Reaction cell for ammonia electrolysis reaction and electrochemical hydrogen extraction system comprising same

Abstract

A reaction cell for an ammonia electrolysis reaction and an electrochemical hydrogen extraction system including same are disclosed. Specifically, a reaction cell (10) for use in an ammonia electrolysis reaction is provided, the reaction cell (10) comprising: an anode (100) comprising a first metal; a cathode (200) comprising a second metal; and a separator (300) positioned between the anode and the cathode and comprising a cation exchange membrane (310). The present invention provides a hydrogen production technology based on anhydrous ammonia electrolysis through cation exchange, thereby enabling production of high-purity, high-pressure hydrogen with low energy consumption.

Description

Reaction cell for ammonia electrolysis reaction and electrochemical hydrogen extraction system including the same

[0001] The present invention relates to a reaction cell for ammonia electrolysis and an electrochemical hydrogen extraction system comprising the same.

[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 classified into two types: anhydrous ammonia (ammonia purity > 99.0%, pure ammonia not dissolved in water or solvents) 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 use of KOH with a concentration 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 X Due to the problem of side reactions that generate harmful substances, there are limitations to its application in large-scale hydrogen extraction using massive amounts of ammonia imported from overseas.

[0004] Therefore, there is a need to develop technology that simplifies the thermochemical ammonia hydrogen production process to reduce costs, and enables improved energy efficiency and cost reduction in hydrogen production through a lower theoretical voltage compared to water electrolysis.

[0005] The objective of the present invention is to solve the aforementioned problems by providing a continuous hydrogen extraction technology for anhydrous ammonia utilizing a cation exchange reaction.

[0006] Another objective of the present invention is to provide a system capable of minimizing subsequent processes for the production of high-purity and high-pressure hydrogen.

[0007] According to one aspect of the present invention, a reaction cell (10) for use in an ammonia electrolysis reaction is provided, comprising: an anode (100) comprising a first metal; a cathode (200) comprising a second metal; and a separator (300) comprising a cation exchange membrane (310) located between the anode and the cathode.

[0008] In addition, the first metal may include one or more selected from the group consisting of Ru, Co, Ni, Fe, Pt, Ir, Rh, Mo, Re, Ti, and Pd.

[0009] In addition, the anode may include a carrier comprising one or more selected from the group consisting of carbon, Ni, Ti, Cu, Co, Ag, and stainless steel, and a first metal supported on the carrier.

[0010] In addition, the carrier may have one or more shapes selected from the group consisting of foam, mesh, and plate.

[0011] In addition, the second metal may include one or more selected from the group consisting of Pt, Ru, Pd, Co, Ni, Ir, Rh, Mo, Re, Ti, and Fe.

[0012] Additionally, the cathode (200) may include a carrier comprising one or more selected from the group consisting of carbon, Ni, Ti, Cu, Co, Ag, and stainless steel, and the second metal supported on the carrier.

[0013] In addition, the carrier may have one or more shapes selected from the group consisting of foam, mesh, and plate.

[0014] In addition, ammonium ions (NH4) in the cation exchange membrane (310) + ) and protons (H +A cation exchange reaction comprising one or more selected from the group consisting of ) can be performed.

[0015] In addition, hydrogen (H2) can be extracted and produced from the cathode (200) through the exchange reaction of the cations.

[0016] In addition, the electrochemical reaction occurring in the above reaction cell (10) may be performed by one or more reactions selected from the group consisting of reaction formula 1 and reaction formula 2.

[0017] [Reaction Equation 1]

[0018] Cathode: 3NH4 + + 3e - → 3 / 2H2(g) + 3NH3(l)

[0019] Anode: 4NH3(l) → 1 / 2N2(g) + 3NH4 + + 3e -

[0020] Net: NH3→ 1 / 2N2+ 3 / 2H2

[0021] [Reaction Equation 2]

[0022] Cathode: 3H + + 3e - → 3 / 2H2(g)

[0023] Anode: 4NH3(l) → 1 / 2N2(g) + 3NH4 + + 3e -

[0024] Net: NH3→ 1 / 2N2+ 3 / 2H2

[0025] In addition, the above ammonia electrolysis reaction may use anhydrous ammonia.

[0026] Additionally, the reaction cell (10) comprises a first electrolyte in contact with the anode and a second electrolyte in contact with the cathode, wherein the first electrolyte and the second electrolyte each comprise ammonium ions (NH4 +It may include ).

[0027] In addition, the first electrolyte and the second electrolyte may each include one or more selected from the group consisting of NH4F, NH4Cl, NH4Br, NH4I, NH4BF6, NH4NO3, NH4PF6, (NH4)3PO4 and (NH4)2SO4.

[0028] According to another aspect of the present invention, an electrochemical hydrogen extraction system (1) is provided, comprising: a first ammonia tank (20) for storing ammonia; a first mixer (30) for producing a first electrolyte mixture by stirring ammonia supplied from the first ammonia tank with a first electrolyte; a second ammonia tank (40) for storing ammonia; a second mixer (50) for producing a second electrolyte mixture by stirring ammonia supplied from the second ammonia tank with a second electrolyte; and a reaction cell (10) for producing hydrogen (H2) and nitrogen (N2) by receiving the first electrolyte mixture and the second electrolyte mixture and performing an electrolytic reaction.

[0029] Additionally, the reaction cell (10) may include an anode (100) containing a first metal; a cathode (200) containing a second metal; and a separator (300) including a cation exchange membrane (310) located between the anode and the cathode.

[0030] Additionally, the reaction cell (10) may be of a zero-gap type, with no gap between the anode (100) and the separator (300), and no gap between the cathode (200) and the separator (300).

[0031] In addition, the mixture of the first mixer and the second mixer may each contain the first electrolyte and the second electrolyte in an amount of 0.01 to 10 M.

[0032] In addition, the temperature of the mixture of the first mixer and the second mixer may be -33 to 80°C, and the pressure may be 1 to 50 bar, respectively.

[0033] In addition, the first electrolyte and the second electrolyte may each include one or more selected from the group consisting of NH4F, NH4Cl, NH4Br, NH4I, NH4BF6, NH4NO3, NH4PF6, (NH4)3PO4 and (NH4)2SO4.

[0034] Additionally, the electrochemical hydrogen extraction system (1) further includes a first ammonia trap (60) and a second ammonia trap (70), wherein the first ammonia trap (60) receives nitrogen and ammonia from the reaction cell (10) to trap ammonia and separate nitrogen, and the second ammonia trap (70) receives hydrogen and ammonia from the reaction cell (10) to trap ammonia and separate hydrogen.

[0035] Additionally, the electrochemical hydrogen extraction system (1) may further include a chiller (80), and the chiller (80) may receive unreacted ammonia from the reaction cell (10), cool it, and supply the cooled unreacted ammonia to the first mixer (30) and the second mixer (50).

[0036] In addition, the above ammonia may include anhydrous ammonia.

[0037] The present invention can provide a hydrogen production technology based on the electrolysis of anhydrous ammonia through cation exchange.

[0038] In addition, the production of high-purity, high-pressure hydrogen can be achieved with low energy consumption.

[0039] 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.

[0040] Figure 1 shows the electrochemical hydrogen extraction system of the present invention.

[0041] Figure 2 shows a reaction cell of the present invention.

[0042] Figures 3a and 3b show the amount of current generated relative to the applied voltage using Linear Sweep Voltammetry (LSV) related to active metal screening.

[0043] Figures 4a and 4b are Tafel slopes based on the linear scanning potential method of Figures 3a and 3b related to active metal screening, representing the rates of nitrogen and hydrogen evolution reactions, respectively.

[0044] Figure 5 shows 0.1 A / cm² using the constant current experimental method. 2 This is a graph showing the voltage measured by applying a current of (total 2.5 A) for 1 hour each.

[0045] Figure 6 shows 0.1 A / cm² using the constant current experimental method. 2 This is a graph showing the purity of hydrogen, ammonia concentration, and hydrogen pressure while applying a current of (total 2.5 A) for 1 hour each.

[0046] Figure 7 is a graph comparing the hydrogen generation rates of the present invention and the prior art.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Hereinafter, the reaction cell for ammonia electrolysis reaction and the electrochemical hydrogen extraction system including the same according to the present invention 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.

[0053] The present invention provides a reaction cell (10) for use in an ammonia electrolysis reaction comprising: an anode (100) comprising a first metal; a cathode (200) comprising a second metal; and a separator (300) comprising a cation exchange membrane (310) located between the anode and the cathode.

[0054] In addition, the first metal may include one or more selected from the group consisting of Ru, Co, Ni, Fe, Pt, Ir, Rh, Mo, Re, Ti, and Pd.

[0055] In addition, the anode may include a carrier comprising one or more selected from the group consisting of carbon, Ni, Ti, Cu, Co, Ag, and stainless steel, and a first metal supported on the carrier.

[0056] In addition, the carrier may have one or more shapes selected from the group consisting of foam, mesh, and plate.

[0057] In addition, the second metal may include one or more selected from the group consisting of Pt, Ru, Pd, Co, Ni, Ir, Rh, Mo, Re, Ti, and Fe.

[0058] Additionally, the cathode (200) may include a carrier comprising one or more selected from the group consisting of carbon, Ni, Ti, Cu, Co, Ag, and stainless steel, and the second metal supported on the carrier.

[0059] In addition, the carrier may have one or more shapes selected from the group consisting of foam, mesh, and plate.

[0060] In addition, ammonium ions (NH4) in the cation exchange membrane (310) + ) and protons (H + A cation exchange reaction comprising one or more selected from the group consisting of ) can be performed.

[0061] In addition, hydrogen (H2) can be extracted and produced from the cathode (200) through the exchange reaction of the cations.

[0062] In addition, the electrochemical reaction occurring in the above reaction cell (10) may be performed by one or more reactions selected from the group consisting of reaction formula 1 and reaction formula 2.

[0063] [Reaction Equation 1]

[0064] Cathode: 3NH4 + + 3e - → 3 / 2H2(g) + 3NH3(l)

[0065] Anode: 4NH3(l) → 1 / 2N2(g) + 3NH4 + + 3e -

[0066] Net: NH3→ 1 / 2N2+ 3 / 2H2

[0067] [Reaction Equation 2]

[0068] Cathode: 3H + + 3e - → 3 / 2H2(g)

[0069] Anode: 4NH3(l) → 1 / 2N2(g) + 3NH4 + + 3e -

[0070] Net: NH3→ 1 / 2N2+ 3 / 2H2

[0071] In addition, the above ammonia electrolysis reaction may use anhydrous ammonia.

[0072] Additionally, the reaction cell (10) comprises a first electrolyte in contact with the anode and a second electrolyte in contact with the cathode, wherein the first electrolyte and the second electrolyte each comprise ammonium ions (NH4 + It may include ).

[0073] In addition, the first electrolyte and the second electrolyte may each include one or more selected from the group consisting of NH4F, NH4Cl, NH4Br, NH4I, NH4BF6, NH4NO3, NH4PF6, (NH4)3PO4 and (NH4)2SO4.

[0074] According to another aspect of the present invention, an electrochemical hydrogen extraction system (1) is provided, comprising: a first ammonia tank (20) for storing ammonia; a first mixer (30) for producing a first electrolyte mixture by stirring ammonia supplied from the first ammonia tank with a first electrolyte; a second ammonia tank (40) for storing ammonia; a second mixer (50) for producing a second electrolyte mixture by stirring ammonia supplied from the second ammonia tank with a second electrolyte; and a reaction cell (10) for producing hydrogen (H2) and nitrogen (N2) by receiving the first electrolyte mixture and the second electrolyte mixture and performing an electrolytic reaction.

[0075] Additionally, the reaction cell (10) may include an anode (100) containing a first metal; a cathode (200) containing a second metal; and a separator (300) including a cation exchange membrane (310) located between the anode and the cathode.

[0076] Additionally, the reaction cell (10) may be of a zero-gap type, in which there is no gap between the anode (100) and the separator (300), and no gap between the cathode (200) and the separator (300). Unlike MEA, the zero-gap type allows for immediate assembly after the fabrication of the electrode catalyst, making the application of the catalyst-separator simple. In the case of an MEA (Membrane-Electrode Assembly), an additional process of coating the electrode on the separator is added.

[0077] In addition, the mixture of the first mixer and the second mixer may each contain the first electrolyte and the second electrolyte in an amount of 0.01 to 10 M. If the first electrolyte and the second electrolyte are contained in an amount of less than 0.01 M, it is not desirable because it does not provide sufficient electrical conductivity and exhibits a high overpotential, and if it is contained in an amount exceeding 10 M, it becomes slurried beyond the limit value of the solubility of the electrolyte, causing blockage of the piping and irregular supply flow rate during the ammonia supply process, which prevents the smooth and uniform reaction from proceeding, and is therefore not desirable.

[0078] In addition, the temperature of the mixture of the first mixer and the second mixer may be -33 to 80°C, preferably 10°C, and the pressure may be 1 to 50 bar.

[0079] If the above temperature is below -33 ℃, it is undesirable because additional equipment installation is required due to supercooling, and if it exceeds 80 ℃, it is undesirable because additional equipment installation is required due to an increase in reaction pressure. As the temperatures of the first and second mixers are lower, the vapor pressure of ammonia decreases, and the tendency to exist as a liquid becomes stronger, thereby minimizing the ammonia concentration in the gas discharged through the back pressure regulator. Therefore, a reaction temperature of 10 ℃ is desirable.

[0080] If the pressure is less than 1 bar, it is undesirable to maintain a very low temperature (<0 ℃) to liquefy anhydrous ammonia, which leads to increased process difficulty and costs, and if it exceeds 50 bar, it is undesirable to maintain a very low temperature (<0 ℃) to liquefy anhydrous ammonia, which leads to increased process difficulty and costs.

[0081] In addition, the first electrolyte and the second electrolyte may each include one or more selected from the group consisting of NH4F, NH4Cl, NH4Br, NH4I, NH4BF6, NH4NO3, NH4PF6, (NH4)3PO4 and (NH4)2SO4.

[0082] Additionally, the electrochemical hydrogen extraction system (1) further includes a first ammonia trap (60) and a second ammonia trap (70), wherein the first ammonia trap (60) receives nitrogen and ammonia from the reaction cell (10) to trap ammonia and separate nitrogen, and the second ammonia trap (70) receives hydrogen and ammonia from the reaction cell (10) to trap ammonia and separate hydrogen.

[0083] Additionally, the electrochemical hydrogen extraction system (1) may further include a chiller (80), and the chiller (80) may receive unreacted ammonia from the reaction cell (10), cool it, and supply the cooled unreacted ammonia to the first mixer (30) and the second mixer (50).

[0084] In addition, the temperature of the chiller can be maintained at 0℃ or lower.

[0085] In addition, the above ammonia may include anhydrous ammonia.

[0086] In addition, the reaction cell may further include a pressure gauge and a temperature controller (TC). Temperature and pressure can be monitored by installing a pressure gauge at the downstream end of the reaction cell and a TC at the inlets of the positive and negative electrodes.

[0087] In conventional thermochemical ammonia decomposition hydrogen extraction methods, a separation and purification process for unreacted ammonia and nitrogen was essential to produce high-purity hydrogen. Additionally, producing high-pressure hydrogen required inducing the thermal decomposition reaction under high-pressure conditions, which presented a problem due to a decrease in reactivity based on Le Chatelier's principle.

[0088] In addition, in the case of anion exchange type anhydrous ammonia electrolysis technology, which is a method for extracting hydrogen based on anhydrous ammonia through anion exchange reactions rather than cation exchange, NH2 - Electrolysis reactions are induced using ion-containing materials. However, only two materials are commercially available: LiNH2 and NaNH2, which are very expensive. These are flammable substances that pose a fire hazard during storage and exhibit violent explosiveness when reacting with water. Additionally, the electrolytes tend to deteriorate easily during long-term storage. Furthermore, while there is a technology that utilizes synthesized KNH2, this is not suitable for equipping large-capacity hydrogen extraction systems.

[0089] [Anion Exchange Reaction Equation]

[0090] Anode: 6NH2 - (l) → N2(g) + 4NH3(l) + 6e -

[0091] Cathode: 6NH3(l) + 6e - → 3H2(g) + 6NH2 -

[0092] Net Reaction: NH3(l) → 1 / 2N2(g) + 3 / 2H2(g),E= +0.076 V

[0093] The present invention is a continuous hydrogen extraction technology for anhydrous ammonia utilizing a cation exchange reaction.

[0094] In the case of the cation exchange reaction of the present invention, there is a wide variety of commercially available electrolytes available at low prices. Regarding storage, it is non-flammable, allowing for safe storage, and it has very high solubility in anhydrous ammonia, which is advantageous for improving reactivity. This can lead to a reduction in overall process costs.

[0095] In addition, in the electrolysis of anhydrous ammonia through anion exchange, using an electrolyte containing ammonium cations causes a decrease in reactivity by allowing counter-anions such as F, Cl, Br, and I to pass through.

[0096] Conversely, in the case of the electrolysis reaction of anhydrous ammonia through the cation exchange reaction of the present invention, when amide ions are utilized, counter-cations such as Na and Li pass through preferentially, causing a decrease in reaction efficiency.

[0097] In addition, when using a cation exchange membrane, as shown in Equation 2, not only ammonium ions but also protons can be exchanged simultaneously, which can contribute to improving overall reaction efficiency.

[0098] The high-purity and high-pressure hydrogen production of the present invention can minimize subsequent processes.

[0099] In the case of high-purity hydrogen, there is the possibility of minimizing separation and purification and direct linkage, and in the case of high-pressure hydrogen, there is the possibility of direct linkage to subsequent processes, improved fuel cell efficiency when linked to fuel cells, and the elimination of the need for a booster pump compared to conventional 1 atm hydrogen production.

[0100] [Example]

[0101] 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.

[0102] Preparation Example: Active Metal Screening

[0103] Active metals were screened using linear sweep voltammetry (LSV) with carbon paper loaded with Pt, Ru, Pd, Fe, Ni, or Co metals, based on the amount of current generated relative to the applied voltage and the reaction rate of nitrogen and hydrogen generation via the Tafel Slope.

[0104] Figures 3a and 3b show linear sweep voltammetry (LSV) related to active metal screening, and Figures 4a and 4b show tafel slopes based on Figures 3a and 3b related to active metal screening.

[0105] Referring to Figures 3a, 3b, 4a, and 4b, it was confirmed that Ru metal, which has the highest current generation rate relative to the same voltage, exhibits the best activity and fastest nitrogen production rate at the oxidation electrode (anode), while Pt metal exhibits the best activity and fastest hydrogen production rate at the reduction electrode (cathode).

[0106] Example: Electrochemical hydrogen extraction system

[0107] FIG. 1 shows an electrochemical hydrogen extraction system of the present invention, and FIG. 2 shows a reaction cell and reaction equation of the present invention.

[0108] Referring to Fig. 1, anhydrous ammonia is injected into a mixer to stir an electrolyte containing ammonium ions in the range of 0 to 10 M. At this time, since ammonia has the characteristic of rapidly changing pressure depending on temperature, the temperature of the transfer path connecting the mixer and the reactor must be equal to the reaction temperature to minimize pressure changes caused by temperature fluctuations during the transfer of the reactants. The chiller used is maintained at 0°C or lower so that unreacted ammonia can be concentrated back into the mixer.

[0109] Referring to FIG. 2, the reaction cell of the present invention supplies electricity through a current collector plate and supplies anhydrous ammonia through a separator plate, and induces a reaction by positioning a positive electrode-separator (cation exchange membrane)-negative electrode between the positive and negative separator plates. The reaction proceeded in a zero-gap form rather than a Membrane-Electrode Assembly (MEA) form.

[0110] [Test Example]

[0111] Test Example 1: Analysis of the electrolysis reaction of anhydrous ammonia (constant current test method)

[0112] For the anhydrous ammonia electrolysis reaction, experiments were conducted under conditions of 10 ℃, 6.1 atm, and 5 M NH4Br electrolyte, and the reaction cell was 25 cm 2 The process was conducted using the constant current experimental method at 0.1 A / cm 2 (Total 2.5 A) The voltage was measured by applying current for 1 hour each.

[0113] Figure 5 shows 0.1 A / cm² using the constant current experimental method. 2 This is a graph showing the voltage measured by applying a current of (total 2.5 A) for 1 hour each, and Figure 6 shows 0.1 A / cm² using the constant current experimental method. 2 Figure 7 is a graph showing the hydrogen purity, ammonia concentration, and hydrogen pressure measured while applying a current of (total 2.5 A) for one hour each, and a graph comparing the hydrogen generation rate of the present invention and the prior art.

[0114] For reference, the source of the paper listed in Fig. 7 is as follows.

[0115] 1. Kang, S., Cha, J., Jo, YS, Lee, YJ, Sohn, H., Kim, Y., Song, C.K., Kim, Y., Lim, D.H., Park, J., and Yoon, C.W. (2023). Heteroepitaxial Growth of B5-Site-Rich Ru Nanoparticles Guided by Hexagonal Boron Nitride for Low-Temperature Ammonia Dehydrogenation. Adv. Mater.35, 2203364

[0116] 2. Lim, D.-K., Plymill, A.B., Paik, H., Qian, X., Zecevic, S., Chisholm, C.R., and Haile, S.M. (2020). Solid acid electrochemical cell for the production of hydrogen from ammonia. Joule4, 2338-2347.

[0117] 3. Tabassum, H., Mukherjee, S., Chen, J., Holiharimanana, D., Karakalos, S., Yang, X., Hwang, S., Zhang, T., Lu, B., and Chen, M. (2022). Hydrogen generation via ammonia decomposition on highly efficient and stable Ru-free catalysts: approaching complete conversion at 450° C. Energy Environ. Sci.15, 4190-4200.

[0118] 4. Yamazaki, K., Matsumoto, M., Ishikawa, M., and Sato, A. (2023). NH3 decomposition over Ru / CeO2-PrOx catalyst under high space velocity conditions for an on-site H2 fueling station. Appl. Catal. B: Environ.325, 122352.

[0119] 5. Yin, S., Xu, B., Wang, S., Ng, C., and Au, C. (2004). Magnesia-carbon nanotubes (MgO-CNTs) nanocomposite: Novel support of Ru catalyst for the generation of CO x-free hydrogen from ammonia. Catal. Letters96, 113-116.

[0120] 6. Xiong, P., Xu, Z., Wu, T.-S., Yang, T., Lei, Q., Li, J., Li, G., Yang, M., Soo, Y.-L., and Bennett, R.D. (2024). Synthesis of core@ shell catalysts guided by Tammann temperature. Nat. Commun.15, 420.

[0121] 7. Huang, D.-C., Jiang, C.-H., Liu, F.-J., Cheng, Y.-C., Chen, Y.-C., and Hsueh, K.-L. (2013). Preparation of Ru-Cs catalyst and its application on hydrogen production by ammonia decomposition. Int. J. Hydrog. Energy38, 3233-3240.

[0122] 8. Yin, S.-F., Xu, B.-Q., Ng, C.-F., and Au, C.-T. (2004). Nano Ru / CNTs: a highly active and stable catalyst for the generation of COx-free hydrogen in ammonia decomposition. Appl. Catal. B: Environ.48, 237-241.

[0123] 9. Fang, H., Wu, S., Ayvali, T., Zheng, J., Fellowes, J., Ho, P.-L., Leung, K.C., Large, A., Held, G., and Kato, R. (2023). Dispersed surface Ru ensembles on MgO (111) for catalytic ammonia decomposition. Nat. Commun.14, 647.

[0124] Referring to Figures 5 to 7, the pressure of the generated hydrogen was >5.5 bar (g), the purity of the hydrogen was >99.9997%, and the hydrogen production efficiency relative to the applied current was an average of >95% or higher, with an hourly hydrogen production volume of approximately 1.114 L. Through this, it was confirmed that hydrogen with high purity and high pressure has advantages such as ease of linkage with subsequent processes and minimization of separation and purification processes.

[0125] Furthermore, when comparing the hydrogen production per unit weight, it is 0.1 A / cm² at a very low temperature compared to conventional pyrolysis technology. 2 At an equivalent level, 0.3 A / cm 2 Significantly higher hydrogen production was recorded above. This confirmed that thermochemical hydrogen production technology can be completely replaced through technological development.

[0126] 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

1. An anode (anode, 100) containing a first metal; A cathode (200) comprising a second metal; and A separator (300) including a cation exchange membrane (310) located between the anode and the cathode; A reaction cell (10) for use in an ammonia electrolysis reaction containing.

2. In Paragraph 1, A reaction cell characterized in that the first metal comprises one or more selected from the group consisting of Ru, Co, Ni, Fe, Pt, Ir, Rh, Mo, Re, Ti, and Pd.

3. In Paragraph 1, A reaction cell characterized by comprising an anode, a carrier comprising one or more selected from the group consisting of carbon, Ni, Ti, Cu, Co, Ag, and stainless steel, and a first metal supported on said carrier.

4. In Paragraph 1, A reaction cell characterized in that the second metal comprises one or more selected from the group consisting of Pt, Ru, Pd, Co, Ni, Ir, Rh, Mo, Re, Ti, and Fe.

5. In Paragraph 1, A reaction cell characterized in that the above-described cathode (200) comprises a carrier comprising one or more selected from the group consisting of carbon, Ni, Ti, Cu, Co, Ag, and stainless steel, and a second metal supported on the carrier.

6. In Paragraph 1, Ammonium ions (NH4) in the cation exchange membrane (310) above + ) and protons (H + A reaction cell characterized by performing a cation exchange reaction comprising one or more selected from the group consisting of ).

7. In Paragraph 6, A reaction cell characterized in that hydrogen (H2) is extracted and produced at the cathode (200) through the exchange reaction of the cations.

8. In Paragraph 1, A reaction cell characterized in that the electrochemical reaction occurring in the above reaction cell (10) is performed by one or more reactions selected from the group consisting of reaction formula 1 and reaction formula 2. [Reaction Equation 1] Cathode: 3NH4 + + 3e - → 3 / 2H2(g) + 3NH3(l) Anode: 4NH3(l) → 1 / 2N2(g) + 3NH4 + + 3e - Net: NH3→ 1 / 2N2+ 3 / 2H2 [Reaction Equation 2] Cathode: 3H + + 3e - → 3 / 2H2(g) Anode: 4NH3(l) → 1 / 2N2(g) + 3NH4 + + 3e - Net: NH3→ 1 / 2N2+ 3 / 2H2 9. In Paragraph 1, A reaction cell characterized by the use of anhydrous ammonia in the above ammonia electrolysis reaction.

10. In Paragraph 1, The above reaction cell (10) includes a first electrolyte in contact with the anode and a second electrolyte in contact with the cathode, and The first electrolyte and the second electrolyte are each ammonium ions (NH4 + A reaction cell characterized by including ).

11. In Paragraph 10, A reaction cell characterized in that the first electrolyte and the second electrolyte each comprise one or more selected from the group consisting of NH4F, NH4Cl, NH4Br, NH4I, NH4BF6, NH4NO3, NH4PF6, (NH4)3PO4 and (NH4)2SO4.

12. A first ammonia tank (20) for storing ammonia; A first mixer (30) that produces a first electrolyte mixture by stirring the ammonia supplied from the first ammonia tank with the first electrolyte; A second ammonia tank (40) for storing ammonia; A second mixer (50) that produces a second electrolyte mixture by stirring the ammonia supplied from the second ammonia tank with the second electrolyte; and A reaction cell (10) that receives the first electrolyte mixture and the second electrolyte mixture and performs an electrolysis reaction to produce hydrogen (H2) and nitrogen (N2); Electrochemical hydrogen extraction system (1) including 13. In Paragraph 12, The above reaction cell (10) An anode (100) containing a first metal; A cathode (200) comprising a second metal; and An electrochemical hydrogen extraction system characterized by including a separator (300) comprising a cation exchange membrane (310) located between the anode and the cathode.

14. In Paragraph 13, The electrochemical hydrogen extraction system is characterized in that the reaction cell (10) is of the zero-gap type, with no gap between the anode (100) and the separator (300) and no gap between the cathode (200) and the separator (300).

15. In Paragraph 12, An electrochemical hydrogen extraction system characterized in that the mixture of the first mixer and the second mixer each contains the first electrolyte and the second electrolyte in an amount of 0.01 to 10 M.

16. In Paragraph 12, An electrochemical hydrogen extraction system characterized in that the temperature of the mixture of the first mixer and the second mixer is -33 to 80°C, and the pressure is 1 to 50 bar, respectively.

17. In Paragraph 12, An electrochemical hydrogen extraction system characterized in that the first electrolyte and the second electrolyte each comprise one or more selected from the group consisting of NH4F, NH4Cl, NH4Br, NH4I, NH4BF6, NH4NO3, NH4PF6, (NH4)3PO4 and (NH4)2SO4.

18. In Paragraph 12, The above electrochemical hydrogen extraction system further includes a first ammonia trap (60) and a second ammonia trap (70), and The first ammonia trap (60) receives nitrogen and ammonia from the reaction cell (10), traps the ammonia, and separates the nitrogen. An electrochemical hydrogen extraction system characterized in that the second ammonia trap (70) receives hydrogen and ammonia from the reaction cell (10), traps the ammonia, and separates the hydrogen.

19. In Paragraph 12, The above electrochemical hydrogen extraction system (1) further includes a chiller (80), and An electrochemical hydrogen extraction system characterized in that the chiller (80) receives unreacted ammonia from the reaction cell (10), cools it, and supplies the cooled unreacted ammonia to the first mixer (30) and the second mixer (50).

20. In Paragraph 12, An electrochemical hydrogen extraction system characterized in that the above ammonia includes anhydrous ammonia.

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