Ruthenium-nickel foam composite catalyst, method of manufacturing same and hydrogen extraction system using same

Abstract

A ruthenium-nickel foam composite catalyst, a method for manufacturing the same, and a hydrogen extraction system (10) using the same are disclosed. More specifically, a method for manufacturing a catalyst composite for use in ammonia decomposition is provided, comprising: (a) a step of pre-treating a porous support having the shape of a three-dimensional structure containing pores and containing a first metal by contacting said porous support with an acidic aqueous solution; (b) a step of preparing a second metal precursor aqueous solution containing water and a second metal precursor containing a second metal; and (c) a step of manufacturing a catalyst composite by supporting a catalyst containing a second metal on part or all of the surface of said porous support using said pre-treated porous support and said second metal precursor aqueous solution. The present invention can provide a low-content precious metal catalyst by maximizing the utilization of the supported precious metal through the selective adsorption of Ru metal.

Description

Technology Field

[0001] The present invention relates to a ruthenium-nickel foam composite catalyst, a method for manufacturing the same, and a hydrogen extraction system using the same. Background Technology

[0002] Ammonia has a high hydrogen storage capacity relative to weight (17.6 wt.%) and a high energy density relative to volume (12.8 MJ / L, 120 kg-H2 / m³). 3 Ammonia is attracting attention as a promising hydrogen carrier for the import of overseas hydrogen due to its characteristics of easy liquefaction (approximately 10 bar at room temperature). Since ammonia consists only of hydrogen and nitrogen, it enables carbon-free hydrogen production, and it is being considered as the most likely carrier for the import of overseas hydrogen in accordance with the Basic Plan for the Implementation of the Hydrogen Economy and the Hydrogen Economy Activation Roadmap announced by the government.

[0003] The thermochemical ammonia decomposition hydrogen extraction reaction equation, currently undergoing active research and development both domestically and internationally, is NH3 → 0.5 N2 + 1.5 H2 (ΔH = 46 kJ / mol). As this is an endothermic reaction, hydrogen production is possible through the supply of an external heat source. Complete conversion of ammonia to hydrogen requires high-temperature reaction conditions of over 600 ℃ at 1 atmosphere and highly active ammonia decomposition catalysts. Additionally, there is the issue of requiring separate separation processes (Removal of Unreacted Ammonia (TSA) and Removal of Nitrogen (PSA)). Electrochemical methods, which serve as an alternative to thermochemical hydrogen generation, are broadly categorized into two types: anhydrous ammonia (ammonia purity > 99.0%) electrolysis systems and ammonia water electrolysis systems. Since the ammonia water electrolysis method involves dissolving ammonia in water (0.025–3 M) for electrolysis, it has disadvantages such as the need for ultra-high purity distilled water and the requirement to use KOH of 1 M or higher as a supporting electrolyte (which cannot be recovered or reused); furthermore, due to the oxygen present in the water, NO XDue to the problem of side reactions generating harmful substances, there are limitations to applying this to large-scale hydrogen extraction using massive amounts of ammonia imported from overseas. On the other hand, the anhydrous ammonia electrolysis used in this invention is a system that directly electrolyzes imported liquefied ammonia by mixing it with an auxiliary electrolyte (0.5 - 2 M) under pressurized conditions, and through a reaction under oxygen-free conditions, NO X Side reactions such as [the above] can be blocked, and the entire amount of auxiliary electrolyte used can be recovered and reused, making economical hydrogen production possible.

[0004] Therefore, the development of high-efficiency catalysts for this purpose is necessary. To achieve this economically and efficiently, it is required to develop electrode catalysts that possess advantages such as the use of very inexpensive supports, minimized precious metal content, easy large-area fabrication, and simple manufacturing methods. Furthermore, since reactors and systems for evaluating the catalysts and electrodes to be used in the reaction are currently unavailable, the development of related technologies is necessary. The problem to be solved

[0005] The objective of the present invention is to solve the aforementioned problems by providing a catalyst with a low precious metal content through the maximization of the utilization of supported precious metals via the selective adsorption of Ru metal.

[0006] Another objective of the present invention is to provide a method for manufacturing an ammonia decomposition catalyst using an electrodeposition method, which enables the production of a desired metal on a structural support in an easy and rapid manner.

[0007] Another objective of the present invention is to provide an anhydrous ammonia electrolysis system capable of controlling temperature, pressure, and the flow rate of anhydrous ammonia, measuring the flow rate and composition of the gas generated after the reaction, and efficiently evaluating the activity of the electrode. means of solving the problem

[0008] According to one aspect of the present invention, a method for preparing a catalyst composite for use in ammonia decomposition is provided, comprising: (a) a step of pretreating a porous support having the shape of a three-dimensional structure including pores and including a first metal by contacting said porous support with an acidic aqueous solution; (b) a step of preparing a second metal precursor aqueous solution including water and a second metal precursor including a second metal; and (c) a step of preparing a catalyst composite by supporting a catalyst including a second metal on a part or all of the surface of said porous support using said pretreated porous support and said second metal precursor aqueous solution.

[0009] Additionally, the above step (a) may include (a-1) a step of washing a porous support having the shape of a three-dimensional structure containing pores and containing a first metal with an acidic aqueous solution; and (a-2) a step of drying the washed porous support.

[0010] In addition, the first metal may include one or more selected from the group consisting of nickel (Ni), copper (Cu), titanium (Ti), ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), palladium (Pd), cobalt (Co), molybdenum (mo), zinc (Zn), chromium (Cr), manganese (Mn), tungsten (W), iron (Fe), stainless steel (SUS), aluminum (Al), and alloys thereof.

[0011] In addition, the porous support may include one or more selected from the group consisting of nickel foam (Ni foam), nickel mesh (Ni mesh), copper (Cu) foam, copper mesh, titanium (Ti) foam, titanium mesh, aluminum (Al) foam, aluminum mesh, graphene foam, graphene mesh, carbon paper, carbon felt, and carbon foam.

[0012] In addition, the above acidic aqueous solution may include one or more selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid.

[0013] In addition, the second metal precursor aqueous solution of step (b) may additionally contain perchloric acid.

[0014] In addition, the second metal precursor may include one or more selected from the group consisting of Ru, Pt, Ir, Pd, Ni, Al, Mg, K, Na, Rb, Cs, Ca, Sr, Ba, La, Pr, and Ce.

[0015] In addition, the second 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 Ru, Ru(NO)(NO3) x (OH) y It may include one or more selected from the group consisting of (where x+y=3), I3Ru, Ru(C5H7O2)3, K4Ru(CN)6·xH2O, RuO2·xH2O, RuO2, KRuO4, and K2RuCl6.

[0016] In addition, the above step (c) can be performed using an electrodeposition method.

[0017] Additionally, the above step (c) may include: (c-1) a step of immersing a working electrode, a counter electrode, and a reference electrode comprising the pretreated porous support in the aqueous solution of the second metal precursor; (c-2) a step of forming a second metal on part or all of the surface of the porous support by performing cyclic voltametric deposition; (c-3) a step of drying the porous support having the second metal formed on the surface; and (c-4) a step of calcining the dried porous support having the second metal formed thereon to produce a catalyst composite having a catalyst containing the second metal supported on part or all of the surface of the porous support.

[0018] In addition, the counter electrode may include a graphite rod, carbon paper, carbon felt, carbon foam, and carbon nanotubes.

[0019] In addition, the reference electrode may include a silver-silver chloride electrode.

[0020] In addition, in step (c-2), the uniformity of the size of the catalyst supported on the porous support can be increased and the thickness of the catalyst can be reduced by repeatedly increasing the number of times the cyclic voltametric deposition is performed.

[0021] In addition, the drying of step (c-3) can be performed at a temperature of 80 to 120 ℃ for 10 to 15 hours.

[0022] In addition, the firing of step (c-4) can be performed at a temperature of 300 to 700 ℃ for 1 to 5 hours under an air atmosphere.

[0023] According to another aspect of the present invention, a catalyst composite for use in ammonia decomposition is provided, comprising: a porous support having the shape of a three-dimensional structure including pores and comprising a first metal; and a catalyst supported on part or all of the surface of the three-dimensional structure and comprising a second metal.

[0024] In addition, the above catalyst may be used to decompose ammonia for the extraction of hydrogen.

[0025] According to another aspect of the present invention, an electrochemical hydrogen extraction system (10) is provided, comprising: a gas supply unit (100) that supplies a gas containing ammonia to a reactor (210) including an ammonia tank (110) for storing ammonia; and a reaction unit (200) that extracts hydrogen by an electrochemical decomposition reaction of the ammonia, the reaction unit (200) which includes a reactor (210) and a second electrode (240) located inside the reactor (210) and including a first electrode (220) and a catalyst complex according to claim 1.

[0026] In addition, the hydrogen extraction system (10) may further include a flow measurement unit (300) including a flow meter (310) and a component analysis unit (400) including a component analyzer (410).

[0027] In addition, the reaction unit (200) may further include a stirrer, a chiller, a water level sensor, a temperature controller (TC), and a vent.

[0028] In addition, the electrochemical reactions of the first electrode and the second electrode can be performed according to Reaction Scheme 1 and Reaction Scheme 2, respectively.

[0029] [Reaction Equation 1]

[0030] First electrode (anode): 6NH2 - → N2(g) + 4NH3(l) + 6e - , NH3→ 1 / 2N2+ 3H + + 3e-

[0031] [Reaction Equation 2]

[0032] Second electrode (cathode): 6NH3(l)+ 6e - → 3H2(g) + 6NH2 - , 3H + + 3e - → 3 / 2H2

[0033] Net: NH3→ 1 / 2N2+ 3 / 2H2

[0034] In addition, the cap and vessel of the reactor (210) can create a pressurized environment using an o-ring.

[0035] In addition, the above cap, vessel, and o-ring may include one or more materials selected from the group consisting of PEEK, FKM, FFKM, PTFE, EDPM, and TFE / P. Effects of the invention

[0036] The present invention can provide a low-content precious metal catalyst by maximizing the utilization of supported precious metals through the selective adsorption of Ru metal.

[0037] In addition, commercial application may be possible through the development of structured catalysts.

[0038] In addition, large-area catalysts can be synthesized easily and quickly using a simple synthesis method, and are also suitable for mass production.

[0039] In addition, the reaction temperature, pressure, and flow rate of anhydrous ammonia can be controlled, and the reaction efficiency (Faradic Efficiency) can be calculated by measuring the flow rate and composition of the gas generated after the reaction, and an anhydrous ammonia electrolysis system for evaluating the activity of an efficient electrode can be provided. Brief explanation of the drawing

[0040] These drawings are for reference to explain exemplary embodiments of the present invention, and therefore, the technical concept of the present invention should not be interpreted as being limited to the attached drawings. Figure 1a is a photograph of the actual catalyst produced according to the present invention, showing the large-area (6 cm x 6 cm) ammonia decomposition catalyst of Example 3. The left side of FIG. 1b shows the Ni foam before synthesis, which is Comparative Example 1, and the right side shows the Ru / Ni foam (2cm x 3cm) after synthesis, which is Example 3. Figure 2 shows the Ru / Ni foam (electrode) catalyst electrodeposition system of the present invention. Figure 3 shows an SEM image of the Ru(n) / Ni(electrode) catalyst of the present invention. Figure 4 shows the EDS mapping of the Ru(400) / Ni(electrode) catalyst of Example 3 of the present invention. Figure 5 shows the electrochemical anhydrous ammonia electrolysis system PFD. Figure 6 shows the Gas supply system P&ID in an electrochemical anhydrous ammonia electrolysis system. Figure 7 shows the Reactor Cap P&ID in an electrochemical anhydrous ammonia electrolysis system. Figure 8 shows the evaluation of the Ru(n) / Ni electrode catalyst using CV. FIG. 9 shows the 50-hour continuous evaluation (chronoamperometry, constant voltage method) of the Ru(200) / Ni electrode of Example 2 of the present invention. Specific details for implementing the invention

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention.

[0042] However, the following description is not intended to limit the present invention to specific embodiments, and detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions could obscure the essence of the present invention.

[0043] The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to indicate the presence of the features, numbers, steps, actions, components, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, or combinations thereof.

[0044] Additionally, terms including ordinal numbers, such as "first," "second," etc., used below may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0045] Furthermore, when it is stated that a component is "formed" or "laminated" on another component, it should be understood that while it may be formed or laminated by being directly attached to the entire surface or one surface of the other component, there may also be other components present in between.

[0046] Hereinafter, the ruthenium-nickel foam composite catalyst of the present invention, the method for manufacturing the same, and a hydrogen extraction system using the same will be described in detail. However, this is presented as an example and is not intended to limit the present invention, and the present invention is defined only by the scope of the claims set forth below.

[0047] A method for manufacturing a catalyst composite for use in ammonia decomposition is provided, comprising: (a) a step of pre-treating a porous support having the shape of a three-dimensional structure including pores and containing a first metal by contacting said porous support with an acidic aqueous solution; (b) a step of preparing a second metal precursor aqueous solution containing water and a second metal precursor containing a second metal; and (c) a step of manufacturing a catalyst composite by supporting a catalyst containing a second metal on part or all of the surface of said porous support using said pre-treated porous support and said second metal precursor aqueous solution.

[0048] Additionally, the above step (a) may include (a-1) a step of washing a porous support having the shape of a three-dimensional structure containing pores and containing a first metal with an acidic aqueous solution; and (a-2) a step of drying the washed porous support.

[0049] In addition, the first metal may include one or more selected from the group consisting of nickel (Ni), copper (Cu), titanium (Ti), ruthenium (Ru), platinum (Pt), gold (Au), silver (Ag), palladium (Pd), cobalt (Co), molybdenum (mo), zinc (Zn), chromium (Cr), manganese (Mn), tungsten (W), iron (Fe), stainless steel (SUS), aluminum (Al) and alloys thereof, preferably nickel (Ni).

[0050] In addition, the porous support may include one or more selected from the group consisting of nickel foam (Ni foam), nickel mesh (Ni mesh), copper (Cu) foam, copper mesh, titanium (Ti) foam, titanium mesh, aluminum (Al) foam, aluminum mesh, graphene foam, graphene mesh, carbon paper, carbon felt, and carbon foam, preferably one or more selected from the group consisting of nickel foam (Ni foam), copper (Cu) foam, and aluminum (Al) foam.

[0051] In addition, the above acidic aqueous solution may include one or more selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid.

[0052] In addition, the aqueous solution of the second metal precursor in step (b) may further include perchloric acid. In addition, it may include a chloride-based or nitrate-based compound containing perchloric acid.

[0053] In addition, the pH can be adjusted by adding perchloric acid (HClO4) in an amount of 0.01 to 1 M, preferably 0.1 M.

[0054] In addition, the second metal precursor may include one or more selected from the group consisting of Ru, Pt, Ir, Pd, Ni, Al, Mg, K, Na, Rb, Cs, Ca, Sr, Ba, La, Pr, and Ce, preferably Ru.

[0055] In addition, the second 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 Ru, Ru(NO)(NO3) x (OH) yIt may include one or more selected from the group consisting of (where x+y=3), I3Ru, Ru(C5H7O2)3, K4Ru(CN)6·xH2O, RuO2·xH2O, RuO2, KRuO4, and K2RuCl6.

[0056] In addition, the above step (c) can be performed using an electrodeposition method. Specifically, to maximize the participation of the supported Ru metal in the reaction for an efficient ammonia decomposition reaction, it can be selectively attached to the surface of a support. A catalyst is provided in which ruthenium metal is supported on nickel foam using electrodeposition for the selective surface attachment of Ru metal (precursor: RuCl3·xH2O). This not only enables a reaction at room temperature but also allows for hydrogen and nitrogen separation when a reactor equipped with a separation membrane is adopted, thereby eliminating the need for a separate separation process after the reaction.

[0057] In addition, since the electrode deposition method is used, it has the feature of being able to reproducibly manufacture electrodes ranging from small to large sizes (e.g., 6x6 cm or larger) using the same method.

[0058] Furthermore, the anhydrous ammonia electrolysis method of the present invention does not use water, so there are no side reactions such as NOX. Since there are no side reactions, the cell voltage is lower compared to water electrolysis, resulting in high hydrogen generation efficiency. Additionally, it features the characteristic of enabling 100% recycling of the supporting electrolyte added during the reaction. In the case of water electrolysis and ammonia water electrolysis systems, high concentrations of KOH are introduced, but recovery after the reaction is impossible.

[0059] Additionally, the above step (c) may include: (c-1) a step of immersing a working electrode, a counter electrode, and a reference electrode comprising the pretreated porous support in the aqueous solution of the second metal precursor; (c-2) a step of forming a second metal on part or all of the surface of the porous support by performing cyclic voltametric deposition; (c-3) a step of drying the porous support having the second metal formed on the surface; and (c-4) a step of calcining the dried porous support having the second metal formed thereon to produce a catalyst composite having a catalyst containing the second metal supported on part or all of the surface of the porous support.

[0060] In addition, in the above electrodeposition, the anode is a support, and the cathode may include a carbon series.

[0061] In addition, the counter electrode may include a graphite rod, carbon paper, carbon felt, carbon foam, and carbon nanotubes, preferably a graphite rod.

[0062] In addition, the reference electrode may include a silver-silver chloride electrode.

[0063] In addition, the potential range in the above-mentioned electrodeposition may be -0.4 to 0.2 V.

[0064] In addition, in step (c-2), the uniformity of the size of the catalyst supported on the porous support can be increased and the thickness of the catalyst can be reduced by repeatedly increasing the number of times the cyclic voltametric deposition is performed.

[0065] In addition, the drying of step (c-3) can be performed at a temperature of 80 to 120 ℃ for 10 to 15 hours.

[0066] In addition, the firing of step (c-4) can be performed at a temperature of 300 to 700 ℃ for 1 to 5 hours under an air atmosphere.

[0067] In addition, in step (c-4), the efficiency of the electrode catalyst can be changed by varying the calcination temperature.

[0068] FIG. 1a is a photograph of the actual catalyst fabricated according to the present invention, showing the large-area (6 cm x 6 cm) ammonia decomposition catalyst of Example 3; FIG. 1b shows the Ni foam before synthesis on the left and the Ru / Ni foam (2 cm x 3 cm) of Example 3 after synthesis on the right; FIG. 2 shows the electrodeposition system of the Ru / Ni foam (electrode) catalyst of the present invention; FIG. 3 shows an SEM image of the Ru(n) / Ni (electrode) catalyst of the present invention; and FIG. 4 shows the EDS mapping of the Ru(400) / Ni (electrode) catalyst of Example 3 of the present invention.

[0069] Referring to FIGS. 1 to 4, the present invention provides a catalyst composite for use in ammonia decomposition comprising: a porous support having the shape of a three-dimensional structure including pores and comprising a first metal; and a catalyst supported on part or all of the surface of the three-dimensional structure and comprising a second metal.

[0070] In addition, the above catalyst may be used to decompose ammonia for the extraction of hydrogen.

[0071] In addition, the above ammonia may be anhydrous ammonia.

[0072] Figure 5 shows the PFD of the electrochemical anhydrous ammonia electrolysis system, Figure 6 shows the Gas supply system P&ID within the electrochemical anhydrous ammonia electrolysis system, and Figure 7 shows the Reactor Cap P&ID within the electrochemical anhydrous ammonia electrolysis system.

[0073] Referring to FIGS. 5 to 7, the present invention provides an electrochemical hydrogen extraction system (10) comprising: a gas supply unit (100) that supplies a gas containing ammonia to a reactor (210) including an ammonia tank (110) for storing ammonia; and a reaction unit (200) that extracts hydrogen by an electrochemical decomposition reaction of ammonia, the reaction unit (200) including a reactor (210) and a second electrode (240) located inside the reactor (210) and including a first electrode (220) and a catalyst complex according to claim 1.

[0074] In addition, the hydrogen extraction system (10) may further include a flow measurement unit (300) including a flow meter (310) and a component analysis unit (400) including a component analyzer (410).

[0075] In addition, the hydrogen extraction system (10) can control the pressure and flow rate to reduce the pressure after the reaction in the reactor, and measure the efficiency by measuring the flow rate in a flow meter using the generated hydrogen.

[0076] In addition, Hx in FIG. 5 is a heat exchanger, and by-products such as water can be collected through heat exchange before flow rate measurement. Water and residual ammonia can be collected by cooling and liquefying them through the heat exchanger for the purpose of protecting the MFM and GC.

[0077] In addition, the reaction unit (200) may further include a stirrer, a chiller, a water level sensor, a temperature controller (TC), and a vent.

[0078] Referring to FIGS. 5 and 6, the ammonia supplied in the anhydrous ammonia evaluation system of the present invention utilizes a purity of > 99.0%. By utilizing the gas supply system shown in FIG. 6, gases such as nitrogen and argon can be used for carrier gas supply, purge, etc., for GC-TCD measurement.

[0079] The reaction process may include: (1) a step of using a back pressure regulator to create a pressurized environment and controlling the pressure to a range of 1 to 10 bar, and separating unreacted ammonia using water, sulfuric acid, etc. at the downstream end; (2) a step of removing residual ammonia and moisture through a heat exchanger and separating the collected water through a vessel; (3) a step of measuring the flow rate of the discharged gas through an MFM; and (4) a step of moving the gas to a GC using a metering pump to perform component analysis.

[0080] In this case, regarding the reactor, a system for the electrolysis of anhydrous ammonia is absent, and there is no system capable of analyzing the efficiency of hydrogen production by electrolysis under high pressure. Therefore, a vessel capable of safely analyzing anhydrous ammonia, which exhibits highly corrosive characteristics under high pressure, and a system for such analysis were developed.

[0081] In addition, the reactor is made of SUS material to create a safe pressurized environment, and an internal Teflon cup is utilized to prevent direct contact between anhydrous ammonia and SUS to prevent ammonia corrosion.

[0082] In addition, the reactor cap must also be made of Teflon to prevent corrosion. As an alternative to Teflon, it is also possible to use quartz, which can withstand pressures of 10 bar or higher. O-rings are used for the reactor vessel and cap to create a pressurized environment, and to prevent corrosion, non-fluorinated O-rings should use PEEK, while fluorinated O-rings should use FKM, FFKM, PTFE, EDPM, or TFE / P. Furthermore, the system can utilize an agitator, stirring of the supporting electrolyte, use a corrosion-resistant level sensor for internal level detection, power supply and measurement using insulating fittings, a TC for measuring reactor temperature, a back pressure regulator for depressurization after the reaction, and subsequently, an unreacted ammonia purification device and measurement of flow rate and composition.

[0083] In addition, to control the internal temperature of the reactor, the reactor can be configured with a double-pipe line to allow cooling water to flow externally, thereby enabling temperature control. Here, the controllable temperature range is -60 to +30 ℃.

[0084] Referring to Fig. 7, the diagram shows a reactor cap, and the perforations in this area allow elements necessary for the electrochemical reaction to be inserted into the reactor. Additionally, a SUS cap is used, and a Teflon cap can be added inside to prevent corrosion. The electrode is positioned in the electrode section of Fig. 7 and can be utilized as a working, counter, or reference electrode depending on the type of experiment. SUS fittings are used for sealing the electrode, and for insulation, non-conductive materials such as PTFE are used for the ferrules. Furthermore, the internal water level can be monitored using a water level sensor. The reactants are stirred using a stirrer, the internal temperature is measured and controlled using a TC, the reactants are supplied through the inlet, and the products are discharged through the outlet.

[0085] In addition, the electrochemical reactions of the first electrode and the second electrode can be performed according to Reaction Scheme 1 and Reaction Scheme 2, respectively.

[0086] [Reaction Equation 1]

[0087] First electrode (anode): 6NH2 - → N2(g) + 4NH3(l) + 6e - , NH3→ 1 / 2N2+ 3H + + 3e -

[0088] [Reaction Equation 2]

[0089] Second electrode (cathode): 6NH3(l)+ 6e - → 3H2(g) + 6NH2 - , 3H + + 3e - → 3 / 2H2

[0090] Net: NH3→ 1 / 2N2+ 3 / 2H2

[0091] The present invention relates to the case of electrochemical decomposition of ammonia anhydride and hydrogen extraction, An anhydrous ammonia electrolysis system was developed for efficient electrode activity evaluation. Specifically, the electrochemical anhydrous ammonia hydrogen extraction system of the present invention developed a supply system to prevent loss due to pressure reduction during the transfer of anhydrous ammonia from the cylinder to the reactor. This system prevents pressure reduction by controlling the supply pressure through a pressure and flow rate control system, and can supply a desired flow rate through a flow rate controller usable under high pressure conditions.

[0092] In addition, the temperature, pressure, and flow rate of anhydrous ammonia can be controlled, and the flow rate and composition of the gas produced after the reaction can be measured.

[0093] Unlike the vaporization, high-temperature process, and separation of unreacted materials and products, which are essential processes of thermochemical methods, the present invention can simply produce hydrogen through an immediate electrolysis method without undergoing complex processes.

[0094] [Example]

[0095] Hereinafter, preferred embodiments of the present invention will be described. However, this is for illustrative purposes only and does not limit the scope of the present invention.

[0096] Example: Fabrication of electrode catalyst using electrodeposition technique

[0097] Example 1: Ru(100) / Ni foam, 100 cycles of cyclic voltammetry deposition

[0098] In an embodiment of the present invention, the catalyst preparation process involved fabricating a (electrode) catalyst using an electrodeposition technique with a potentiostat. Ruthenium chloride hydride and perchloric acid were added to distilled water (tertiary, 17–18.2 MΩ·cm) to concentrations of 10 mM and 0.1 M, respectively. The prepared solution was added to distilled water, diluted, and stirred at room temperature for at least one hour to prepare a precursor solution.

[0099] The nickel foam was washed in a 5 M hydrochloric acid solution for 15 minutes. After removing the hydrochloric acid solution from the washed nickel foam using distilled water, the support was pretreated by drying it in a 100 ℃ oven.

[0100] Pretreated nickel foam, graphite rod, and silver-silver chloride electrodes were connected to the working electrode, counter electrode, and reference electrode, respectively, and then immersed in the prepared precursor solution to ensure the electrodes were sufficiently submerged. Cyclic voltametric (CV) deposition was performed 100 times using a potentiostat in a potential range of -0.4 V to 0.2 V. The supported (electrode) catalyst was dried in a vacuum oven at 100 °C for 12 hours and then collected. The dried metal was calcined at 500 °C for 2 hours in an air atmosphere to perform metal support (electrodeposition method).

[0101] Example 2: Ru(200) / Ni foam, 200 cycles of cyclic voltammetry deposition

[0102] Ru(200) / Ni foam was prepared in the same manner as in Example 1, except that cyclic voltametric deposition was performed 200 times instead of 100 times.

[0103] Example 3: Ru(400) / Ni foam, 400 cycles of cyclic voltammetry deposition performed

[0104] Ru(400) / Ni foam was prepared in the same manner as in Example 1, except that cyclic voltametric deposition was performed 400 times instead of 100 times.

[0105] Comparative Example 1: Ni-foam not containing Ru

[0106] Ni foam was prepared in the same manner as in Example 1, except that Ru was not electrodeposited.

[0107] Table 1 below summarizes the number of Ru electrodeposition cycles according to Examples 1 to 3 and Comparative Example 1.

[0108] division Electrodeposition frequency Example 1 100 Example 2 200 Example 3 400 Comparative Example 1 -

[0109] [Test Example]

[0110] Test Example 1: Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) Analysis

[0111] The amount of Ru loaded was determined through ICP-OES analysis and is shown in Table 2 below.

[0112] division Catalyst name Ru content(wt.%) Example 1 Ru(100) / Ni foam 0.45 Example 2 Ru(200) / Ni foam 0.51 Example 3 Ru(400) / Ni foam 0.59

[0113] According to Table 2 above, quantitative analysis of Ru metal revealed that the metal loading increased by approximately 15% per 100 cycles. This was confirmed to be because, during the deposition process, Ru metal does not continuously adhere, but rather the charge of the support material repeatedly changes between + and - due to the CV cycle, causing the metal to detach and reattach repeatedly.

[0114] Test Example 2: Characterization of Catalyst (SEM Analysis and EDS Mapping)

[0115] Figure 3 shows an SEM image of the Ru(n) / Ni(electrode) catalyst of the present invention, and Figure 4 shows an EDS mapping of the Ru(400) / Ni(electrode) catalyst of Example 3 of the present invention.

[0116] Referring to Figures 3 and 4, it can be seen that the size of the Ru metal lumps supported on the SEM image is approximately 50–70 nm at 100 cycles (Example 1), 30–60 nm at 200 cycles (Example 2), and less than 10 nm (< 10 nm) or 10–30 nm at 400 cycles (Example 3). It was confirmed that the thickness of Ru decreases as the number of CV cycles increases. This indicates that the process of Ru metal attaching and detaching is repeated as the positive and negative states continuously repeat during the catalyst deposition process. Furthermore, it can be inferred that the Ru metal spreads evenly and thinly across the support as the number of cycles increases.

[0117] Test Example 3: Electrochemical Decomposition Analysis of Anhydrous Ammonia (Chronoamperometry, Constant Voltage Method)

[0118] Figure 8 shows the evaluation of a Ru(n) / Ni electrode catalyst using CV, and Figure 9 shows the 50-hour continuous evaluation (Chronoamperometry, constant voltage method) of the Ru(200) / Ni electrode of Example 2 of the present invention.

[0119] Referring to Figures 8 and 9, it was confirmed that both the oxidation and reduction electrode characteristics increased compared to Ni-foam under air calcination conditions. Under an anhydrous ammonia environment (3 ℃, 5 atm) and a constant voltage of -0.8 V, it was confirmed that the efficiency was maintained without a decrease in current for about 50 hours, exhibiting a current efficiency of approximately 95%. In addition, no byproducts other than the generated hydrogen and nitrogen were detected, and the hydrogen production rate per hour was approximately 48 mL / h.

[0120] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 (a) a step of pretreating a porous support having the shape of a three-dimensional structure including pores and containing a first metal by contacting said porous support with an acidic aqueous solution; (b) a step of preparing a second metal precursor aqueous solution containing water and a second metal precursor containing a second metal; and (c) a step of preparing a catalyst composite by supporting a catalyst containing a second metal on part or all of the surface of said porous support using said pretreated porous support and said second metal precursor aqueous solution; wherein step (c) comprises: (c-1) a step of immersing a working electrode, a counter electrode, and a reference electrode containing said pretreated porous support in said second metal precursor aqueous solution; (c-2) a step of forming a second metal on part or all of the surface of said porous support by performing cyclic voltametric deposition; and (c-3) a step of drying said porous support having said second metal formed on the surface. and (c-4) a step of calcining the porous support on which the dried second metal is formed to produce a catalyst composite in which a catalyst comprising the second metal is supported on part or all of the surface of the porous support; wherein, in step (c-2), the number of times the cyclic voltametric deposition is performed is repeatedly increased to increase the uniformity of the size of the catalyst supported on the porous support and to decrease the thickness of the catalyst, and wherein the first metal comprises nickel (Ni) and the second metal comprises ruthenium (Ru). Claim 2 A method for manufacturing a catalyst composite according to claim 1, wherein step (a) comprises: (a-1) washing a porous support having the shape of a three-dimensional structure including pores and including a first metal with an acidic aqueous solution; and (a-2) drying the washed porous support. Claim 3 delete Claim 4 A method for manufacturing a catalyst composite according to claim 1, characterized in that the porous support comprises nickel foam (Ni foam). Claim 5 A method for manufacturing a catalyst complex according to claim 1, characterized in that the acidic aqueous solution comprises one or more selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid. Claim 6 A method for manufacturing a catalyst complex according to claim 1, characterized in that the aqueous solution of the second metal precursor in step (b) further comprises perchloric acid. Claim 7 A method for manufacturing a catalyst complex according to claim 1, characterized in that the second metal precursor comprises Ru. Claim 8 In claim 1, the second 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 Ru, Ru(NO)(NO3) x (OH) y A method for preparing a catalyst complex characterized by comprising one or more selected from the group consisting of (where x+y=3), I3Ru, Ru(C5H7O2)3, K4Ru(CN)6·xH2O, RuO2·xH2O, RuO2, KRuO4, and K2RuCl6. Claim 9 A method for manufacturing a catalyst composite according to claim 1, characterized in that step (c) is performed using an electrodeposition method. Claim 10 delete Claim 11 delete Claim 12 A method for manufacturing a catalyst composite for use in ammonia decomposition according to claim 1, comprising: a porous support having the shape of a three-dimensional structure including pores and comprising a first metal; and a catalyst supported on part or all of the surface of the three-dimensional structure and comprising a second metal. Claim 13 A method for manufacturing a catalyst complex according to claim 1, characterized in that the catalyst complex is used to decompose ammonia for the extraction of hydrogen. Claim 14 An electrochemical hydrogen extraction system (10) comprising: a gas supply unit (100) that supplies a gas containing ammonia to a reactor (210) including an ammonia tank (110) for storing ammonia; and a reaction unit (200) that extracts hydrogen by an electrochemical decomposition reaction of the ammonia, the reaction unit (200) which includes a reactor (210) and a second electrode (240) located inside the reactor (210) and including a first electrode (220) and a catalyst complex; wherein the catalyst complex has the shape of a three-dimensional structure including pores and comprises a porous support including nickel (Ni); and a catalyst including ruthenium (Ru) which is supported on part or all of the surface of the three-dimensional structure. Claim 15 An electrochemical hydrogen extraction system according to claim 14, wherein the hydrogen extraction system (10) further comprises a flow measurement unit (300) including a flow meter (310) and a component analysis unit (400) including a component analyzer (410). Claim 16 An electrochemical hydrogen extraction system according to claim 14, characterized in that the reaction unit (200) further comprises a stirrer, a chiller, a water level sensor, a temperature controller (TC), and a vent. Claim 17 An electrochemical hydrogen extraction system according to claim 14, characterized in that the electrochemical reactions of the first electrode and the second electrode are performed according to Reaction Equation 1 and Reaction Equation 2, respectively. [Reaction Equation 1] First electrode (anode): 6NH2 - → N2(g) + 4NH3(l) + 6e - , NH3→ 1 / 2N2+ 3H + + 3e - [Reaction Equation 2] Second electrode (cathode): 6NH3(l) + 6e - → 3H2(g) + 6NH2 - , 3H + + 3e - → 3 / 2H2Net: NH3→ 1 / 2N2+ 3 / 2H2 Claim 18 An electrochemical hydrogen extraction system according to claim 14, characterized by including insulating fittings to prevent short circuits for decomposing liquefied ammonia under high pressure conditions. Claim 19 An electrochemical hydrogen extraction system according to claim 14, characterized in that the cap and vessel of the reactor (210) create a pressurized environment using an o-ring. Claim 20 An electrochemical hydrogen extraction system according to claim 19, characterized in that the cap, vessel, and o-ring comprise one or more materials selected from the group consisting of PEEK, FKM, FFKM, PTFE, EDPM, and TFE / P.

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