Ruthenium-nickel foam composite catalyst and method for producing same

Abstract

A method for producing a catalyst for ammonia decomposition according to an embodiment of the present invention comprises the steps of: preparing an aqueous metal precursor solution and a porous support; and forming a metal-support composite by supporting a metal of the aqueous metal precursor solution on the surface of the porous support using a cyclic voltametric electrodeposition method, wherein the content of the metal may be 0.3-3.0 wt% on the basis of the total weight of the catalyst for ammonia decomposition. A catalyst for ammonia decomposition according to another embodiment of the present invention comprises: a porous support; and a metal supported on the surface of the porous support using a cyclic voltametric electrodeposition method, wherein the content of the metal may be 0.3-3.0 wt% on the basis of the total weight of the catalyst.

Description

Ruthenium-nickel foam composite catalyst and method for producing the same

[0001] The present invention relates to a ruthenium-nickel foam composite catalyst for ammonia decomposition and a method for producing the same.

[0002] Ammonia has a high weight-to-weight hydrogen storage capacity (17.6 wt.%) and a high volumetric energy density (12.8 MJ / L, 120 kg-H2 / m 3 ), and has the characteristic of easy liquefaction (approximately 10 bar at room temperature), it is attracting attention as a strong hydrogen carrier for hydrogen supply. Ammonia is composed only of hydrogen and nitrogen, making it possible to produce carbon-free hydrogen, and is being considered as the most promising carrier for overseas hydrogen imports in accordance with the basic plan for hydrogen economy implementation and hydrogen economy activation roadmap announced by the government.

[0003] Currently, active research and development is underway both domestically and internationally on hydrogen production using ammonia. The thermochemical ammonia decomposition hydrogen extraction reaction equation is NH3 → 0.5 N2 + 1.5 H2 (ΔH = 46 kJ / mol). This reaction is endothermic, making hydrogen production possible using an external heat source. Complete conversion of ammonia to hydrogen requires high-temperature reaction conditions exceeding 600°C at 1 atm and a highly active ammonia decomposition catalyst.

[0004] Therefore, efficient and economical hydrogen production requires high ammonia conversion rates, enabling the production of large quantities of hydrogen even at low hydrogen extraction temperatures below 500°C and high ammonia feed rates. This necessitates the development of highly efficient catalysts. Meanwhile, ruthenium (Ru) exhibits the highest activity when used as the active metal in ammonia decomposition catalysts. However, as this is a very expensive precious metal, a significant reduction in its use is necessary.

[0005] One aspect of the present invention is to provide a catalyst for ammonia decomposition having a low ruthenium metal content and high catalytic activity.

[0006] Another aspect of the present invention is to provide a method for easily and quickly producing an ammonia decomposition catalyst having a low ruthenium metal content and high catalytic activity.

[0007] The objectives of the present invention are not limited to the above-described scope. Those skilled in the art will have no difficulty understanding the additional objectives of the present invention from the overall content of this specification.

[0008] A method for manufacturing an ammonia decomposition catalyst according to one embodiment of the present invention comprises the steps of preparing a metal precursor aqueous solution and a porous support, respectively; and the step of forming a metal-support complex by supporting the metal of the metal precursor aqueous solution on the surface of the porous support by a cyclic voltametric electrodeposition method; wherein the metal may be included in an amount of 0.3 to 3.0 wt% based on the total weight of the ammonia decomposition catalyst.

[0009] The above porous support may be pretreated by a pretreatment step including a washing step and a drying step.

[0010] The step of drying the metal-support composite may further include a step of calcining the dried metal-support composite.

[0011] The step of preparing the above metal precursor aqueous solution may include a step of adjusting the pH to 0.1 to 2.0 by adding an acidic solution.

[0012] The above acidic solution may contain at least one selected from the group consisting of perchloric acid, nitric acid, hydrochloric acid, and sulfuric acid.

[0013] The concentration of the metal precursor contained in the above metal precursor aqueous solution may be 1 mM to 0.1 M.

[0014] The above cyclic voltage current deposition may be performed 100 to 500 times.

[0015] The above cyclic voltage current deposition may be performed in a potential range of -0.6 to 0.4 V.

[0016] The above cyclic voltage current deposition may be performed at a potential change rate of 1 mV / s to 500 mV / s.

[0017] The metal of the above metal precursor aqueous solution may be at least one metal selected from the group consisting of Ru, Pt, Ir, Pd, Ni, Al, Mg, K, Na, Rb, Cs, Ca, Sr, Ba, La, Pr, and Ce.

[0018] The above metal precursors are RuCl3, RuCl3·xH2O, RuCl3·3H2O, [Ru(NH3)6]Cl2, Ru3(CO) 12 , [Ru(CO)3Cl2]2, C 16 H 22 O2Ru, C 18 H 26 It may be at least one ruthenium metal precursor selected from the group consisting of Ru, Ru(NO)(NO3)x(OH)y (wherein x+y=3), I3Ru, Ru(C5H7O2)3, K4Ru(CN)6·xH2O, RuO2·xH2O, RuO2, KRuO4, and K2RuCl6.

[0019] The porous support may be at least one porous support selected from the group consisting of nickel foam (Ni foam), nickel mesh (Ni mesh), copper foam (Cu foam), copper mesh (Cu mesh), titanium foam (Ti foam), titanium mesh (Ti mesh), aluminum foam (Al foam), aluminum mesh (Al mesh), graphene foam (Graphene foam), graphene mesh (Graphene mesh), carbon paper (Carbon paper), carbon felt (Carbon felt), and carbon foam (Carbon foam).

[0020] The above cyclic voltammetry deposition may be performed using the porous support as the working electrode, a graphite rod as the counter electrode, and silver / silver chloride (Ag / AgCl) as the reference electrode.

[0021] According to another embodiment of the present invention, a catalyst for decomposing ammonia includes a porous support and a metal supported on the surface of the porous support by a cyclic voltametric electrodeposition method, and the metal may be included in an amount of 0.3 to 3.0 wt% based on the total weight of the catalyst.

[0022] The average particle diameter of the above metal may be 10 to 70 nm.

[0023] The above metal may be at least one metal selected from the group consisting of Ru, Pt, Ir, Pd, Ni, Al, Mg, K, Na, Rb, Cs, Ca, Sr, Ba, La, Pr and Ce.

[0024] The porous support may be at least one porous support selected from the group consisting of nickel foam (Ni foam), nickel mesh (Ni mesh), copper foam (Cu foam), copper mesh (Cu mesh), titanium foam (Ti foam), titanium mesh (Ti mesh), aluminum foam (Al foam), aluminum mesh (Al mesh), graphene foam (Graphene foam), graphene mesh (Graphene mesh), carbon paper (Carbon paper), carbon felt (Carbon felt), and carbon foam (Carbon foam).

[0025] The ammonia decomposition catalyst according to the present invention can maximize ammonia decomposition efficiency by containing a low content of ruthenium metal and exhibiting high catalytic activity. Furthermore, the method for producing an ammonia decomposition catalyst according to the present invention can easily and quickly produce an ammonia decomposition catalyst containing a low content of ruthenium metal and exhibiting high catalytic activity, thereby facilitating its commercial application.

[0026] Figure 1 illustrates a cyclic voltametric electrodeposition system for a method for manufacturing an ammonia decomposition catalyst according to one embodiment of the present invention.

[0027] Figure 2 shows SEM images of a catalyst for ammonia decomposition according to various embodiments of the present invention.

[0028] Figure 3 shows an image of a catalyst for ammonia decomposition according to various embodiments of the present invention.

[0029] FIG. 4 illustrates a thermochemical ammonia decomposition system using an ammonia decomposition catalyst according to one embodiment of the present invention and a GC-TCD system for analyzing the ammonia conversion rate.

[0030] Figure 5 is a graph showing the results of evaluating the ammonia conversion rate according to the temperature of an ammonia decomposition catalyst according to various embodiments of the present invention.

[0031] Figure 6 is a graph showing the evaluation results comparing the turnover frequency of an ammonia decomposition catalyst according to one embodiment of the present invention with that of a previously reported ammonia decomposition catalyst.

[0032] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. However, the embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0033] According to the present invention, a catalyst for ammonia decomposition having a low ruthenium metal content and high catalytic activity can be provided. Such a catalyst of the present invention can be manufactured by supporting the metal on the surface of a porous support using a cyclic voltametric electrodeposition method, so that a metal having a small average particle size is uniformly deposited.

[0034] More specifically, an ammonia decomposition catalyst according to one embodiment of the present invention comprises a porous support and a metal supported on the surface of the porous support by a cyclic voltametric electrodeposition method, and the metal may be included in an amount of 0.3 to 3.0 wt% based on the total catalyst weight, for example, 0.4 to 1.0 wt%, more specifically, 0.41 to 0.59 wt%.

[0035] The above metal is selectively deposited on the surface of the porous support by the cyclic voltammetry deposition method. If the content of the metal is less than 0.3 wt% based on the total catalyst weight, there is a problem that the catalytic activity is reduced due to the low loading amount of the active metal in the catalyst, and if it exceeds 3.0 wt%, there is a problem that excessive costs are incurred due to the unnecessary use of expensive active metal. Although the ammonia decomposition catalyst of the present invention includes a relatively low content of the active metal as described above, it can have excellent catalytic activity because the loading of the metal can be uniformly achieved by the cyclic voltammetry deposition method. Therefore, the ammonia decomposition catalyst of the present invention can be used at a low temperature of 500°C or less and a high ammonia supply rate (60 L g cat -1 h -1 ) can show high ammonia decomposition conversion efficiency even in an environment of .

[0036] The metal included in the ammonia decomposition catalyst of the present invention may be at least one selected from the group consisting of Ru, Pt, Ir, Pd, Ni, Al, Mg, K, Na, Rb, Cs, Ca, Sr, Ba, La, Pr and Ce, and preferably may be ruthenium (Ru) which exhibits high catalytic activity when used as an active metal of the ammonia decomposition catalyst.

[0037] The porous support included in the ammonia decomposition catalyst of the present invention may be at least one selected from the group consisting of nickel foam (Ni foam), nickel mesh (Ni mesh), copper foam (Cu foam), copper mesh (Cu mesh), titanium foam (Ti foam), titanium mesh (Ti mesh), aluminum foam (Al foam), aluminum mesh (Al mesh), graphene foam (Graphene foam), graphene mesh (Graphene mesh), carbon paper (Carbon paper), carbon felt (Carbon felt), and carbon foam (Carbon foam). When nickel foam (Ni Foam) is used as the porous support, nickel included in the porous support can simultaneously perform the role of an active metal of the ammonia decomposition catalyst, which is therefore efficient, and is therefore preferable.

[0038] In the ammonia decomposition catalyst of the present invention, the metal is evenly deposited on the surface of the porous support by a cyclic voltammetric deposition method, so the average particle size is small. Accordingly, the average particle size of the metal included in the ammonia decomposition catalyst of the present invention may be 10 nm to 70 nm, and preferably 10 nm to 30 nm. If the average particle size of the metal exceeds 70 nm, there is a problem that the activity of the catalyst decreases relative to the content of the active metal.

[0039] According to another embodiment of the present invention, a method for producing a catalyst for decomposing ammonia having a low content of ruthenium metal and high catalytic activity can be provided.

[0040] More specifically, a method for producing an ammonia decomposition catalyst according to one embodiment of the present invention includes the steps of respectively preparing a metal precursor aqueous solution and a porous support; and the step of supporting the metal of the metal precursor aqueous solution on the surface of the porous support by a cyclic voltametric electrodeposition method to form a metal-support complex. The metal may be included in an amount of 0.3 to 3.0 wt% based on the total weight of the ammonia decomposition catalyst, for example, 0.4 to 1.0 wt%, and more specifically, 0.41 to 0.59 wt%.

[0041] According to the method for manufacturing an ammonia decomposition catalyst of the present invention, the metal is selectively deposited on the surface of the porous support through a cyclic voltammetric deposition method, thereby minimizing the content of the active metal while manufacturing an ammonia decomposition catalyst with high catalytic activity. Therefore, the catalyst manufactured by the method for manufacturing an ammonia decomposition catalyst of the present invention can be manufactured at a low temperature of 500°C or less and at a high ammonia supply rate (60 L g cat -1 h -1 ) can exhibit high ammonia conversion efficiency even in an environment of. In addition, since the cyclic voltammetric deposition method is performed at room temperature, metal can be easily supported on the surface of a porous support, and an ammonia decomposition catalyst with uniform performance can be manufactured. Hereinafter, a method for manufacturing an ammonia decomposition catalyst according to the present invention will be described in more detail.

[0042] The metal and the porous support used in the method for producing the ammonia decomposition catalyst of the present invention may be the same as those used in the ammonia decomposition catalyst according to one embodiment of the present invention.

[0043] The step of preparing a metal precursor aqueous solution in the method for manufacturing an ammonia decomposition catalyst of the present invention includes a step of adding a metal precursor to distilled water. When ruthenium (Ru) is used as the metal, the metal precursor is RuCl3, RuCl3·xH2O, RuCl3·3H2O, [Ru(NH3)6]Cl2, Ru3(CO) 12 , [Ru(CO)3Cl2]2, C 16 H 22 O2Ru, C 18 H 26 It may be at least one selected from the group consisting of Ru, Ru(NO)(NO3)x(OH)y (wherein x+y=3), I3Ru, Ru(C5H7O2)3, K4Ru(CN)6·xH2O, RuO2·xH2O, RuO2, KRuO4 and K2RuCl6, and preferably ruthenium(III) chloride hydrate (RuCl3·xH2O). The concentration of the metal precursor in the metal precursor aqueous solution may be 0.1 mM to 1 M, for example, 1 mM to 0.1 M, and more specifically, 5 mM to 20 mM.

[0044] The step of preparing the metal precursor aqueous solution may additionally include a step of adjusting the pH of the metal precursor aqueous solution to 0.1 to 2.0 by adding at least one acidic solution selected from the group consisting of perchloric acid, nitric acid, hydrochloric acid, and sulfuric acid at a concentration of 0.01 M to 1 M. The metal precursor aqueous solution is preferably prepared under acidic conditions for ionization of the metal, and when prepared under acidic conditions of pH 0.1 to 2.0, the metal is easily ionized, so that the metal can be easily deposited on the porous support during the cyclic voltammetric deposition process.

[0045] The step of preparing a porous support in the method for manufacturing an ammonia decomposition catalyst of the present invention includes a step of pretreating the porous support by washing and drying the porous support. The step of washing the porous support includes a step of washing the porous support by immersing it in an acidic solution, for example, a hydrochloric acid solution, and then removing the acidic solution using distilled water. The step of drying the porous support from which the acidic solution has been removed may be performed at a temperature of 80°C to 120°C.

[0046] The step of forming a metal-support complex by supporting the metal of the metal precursor aqueous solution on the surface of a porous support in the method for producing an ammonia decomposition catalyst of the present invention can be performed by an electrodeposition method. When the metal-support complex is formed by the electrodeposition method, the active metal can be directly deposited on the support without producing a separate catalytic metal powder, so that a structured catalyst can be produced easily and quickly.

[0047] The step of forming the metal-support complex of the present invention can be performed, more specifically, by a cyclic voltametric electrodeposition method. During the cyclic voltametric electrodeposition process, the charge state of the porous support is repeatedly changed between positive and negative charges. Accordingly, the metal of the metal precursor aqueous solution is selectively deposited on the surface of the porous support by repeating the process of deposition and delamination. Accordingly, the active metal can be uniformly distributed on the surface of the porous support, and a highly active ammonia decomposition catalyst can be manufactured while minimizing the content of the active metal.

[0048] FIG. 1 illustrates a cyclic voltametric electrodeposition system for a method for producing an ammonia decomposition catalyst according to one embodiment of the present invention. Referring to FIG. 1, the cyclic voltametric electrodeposition can be performed by connecting a working electrode, a counter electrode, and a reference electrode immersed in a metal precursor aqueous solution to a potentiostat and circulating the voltage within a set potential range using the potentiostat. In addition, as the number of cycles of the cyclic voltametric electrodeposition increases, the metal of the metal precursor aqueous solution is uniformly deposited on the surface of the porous support. Here, the number of cycles of the cyclic voltametric electrodeposition means the number of times the set potential range is circulated during the electrodeposition process.

[0049] The porous support on which the active metal is supported is used for the working electrode. In addition, any one selected from the group consisting of a graphite rod, carbon paper, and carbon felt may be used for the counter electrode, and preferably a graphite rod may be used. In addition, any one selected from the group consisting of silver / silver chloride (Ag / AgCl), mercuric chloride (Hg2Cl2), mercury / mercuric oxide (Hg / HgO), and mercury / mercuric sulfate (Hg / HgSO4) may be used for the reference electrode, and preferably silver / silver chloride (Ag / AgCl) may be used.

[0050] The above cyclic voltammetric deposition is not particularly limited, but can be performed in a potential range of -0.6 to 0.4 V. If the potential range is narrower, the rate at which the metal is deposited on the surface of the porous support decreases, and if the potential range is wider, the structural loss of the support due to ion elution of the metal contained in the porous support may be accelerated.

[0051] The rate of change of potential in the above cyclic voltammetric deposition process is not particularly limited, but may be 1 mV / s to 500 mV / s. If the rate of change of potential is less than 1 mV / s, the rate of deposition of metal is slow, which takes an excessive amount of time, and structural loss of the support due to elution of metal ions contained in the porous support may be accelerated, and if the rate of change of potential exceeds 500 mV / s, there is a problem that metal deposition does not occur sufficiently due to excessively rapid potential change.

[0052] The number of cycles of the above cyclic voltage current deposition is not particularly limited, but may be performed 100 to 500 times. If the number of cycles of the above cyclic voltage current deposition is less than 100, there is a problem that the activity of the manufactured ammonia decomposition catalyst is reduced because the metal is not sufficiently deposited on the surface of the porous support, and if it exceeds 500 times, the amount of metal contained in the porous support that is eluted as ions becomes excessively large, causing a problem that the structural loss of the porous support itself occurs.

[0053] A method for producing an ammonia decomposition catalyst according to one embodiment of the present invention may further include a step of drying a metal-support composite; and a step of calcining the dried metal-support composite. The step of drying the metal-support composite is not particularly limited, but may be performed, for example, at a temperature of 80°C to 120°C for 11 to 13 hours. The step of calcining the dried metal-support composite is not particularly limited, but may be performed, for example, at a temperature of 400°C to 600°C for 1 to 3 hours.

[0054] Hereinafter, the present invention will be described in detail through examples. However, it should be noted that the examples described below are intended only to illustrate and concretize the present invention and are not intended to limit the scope of the invention. This is because the scope of the invention is determined by the matters set forth in the patent claims and matters reasonably inferred therefrom.

[0055] 1. Manufacture of catalyst for ammonia decomposition

[0056] Example 1

[0057] (1) Preparation of metal precursor solution

[0058] A mixture was prepared by adding ruthenium (III) chloride hydrate, a ruthenium precursor, to 60 mL of distilled water at a concentration of 10 mM and perchloric acid (HClO4) at a concentration of 0.1 M. The mixture was then stirred at room temperature (25°C) for 1 hour to prepare a ruthenium precursor solution. The pH of the ruthenium precursor solution thus obtained was 1.

[0059] (2) Pretreatment of porous support

[0060] Nickel foam was used as a porous support, washed in a 5M hydrochloric acid solution for 15 minutes, and the hydrochloric acid component was removed from the washed nickel foam using distilled water. The porous support was then pretreated by drying in an oven at 100°C for 10 hours.

[0061] (3) Metal support

[0062] The pretreated nickel foam obtained in the above (2) was connected to the working electrode, a graphite rod was connected to the counter electrode, and a silver / silver chloride (Ag / AgCl) electrode was connected to the reference electrode, respectively, and then positioned so that each electrode was immersed in the ruthenium precursor solution. Thereafter, ruthenium metal was deposited on the nickel foam support by cyclic voltammetric deposition using a potentiostat at a potential range of -0.6 V to 0.4 V and a potential change rate of 100 mV / s. At this time, the number of cycles of the cyclic voltammetric deposition was 100. Afterwards, the ruthenium-nickel foam composite loaded with ruthenium metal was dried at 100°C for 12 hours using a vacuum atmosphere oven, and the dried ruthenium-nickel foam composite was calcined at 500°C for 2 hours in an air atmosphere to manufacture a catalyst for ammonia decomposition.

[0063] Example 2

[0064] An ammonia decomposition catalyst of Example 2 was manufactured in the same manner as Example 1, except that the number of cycles of the cyclic voltage current deposition was 200.

[0065] Example 3

[0066] An ammonia decomposition catalyst of Example 3 was manufactured in the same manner as Example 1, except that the number of cycles of the cyclic voltage current deposition was 400.

[0067] Comparative Example 1

[0068] An ammonia decomposition catalyst of Comparative Example 1 was manufactured in the same manner as Example 1, except that the number of cycles of the cyclic voltage current deposition was 50.

[0069] Comparative Example 2

[0070] An ammonia decomposition catalyst of Comparative Example 2 was manufactured in the same manner as Example 1, except that the number of cycles of the cyclic voltage current deposition was 600.

[0071] 2. Confirmation of the characteristics of the catalyst for ammonia decomposition

[0072] Experimental Example 1: Quantitative analysis of metal loading using ICP-OES

[0073] The amount of Ru metal supported in the catalyst was quantitatively analyzed through ICP-OES analysis of the ammonia decomposition catalyst manufactured as described above, and the analysis results are shown in Table 1 below.

[0074] Cyclic voltage current deposition cycle number Ru content (wt%) based on total catalyst weight Example 11000.41 Example 22000.51 Example 34000.59 Comparative example 1500.23 Comparative example 26000.89

[0075] Referring to Table 1, in the case of Examples 1 to 3, it can be confirmed that the amount of Ru metal loaded increases by about 15% per 100 cycles depending on the number of cycles of the cyclic voltammetric deposition as a result of quantitative analysis of Ru metal. Therefore, it can be confirmed that the amount of Ru metal selectively deposited increases as the process of deposition and delamination on the surface of the support is repeated due to the repetitive change of positive and negative charges of the support depending on the cycle of the cyclic voltammetric deposition. On the other hand, in the case of Comparative Example 1 in which the number of cycles of the cyclic voltammetric deposition is less than 100, it can be confirmed that a very small amount of Ru metal is loaded, that is, 0.23 wt%. Accordingly, it can be confirmed that the ammonia decomposition activity evaluation below and the ammonia conversion rate shown in FIG. 4 are also significantly lower than in Examples 1 to 3. Therefore, it can be confirmed that when the number of cycles of the cyclic voltammetric deposition is less than 100, Ru metal deposition at a level suitable for use as an ammonia decomposition catalyst is not achieved.

[0076] Experimental Example 2: SEM Image Analysis

[0077] The SEM images of the ammonia decomposition catalysts manufactured as described above are shown in Fig. 2. Referring to Fig. 2, the average particle diameter of the Ru metal lumps supported in the SEM images is measured to be about 50 to 70 nm in Example 1, 30 to 60 nm in Example 2, and 10 to 30 nm in Example 3. Therefore, it can be confirmed that the average particle diameter of the Ru metal and the thickness of the Ru metal layer decrease as the number of cycles increases. This is because, during the cyclic voltammetric deposition process of the Ru metal, the deposition and removal process of the metal is repeated due to the repeated change in the positive and negative charges of the support, thereby selective deposition is achieved. Therefore, it can be judged that as the number of cycles increases, the Ru metal is deposited evenly and thinly on the support.

[0078] Meanwhile, referring to FIG. 3, in the case of comparative example 2 where the number of cycles exceeds 500, the Ni metal constituting the porous support is Ni during the cyclic voltammetry deposition process. 2+ It can be confirmed that there is a problem in that the structure of the support itself is lost due to excessive dissolution. Therefore, it can be confirmed that when the number of cycles of cyclic voltammetry exceeds 500, the structural loss of the support itself occurs, making it unsuitable for use as a catalyst for ammonia decomposition.

[0079] 3. Evaluation of ammonia decomposition activity

[0080] The ammonia decomposition conversion rates of the ammonia decomposition catalysts manufactured as described above were compared. A thermochemical ammonia decomposition hydrogen extraction reaction system, as shown in Fig. 4, was constructed to supply ammonia with a purity of 99% or higher, and the catalyst was positioned at the center of a 3 / 8-inch quartz reactor to allow the ammonia decomposition reaction to proceed. The ammonia decomposition reaction was conducted under the following conditions.

[0081] -GHSV=60,000 mL g cat -1 h-1

[0082] -Reaction temperature: 500℃

[0083] The gas generated after the above ammonia decomposition reaction was transferred to a GC-TCD and trace ammonia analyzer using a quantitative pump, and unreacted ammonia was analyzed using a gas chromatography device under the following conditions. Through this, the ammonia decomposition conversion rate was calculated, and the results are shown in Fig. 5. In addition, the turnover frequency of Example 3, in which the number of cyclic voltammetry cycles was 400, is compared with other ammonia decomposition catalysts currently reported and is shown in Fig. 6.

[0084] - GC-TCD

[0085] - Carrier gas: He for hydrogen measurement, Ar for ammonia measurement

[0086] - Oven conditions: 50℃ → 10℃ / min → 250℃ → -10℃ / min → 50℃

[0087] Referring to FIG. 5, in the case of Examples 1 to 3, although the content of Ru metal was very low at 0.41 to 0.59% based on the weight of the entire catalyst, the catalyst was produced at a low temperature (500°C) and a high ammonia supply rate (60 L g cat -1 h -1 ) it can be confirmed that the ammonia conversion rate is about 30% or more. Furthermore, referring to Fig. 6, in the case of Example 3 where the number of cyclic voltage current deposition cycles is 400, the conversion rate is about 20,000 h. -1 It can be confirmed that the catalyst exhibits the highest level of catalytic activity compared to other ammonia decomposition catalysts currently reported, showing a turnover frequency of .

[0088] This can be judged to be because even with a small amount of Ru metal, the Ru metal is deposited through the cyclic voltammetric deposition method and is evenly and thinly supported on the surface of the support, resulting in a high ammonia conversion efficiency. In addition, since Example 3, which has 400 cyclic voltage cycles, shows the highest ammonia decomposition conversion rate among the Examples, it can be confirmed that as the cyclic voltammetric deposition progresses, the amount of Ru metal selectively deposited on the surface of the support increases, thereby increasing the catalytic activity.

[0089] Meanwhile, referring to FIG. 5, in the case of Comparative Example 1, as confirmed above, Ru metal deposition at a level suitable for use as an ammonia decomposition catalyst was not achieved, and thus the ammonia conversion rate was significantly lower than in Examples 1 to 3. In the case of Comparative Example 2, although the Ru metal loading amount was the highest, as confirmed through FIG. 3, the ammonia conversion rate was lower than in Examples 1 to 3 due to structural loss of the support itself.

Claims

1. In a method for manufacturing a catalyst for ammonia decomposition, A step of preparing a metal precursor aqueous solution and a porous support, respectively; and A step of forming a metal-support complex by supporting the metal of the metal precursor aqueous solution on the surface of a porous support using a cyclic voltametric electrodeposition method; A method for producing an ammonia decomposition catalyst, wherein the metal is contained in an amount of 0.3 to 3.0 wt% based on the total weight of the ammonia decomposition catalyst.

2. In paragraph 1, A method for producing a catalyst for ammonia decomposition, wherein the porous support is pretreated by a pretreatment step including a washing step and a drying step.

3. In paragraph 1, A method for producing a catalyst for ammonia decomposition, further comprising a step of drying the metal-support complex; and a step of calcining the dried metal-support complex.

4. In paragraph 1, A method for producing an ammonia decomposition catalyst, wherein the step of preparing the above metal precursor aqueous solution includes a step of adjusting the pH to 0.1 to 2.0 by adding an acidic solution.

5. In paragraph 4, A method for producing a catalyst for ammonia decomposition, wherein the acidic solution comprises at least one selected from the group consisting of perchloric acid, nitric acid, hydrochloric acid, and sulfuric acid.

6. In paragraph 1, A method for producing a catalyst for ammonia decomposition, wherein the concentration of the metal precursor contained in the above metal precursor aqueous solution is 1 mM to 0.1 M.

7. In paragraph 1, A method for producing an ammonia decomposition catalyst, wherein the above cyclic voltage current deposition is performed 100 to 500 times.

8. In paragraph 1, A method for producing a catalyst for ammonia decomposition, wherein the above cyclic voltammetry is performed in a potential range of -0.6 to 0.4 V.

9. In paragraph 1, A method for producing an ammonia decomposition catalyst, wherein the above cyclic voltammetric current deposition is performed at a potential change rate of 1 mV / s to 500 mV / s.

10. In paragraph 1, A method for producing a catalyst for ammonia decomposition, wherein the metal of the above metal precursor aqueous solution is at least one metal selected from the group consisting of Ru, Pt, Ir, Pd, Ni, Al, Mg, K, Na, Rb, Cs, Ca, Sr, Ba, La, Pr and Ce.

11. In paragraph 1, The above metal precursors are RuCl3, RuCl3·xH2O, RuCl3·3H2O, [Ru(NH3)6]Cl2, Ru3(CO) 12 , [Ru(CO)3Cl2]2, C 16 H 22 O2Ru, C 18 H 26 A method for producing a catalyst for decomposing ammonia, the catalyst comprising at least one ruthenium metal precursor selected from the group consisting of Ru, Ru(NO)(NO3)x(OH)y (wherein x+y=3), I3Ru, Ru(C5H7O2)3, K4Ru(CN)6·xH2O, RuO2·xH2O, RuO2, KRuO4, and K2RuCl6.

12. In paragraph 1, A method for producing a catalyst for decomposing ammonia, wherein the porous support is at least one porous support selected from the group consisting of nickel foam (Ni foam), nickel mesh (Ni mesh), copper foam (Cu foam), copper mesh (Cu mesh), titanium foam (Ti foam), titanium mesh (Ti mesh), aluminum foam (Al foam), aluminum mesh (Al mesh), graphene foam (Graphene foam), graphene mesh (Graphene mesh), carbon paper (Carbon paper), carbon felt (Carbon felt), and carbon foam (Carbon foam).

13. In paragraph 1, A method for producing an ammonia decomposition catalyst, wherein the above cyclic voltammetric deposition is performed using the porous support as the working electrode, a graphite rod as the counter electrode, and silver / silver chloride (Ag / AgCl) as the reference electrode.

14. Contains a porous support and a metal supported on the surface of the porous support by cyclic voltametric electrodeposition, A catalyst for ammonia decomposition, wherein the metal is contained in an amount of 0.3 to 3.0 wt% based on the total weight of the catalyst.

15. In paragraph 14, A catalyst for ammonia decomposition, wherein the average particle size of the above metal is 10 to 70 nm.

16. In paragraph 14, A catalyst for ammonia decomposition, wherein the metal is at least one metal selected from the group consisting of Ru, Pt, Ir, Pd, Ni, Al, Mg, K, Na, Rb, Cs, Ca, Sr, Ba, La, Pr and Ce.

17. In paragraph 14, A catalyst for ammonia decomposition, wherein the porous support is at least one porous support selected from the group consisting of nickel foam (Ni foam), nickel mesh (Ni mesh), copper foam (Cu foam), copper mesh (Cu mesh), titanium foam (Ti foam), titanium mesh (Ti mesh), aluminum foam (Al foam), aluminum mesh (Al mesh), graphene foam (Graphene foam), graphene mesh (Graphene mesh), carbon paper (Carbon paper), carbon felt (Carbon felt), and carbon foam (Carbon foam).

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