction according to claim 4, characterized in that: Also includes: The step of drying the washed material loaded with active metals before reduction.

6. The method for producing a catalyst for ammonia decomposition reaction according to claim 1, characterized in that: The lanthanum-cerium composite oxide support added to the precursor solution in the active metal supporting step has cesium supported in advance.

7. The method for producing a catalyst for ammonia decomposition reaction according to claim 1, characterized in that: Also includes: A step of further supporting cesium is performed after the active metal supporting step.

8. The method for producing a catalyst for ammonia decomposition reaction according to claim 7, characterized in that: The cesium is supported by an impregnation method.

9. The method for producing a catalyst for ammonia decomposition reaction according to claim 8, characterized in that: Prior to the cesium being supported, at least one of the steps of drying, calcining and reducing the lanthanum-cerium composite oxide support supporting ruthenium is performed.

10. The method for producing a catalyst for ammonia decomposition reaction according to any one of claims 1 to 9, characterized in that: The lanthanum- and cerium-containing shaped catalyst support comprises: (i) a step of obtaining a mixture of lanthanum and cerium by adding a lanthanum precursor and a cerium precursor to a solvent; (ii) a step of generating a mixed precipitate of lanthanum and cerium in the obtained mixture of lanthanum and cerium; (iii) filtering the generated precipitate and then drying it; (iv) a step of obtaining a lanthanum and cerium composite oxide solid solution by calcining the dried precipitate; and (v) A step of obtaining a lanthanum-and-cerium-containing shaped catalyst carrier by shaping and then calcining the obtained lanthanum-and-cerium composite oxide solid solution.

11. The method for producing a catalyst for ammonia decomposition reaction according to claim 10, characterized in that: The mole ratio of lanthanum to cerium in the lanthanum-cerium composite oxide carrier is 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, characterized in that: The ammonia decomposition reaction catalyst 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, characterized in that: The ammonia decomposition reaction catalyst contains 0.01 wt% to 10 wt% of cesium based on the total weight of the catalyst.

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

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

16. The method for producing hydrogen according to claim 15, characterized in that: The ammonia decomposition reaction is performed in the range of 300°C to 550°C.

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