Method for preparing catalyst for oxygen evolution reaction in water electrolysis cell, and water electrolysis cell membrane-electrode assembly and water electrolysis cell, which comprise catalyst prepared using same

Abstract

The present disclosure relates to a method for preparing a catalyst for an oxygen evolution reaction in a water electrolysis cell, and a water electrolysis cell membrane-electrode assembly and a water electrolysis cell, which comprise the catalyst prepared using same, and the method for preparing a catalyst for an oxygen evolution reaction in a water electrolysis cell comprises preparing a plurality of noble metal oxide seeds, and preparing a noble metal oxide aggregate by using the plurality of noble metal oxide seeds, thereby increasing the surface area thereof by means of pores between noble metal oxide particles, and thus performance and durability can be improved.

Description

Method for producing a catalyst for oxygen generation reaction in a water electrolysis cell, and a membrane-electrode assembly and water electrolysis cell including a catalyst produced therefrom

[0001] The present disclosure relates to a method for producing a catalyst for an oxygen evolution reaction in a water electrolysis cell, and a membrane-electrode assembly and a water electrolysis cell including the catalyst produced therefrom, and more particularly, to a method for producing a catalyst for an oxygen evolution reaction in a water electrolysis cell, in which a plurality of noble metal oxide seeds are produced, and a noble metal oxide aggregate is produced using the plurality of noble metal oxide seeds, thereby increasing a surface area due to pores between the noble metal oxide particles and improving performance and durability, and a membrane-electrode assembly and a water electrolysis cell including the catalyst produced therefrom.

[0002] This disclosure relates to the results of a project (Project ID: 20022451) carried out with the support of the Materials and Components Technology Development Project of the Ministry of Trade, Industry and Energy and the Korea Institute for Advancement of Technology (KEIT).

[0003] Recent energy demands and environmental concerns demand sustainable supply, environmental friendliness, and high efficiency, and among these, hydrogen is attracting attention as a raw material for renewable energy.

[0004] Hydrogen energy is classified into gray, blue, and green hydrogen depending on the production method. Gray and blue hydrogen have the problem that carbon dioxide is generated during the production process or cannot be completely removed because they use fossil fuels.

[0005] Green hydrogen refers to hydrogen produced through the electrolysis of infinite water. Because the hydrogen production process produces no carbon dioxide, it is attracting attention as the ultimate eco-friendly energy source. Water electrolysis technology is necessary to produce green hydrogen.

[0006] Electrolysis is an electrochemical process that generates hydrogen and oxygen by electrolyzing water and transporting ions across a membrane. Electrolysis can be divided into two half-cell reactions: the hydrogen evolution reaction (HER), which occurs at the reduction electrode, and the oxygen evolution reaction (OER), which occurs at the oxidation electrode.

[0007] This is a technology related to a catalyst for water electrolysis, particularly a catalyst for an oxygen evolution electrode of a polymer electrolyte membrane (PEM) water electrolysis. Conventionally, iridium black and iridium oxide powder have been used as catalysts for oxygen evolution reactions in PEM water electrolysis oxygen evolution electrodes, but improvements are required for their low dispersibility, low electrical conductivity, and instability.

[0008] According to one embodiment, a method for producing a catalyst for an oxygen evolution reaction in an electrolysis cell is provided, wherein a plurality of precious metal oxide seeds are produced, and a precious metal oxide aggregate is produced using the plurality of precious metal oxide seeds, thereby increasing the surface area due to pores between the precious metal oxide particles and improving performance and durability.

[0009] According to another embodiment, a membrane-electrode assembly for an electrolysis cell and an electrolysis cell are provided, including a catalyst for an oxygen evolution reaction of an electrolysis cell manufactured according to the method for manufacturing a catalyst for an oxygen evolution reaction of the electrolysis cell.

[0010] A method for manufacturing a catalyst for an oxygen generation reaction of a water electrolysis cell according to one embodiment includes forming a plurality of noble metal oxide seeds by hydrothermally reacting a precursor of a noble metal oxide, injecting a solution containing the plurality of noble metal oxide seeds into a mold to aggregate the plurality of noble metal oxide seeds, and performing a heat treatment on the aggregated plurality of noble metal oxide seeds to form a noble metal oxide aggregate.

[0011] The precursor of the above noble metal oxide may include iridium (Ir) chloride, iridium acetate, iridium amine, iridium sulfide, or a combination thereof.

[0012] The precursor of the above noble metal oxide may further include a chloride, acetate, amine, sulfide, or combination thereof of a noble metal, including Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof.

[0013] The above-mentioned hydrothermal reaction can be performed at a temperature in the range of 60°C to 120°C for 0.5 to 3 hours.

[0014] The diameter of the above precious metal oxide seed may be in the range of 2 nm to 50 nm.

[0015] The above mold may be an anodic aluminum oxide membrane (AAO membrane), a cellulose membrane, a polycarbonate membrane, or a nylon membrane including a substrate and a plurality of pores penetrating the substrate in the thickness direction.

[0016] The diameter of the pores of the above mold may be in the range of 10 nm to 200 nm.

[0017] The above plurality of precious metal oxide seeds are laminated in a plurality of layers within the pores of the mold, and each of the layers may include a plurality of the above precious metal oxide seeds.

[0018] After being injected into the mold, a vacuum adsorption process is further performed, and the vacuum adsorption process can be performed for 10 to 100 minutes under a pressure within the range of 5 kPa to 20 kPa.

[0019] The above heat treatment can be performed at a temperature in the range of 350°C to 600°C for 0.5 to 4 hours.

[0020] The above noble metal oxide aggregate may be in the shape of a nanowire.

[0021] According to another embodiment, a membrane-electrode assembly for a water electrolysis cell comprises: a polymer electrolyte membrane; an oxygen generation electrode positioned on one side of the polymer electrolyte membrane and including a catalyst for an oxygen evolution reaction; and a hydrogen generation electrode positioned on the other side of the polymer electrolyte membrane; wherein the oxygen evolution reaction catalyst may include a noble metal oxide aggregate in which a plurality of noble metal oxide particles including a noble metal oxide are aggregated in a nanowire shape.

[0022] The above noble metal oxide complex has a BET surface area of ​​50 m 2 / g can be more than that.

[0023] The above noble metal oxide particles are laminated into a plurality of layers along the longitudinal direction of the noble metal oxide aggregate, and each of the layers may include a plurality of the above noble metal oxide particles.

[0024] The diameter of the noble metal oxide aggregate may be in the range of 10 nm to 200 nm, and the length of the noble metal oxide aggregate may be in the range of 150 nm to 800 nm.

[0025] The above noble metal oxide is IrO x(where x is an integer from 1 to 3), IrMO x (wherein M includes Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof, and x is an integer from 1 to 3) or a combination thereof.

[0026] The above oxygen generation electrode further includes an ion conductor, and the oxygen generation electrode may include the oxygen generation reaction catalyst in a range of 70 wt% to 95 wt% based on the total weight of the oxygen generation electrode.

[0027] The above hydrogen generation electrode may include a carbon-based carrier and a hydrogen generation catalyst including active particles containing a precious metal and supported on the carbon-based carrier.

[0028] The polymer electrolyte membrane may include a porous support including a plurality of pores, and an ion conductor filling the pores of the porous support.

[0029] According to another embodiment, a hydroelectric cell comprises the membrane-electrode assembly.

[0030] A method for producing a catalyst for an oxygen generation reaction of a water electrolysis cell according to one embodiment comprises producing a plurality of precious metal oxide seeds and producing a precious metal oxide aggregate using the plurality of precious metal oxide seeds, whereby the surface area is increased due to pores between the precious metal oxide particles, thereby improving performance and durability.

[0031] Figure 1 is a schematic diagram showing the manufacturing process of a catalyst for oxygen generation reaction in a water electrolysis cell according to one embodiment.

[0032] FIG. 2 is a schematic diagram showing a membrane-electrode assembly (MEA) for a water electrolysis cell according to one embodiment.

[0033] Figure 3 is a scanning electron microscope (SEM) photograph of the oxygen evolution reaction catalyst of the electrolysis cell manufactured in Example 1.

[0034] Figure 4 is a transmission electron microscope (TEM) photograph of a catalyst for oxygen evolution reaction in a water electrolysis cell manufactured in Example 2.

[0035] Figure 5 is a graph showing the results of measuring the BET specific surface area of ​​the oxygen generation reaction catalyst of the electrolysis cell manufactured in Examples 1 to 2 and Comparative Examples.

[0036] Figure 6 is a graph showing the results of evaluating the IV characteristics of a membrane-electrode assembly including an oxygen evolution reaction catalyst of a water electrolysis cell manufactured in Examples 1 to 2 and a comparative example.

[0037] Hereinafter, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0038] As used herein, “combination thereof” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0039] It should be understood that the terms “include,” “comprising,” or “having” used in this specification are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0040] In this specification, terms are used solely to distinguish one component from another. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0041]

[0042] 1. Method for manufacturing a catalyst for oxygen generation reaction in a water electrolysis cell

[0043] A method for manufacturing a catalyst for an oxygen generation reaction of a water electrolysis cell according to one embodiment includes forming a plurality of noble metal oxide seeds by hydrothermally reacting a precursor of a noble metal oxide, injecting a solution containing the plurality of noble metal oxide seeds into a mold to aggregate the plurality of noble metal oxide seeds, and performing a heat treatment on the aggregated plurality of noble metal oxide seeds to form a noble metal oxide aggregate.

[0044] The method for manufacturing an oxygen generation reaction catalyst of the above-mentioned electrolytic cell forms a plurality of precious metal oxide seeds using a precursor of a precious metal oxide, and by injecting the plurality of seeds into a mold and agglomerating them, the surface area is increased due to pores between the particles of the precious metal oxide compared to the conventional method of directly injecting a precursor of a precious metal oxide into a mold, thereby improving performance and durability.

[0045] The precursor of the above precious metal oxide refers to a material in a previous stage of the precious metal oxide, which is the final product.

[0046] The precursor of the above noble metal oxide may include iridium (Ir) chloride, iridium acetate, iridium amine, iridium sulfide, or a combination thereof.

[0047] According to one embodiment, the precursor of the noble metal oxide may be iridium (Ir) chloride, for example, IrCl4.

[0048] The precursor of the above noble metal oxide may further include a chloride, acetate, amine, sulfide, or combination thereof of a noble metal, including Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof.

[0049] The precursor of the above noble metal oxide may include only the iridium (Ir) chloride, iridium acetate, iridium aminide, iridium sulfide, or a combination thereof, or may further include a chloride, acetate, aminide, sulfide, or a combination thereof of a noble metal including Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof together with the iridium (Ir) chloride, iridium acetate, iridium aminide, iridium sulfide, or a combination thereof.

[0050] In another embodiment, the precursor of the noble metal oxide may be a mixture of iridium (Ir) chloride and a chloride of a noble metal including Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof, for example, a mixture of IrCl4 and SnCl4.

[0051] When the precursor of the above noble metal oxide is a mixture of iridium chloride and a chloride of a noble metal including Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof, the final product may be an iridium alloy oxide.

[0052] A hydrothermal reaction may also be carried out by further including a weak reducing agent together with the precursor of the above noble metal oxide.

[0053] The above reducing agent may include formaldehyde, formic acid, oxalic acid, ascorbic acid, citric acid, urea, ethylenediamine, hexamethylenetetramine, or a combination thereof.

[0054] The above-mentioned weak reducing agent may be included within a predetermined range relative to 100 parts by weight of the precursor of the noble metal oxide. 100 parts by weight of the precursor of the noble metal oxide refers to the weight of one type of the noble metal oxide precursor when included, and refers to the total weight of the mixed precursors of the noble metal oxide when two or more types of the noble metal oxide precursors are mixed. For example, when the precursor of the noble metal oxide includes iridium chloride and tin chloride, it refers to the weight part of the weak reducing agent when the total weight of the iridium chloride and tin chloride is assumed to be 100 parts by weight.

[0055] For example, the lower limit of the weak reducing agent relative to 100 parts by weight of the precursor of the noble metal oxide may be about 100 parts by weight, 120 parts by weight, 140 parts by weight, 160 parts by weight, 180 parts by weight, 200 parts by weight, 220 parts by weight, 240 parts by weight, 260 parts by weight, 280 parts by weight, or 300 parts by weight, and the upper limit may be about 500 parts by weight, 480 parts by weight, 460 parts by weight, 440 parts by weight, 420 parts by weight, 400 parts by weight, 380 parts by weight, 360 parts by weight, 340 parts by weight, 320 parts by weight, or 300 parts by weight.

[0056] The above reducing agent may have a range of more than or exceeding any one of the lower limits described above, or less than or equal to any one of the upper limits described above, or more than or exceeding any one of the lower limits described above, or less than or equal to any one of the upper limits described above, relative to 100 parts by weight of the precursor of the precious metal oxide.

[0057] The precursor and / or reducing agent of the above noble metal oxide can be mixed in an aqueous solution containing distilled water and subjected to a hydrothermal reaction to form a plurality of noble metal oxide seeds.

[0058] As is well known, the above-mentioned hydrothermal reaction is one of the liquid synthesis methods, which means synthesizing a substance using water or an aqueous solution under high temperature and high pressure.

[0059] The temperature and time of the above hydrothermal reaction can be appropriately controlled depending on the size of the seed. For example, the hydrothermal reaction can be performed at a temperature within a predetermined range for a predetermined time.

[0060] For example, the lower limit of the temperature of the above-described hydrothermal reaction may be about 60°C, 65°C, 70°C, 75°C, or 80°C, and the upper limit may be about 120°C, 110°C, 100°C, 90°C, or 80°C.

[0061] Additionally, the lower limit of the time of the above-described series reaction may be about 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, or 1 hour, and the upper limit may be about 3 hours, 2.5 hours, 2 hours, 1.5 hours, or 1 hour.

[0062] The temperature and time of the above-described series reaction may each have a range that is greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0063] The above precious metal oxide seed refers to a material in a previous stage of the final product, the precious metal oxide particle.

[0064] The precursor of the above noble metal oxide can form a plurality of noble metal oxide seeds having a diameter within a predetermined range according to a hydrothermal reaction. A specific method for measuring the diameter of the above noble metal oxide seeds was to photograph the noble metal oxide seeds using a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0065] The lower limit of the diameter of the above noble metal oxide seed may be about 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm or 10 nm, and the upper limit may be about 50 nm, 45 nm, 40 nm, 35 nm, 30 nm, 25 nm, 20 nm, 15 nm or 10 nm.

[0066] The diameter of the above precious metal oxide seed may be greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above, or less than or equal to any one of the upper limits described above.

[0067] Since the above precious metal oxide seeds have a diameter within a predetermined range, pores between the seeds can be more effectively secured, and the surface area can be increased due to the pores between the seeds, thereby improving performance and durability.

[0068] A solution containing a plurality of oxide seeds manufactured as described above can be injected into a mold.

[0069] Before pouring the above solution into the mold, a weak reducing agent may be further added to the solution. By further adding the weak reducing agent, the agglomeration of the precious metal oxide seeds and the bonding between the agglomerated particles can be strengthened.

[0070] The specific types of the above reducing agent are as described above.

[0071] The above reducing agent may be further added in an amount within a predetermined range relative to 100 parts by weight of the precursor of the noble metal oxide. The meaning of 100 parts by weight of the precursor of the noble metal oxide is as described above.

[0072] For example, the lower limit of the content of the above-mentioned reducing agent may be about 30 parts by weight, 35 parts by weight, 40 parts by weight, 45 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, 80 parts by weight, 90 parts by weight, or 100 parts by weight, and the upper limit may be about 300 parts by weight, 280 parts by weight, 260 parts by weight, 240 parts by weight, 220 parts by weight, 200 parts by weight, 180 parts by weight, 160 parts by weight, 140 parts by weight, 120 parts by weight, or 100 parts by weight.

[0073] The above reducing agent may have a range of more than or exceeding any one of the lower limits described above, less than or equal to any one of the upper limits described above, or more than or exceeding any one of the lower limits described above, or less than or equal to any one of the upper limits described above, relative to a total of 100 parts by weight of the plurality of precious metal oxide seeds.

[0074] The above mold is not limited in type as long as it can form a noble metal oxide aggregate. The term noble metal oxide aggregate refers to something produced from a single pore of the mold. It should be understood that since each pore in the mold is spaced a certain distance apart, the noble metal oxide aggregate produced from each pore does not aggregate and become a single unit. The noble metal oxide aggregate may be in the shape of a nanowire, as described below.

[0075] The mold may be an anodic aluminum oxide (AAO) membrane, a cellulose membrane, a polycarbonate membrane, or a nylon membrane, which includes a substrate and a plurality of pores penetrating the substrate in the thickness direction. For example, the nanowire shape refers to a shape in which noble metal oxide particles are aggregated in a lengthwise direction so that the aspect ratio, which is the ratio of the length to the diameter, is very large. Therefore, it is different from a shape in which noble metal oxide particles are aggregated to have mesopores, or a mesoporous structure in which a plurality of nanowires or nanorods are aggregated and integrated to have mesopores, and the mold does not include something that can form a mesoporous structure. For example, there is mesoporous silica, which is not included in the mold.

[0076] Fig. 1 is a schematic diagram illustrating the manufacturing process of the oxygen evolution reaction catalyst of the above-described electrolysis cell for easy understanding. As illustrated in Fig. 1, the mold may include multiple pores. In Fig. 1, only seven pores are illustrated, but this is only for convenience in indicating that multiple pores are included, and does not indicate the lower and upper limits of the number of pores. The number of pores may be adjusted as needed.

[0077] The diameter of the above pores can be within a predetermined range. The size of the nanowire diameter can be controlled depending on the diameter of the pores. The diameter of the pores was measured by photographing the mold using a scanning electron microscope (SEM).

[0078] The lower limit of the diameter of the pores may be about 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm, and the upper limit of the diameter may be about 200 nm, 180 nm, 160 nm, 140 nm, 120 nm, 100 nm, 80 nm, or 60 nm. The diameter of the pores may be more than or exceeding any one of the lower limits described above; less than or equal to any one of the upper limits described above; or more than or exceeding any one of the lower limits described above and less than or equal to any one of the upper limits described above. By controlling the size of the pores to be within the above-described range, a plurality of noble metal oxide seeds can be laminated in a plurality of layers within the pores of the mold, and each of the layers can contain a plurality of noble metal oxide seeds, thereby increasing the surface area and providing an oxygen evolution reaction catalyst with improved performance and durability.

[0079] As described above, when a solution containing a plurality of noble metal oxide seeds is injected into a mold, the plurality of noble metal oxide seeds are laminated in a plurality of layers within the pores of the mold, and each of the layers may contain a plurality of noble metal oxide seeds.

[0080] As illustrated in Fig. 1, it can be seen that a plurality of precious metal oxide seeds injected into the mold are stacked in a plurality of layers, and each of the layers can include a plurality of the precious metal oxide seeds. Although the formation of a plurality of layers when injected into the mold is not illustrated, according to the right side of Fig. 1, a total of eight layers can be formed, and about seven precious metal oxide seeds can exist in each layer. However, Fig. 1 is an illustration to make it easy to understand this manufacturing process, and it is not necessarily the case that eight layers are formed or that seven precious metal oxide seeds are necessarily present in each layer.

[0081] By first forming a plurality of noble metal oxide seeds and stacking the plurality of noble metal oxide seeds to form a plurality of layers within a mold and including a plurality of noble metal oxide seeds in each layer, the surface area of ​​the noble metal oxide aggregate produced is increased due to pores existing between the noble metal oxide seeds, and thus the performance and durability of the catalyst can be improved.

[0082] After being injected into the above mold, a vacuum adsorption process can be further performed.

[0083] The above vacuum adsorption process refers to the process of adsorbing a substance by creating a vacuum state by lowering the air pressure.

[0084] The above vacuum adsorption can be performed by appropriately adjusting the time and pressure as needed. In one embodiment, the time and pressure of the vacuum adsorption can be within a predetermined range.

[0085] For example, the lower limit of the time may be about 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, or 40 minutes, and the upper limit may be about 100 minutes, 90 minutes, 80 minutes, 70 minutes, 60 minutes, 50 minutes, or 40 minutes. The lower limit of the pressure may be about 5 kPa, 6 kPa, 7 kPa, 8 kPa, 9 kPa, or 10 kPa, and the upper limit may be about 20 kPa, 18 kPa, 16 kPa, 14 kPa, 12 kPa, or 10 kPa. The time and pressure are each equal to or greater than any one of the lower limits described above; or equal to or less than any one of the upper limits described above; Or it may have a range that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0086] The solution subjected to the above vacuum adsorption process can be subjected to a hydrothermal reaction. Through the hydrothermal reaction, a plurality of noble metal oxide particles can be aggregated through interactions between the plurality of noble metal oxide seeds and the weak reducing agent, and the bonding between the seeds can be strengthened.

[0087] The temperature and time of the above-described series reaction are as described above.

[0088] A plurality of noble metal oxide seeds can be aggregated according to the above vacuum adsorption and hydrothermal reaction, and a heat treatment can be performed on the aggregated plurality of noble metal oxide seeds to form a noble metal oxide aggregate.

[0089] The above noble metal oxide aggregate may be composed of a plurality of noble metal oxide particles aggregated together. The noble metal oxide particles refer to a final product obtained after performing a heat treatment process on the noble metal oxide seed. At this time, the plurality of noble metal oxide particles aggregate to such an extent that pores may exist between the noble metal oxide particles, and thus the noble metal oxide aggregate may have pores between the noble metal oxide particles.

[0090] The above heat treatment can be performed at a temperature and time within a predetermined range.

[0091] For example, the lower limit of the temperature of the heat treatment may be about 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, or 450°C, and the upper limit may be about 600°C, 590°C, 580°C, 570°C, 560°C, 550°C, 540°C, 530°C, 520°C, 510°C, 500°C, 490°C, 480°C, 470°C, 460°C, or 450°C.

[0092] In addition, the lower limit of the time of the heat treatment may be about 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1 hour, 1.5 hours, or 2 hours, and the upper limit may be about 4 hours, 3.8 hours, 3.6 hours, 3.4 hours, 3.2 hours, 3 hours, 2.9 hours, 2.8 hours, 2.7 hours, 2.6 hours, 2.5 hours, 2.4 hours, 2.3 hours, 2.2 hours, 2.1 hours, or 2 hours.

[0093] The temperature and time of the heat treatment may each have a range of more than or exceeding any one of the lower limits described above; less than or equal to any one of the upper limits described above; or more than or exceeding any one of the lower limits described above, or less than or equal to any one of the upper limits described above.

[0094] After the above heat treatment process, the mold can be removed.

[0095] The above mold can be removed by a known method depending on the type of mold.

[0096] For example, the mold can be removed using an alkaline solution or a heat treatment process. The alkaline solution can be, for example, sodium hydroxide (NaOH).

[0097] The noble metal oxide aggregate formed according to the above manufacturing process is illustrated on the far right of Fig. 1.

[0098] The noble metal oxide aggregate formed by the above method may have a nanowire shape. The noble metal oxide aggregate formed by the above method may be plural in number. As illustrated in Fig. 1, there may be plural noble metal oxide aggregates manufactured by the above method on the far right. Although only a portion of the noble metal oxide aggregate finally manufactured is illustrated on the far right of Fig. 1, when the noble metal oxide aggregate is manufactured using the mold of Fig. 1, since a total of seven pores exist, a total of seven noble metal oxide aggregates may be formed.

[0099] These noble metal oxide assemblies in the shape of multiple nanowires are not formed as a single, integrated form of multiple nanowires or nanorods, as in a mesoporous structure, but may exist as dispersed entities. For example, a template that can be used to manufacture a noble metal oxide assemblies with a mesoporous structure of 2 nm to 50 nm in size has a maximum pore size of approximately 20 nm, typically approximately 12 nm. In this case, because the pore size of the template is small, noble metal oxide seeds cannot be injected into the pores, and a precursor must be used. Furthermore, in order to manufacture a noble metal oxide assemblies with a mesoporous structure using such a template and then split them into nanowire shapes, a physical external force such as high pressure is required. However, splitting them into nanowire shapes while maintaining their shape is virtually impossible, except in the case of carbon. Therefore, although it is possible to manufacture a noble metal oxide assemblies with a mesoporous structure using such a template, it is not possible to manufacture noble metal oxide assemblies in the shape of multiple nanowires.

[0100] Accordingly, a plurality of noble metal oxide aggregates can be dispersed between a carrier or an ion conductor to better form a three-phase interface. In addition, the noble metal oxide aggregates manufactured according to the above method can improve performance by increasing the number of reactive lattice planes due to the bumpy structure formed from the aggregated individual noble metal oxide particles.

[0101] Since a plurality of noble metal oxide aggregates manufactured according to a method for manufacturing an oxygen evolution reaction catalyst of a water electrolysis cell according to one embodiment exist in individual forms, electrode manufacturing and coating can be made easier than in a form in which a plurality of nanowire shapes are aggregated and integrated into a mesoporous structure.

[0102] According to a method for manufacturing a catalyst for an oxygen generation reaction of a water electrolysis cell according to one embodiment, a noble metal oxide aggregate manufactured has a nanowire shape, so that its surface area increases, thereby improving performance and durability.

[0103]

[0104] 2. Membrane-electrode assembly for electrolysis cell

[0105] According to another embodiment, a membrane-electrode assembly for a water electrolysis cell comprises: a polymer electrolyte membrane; an oxygen evolution electrode positioned on one side of the polymer electrolyte membrane and including a catalyst for an oxygen evolution reaction; and a hydrogen evolution electrode positioned on the other side of the polymer electrolyte membrane.

[0106] The membrane-electrode assembly for the above-described electrolysis cell is illustrated in FIG. 2. The membrane-electrode assembly (100) for the electrolysis cell according to FIG. 2 includes a polymer electrolyte membrane (30); an oxygen generation electrode (10) positioned on one side of the polymer electrolyte membrane; and a hydrogen generation electrode (20) positioned on the other side of the polymer electrolyte membrane.

[0107] Hereinafter, the oxygen generation electrode, the hydrogen generation electrode, and the polymer electrolyte membrane will be described in detail.

[0108] The above oxygen evolution electrode refers to an electrode where an oxygen evolution reaction (OER) occurs, and the above hydrogen evolution electrode refers to an electrode where a hydrogen evolution reaction (HER) occurs.

[0109] Hereinafter, the oxygen generation electrode, the hydrogen generation electrode, and the polymer electrolyte membrane will be sequentially described.

[0110] The oxygen evolution reaction catalyst included in the oxygen evolution electrode includes a noble metal oxide aggregate in which a plurality of noble metal oxide particles including noble metal oxide are aggregated in a nanowire shape. For example, the nanowire shape refers to a shape in which noble metal oxide particles are aggregated in a lengthwise direction and have a very large aspect ratio, which is the ratio of length to diameter. Therefore, the noble metal oxide aggregate is different from a form in which noble metal oxide particles are aggregated to have mesopores as described above, or a mesoporous structure in which nanowires or nanorods are aggregated to have mesopores and are integrated.

[0111] The above-mentioned oxygen generation reaction catalyst may be manufactured according to the above-mentioned manufacturing method.

[0112] As described above, the noble metal oxide aggregate may have an increased surface area due to pores between the plurality of noble metal oxide particles. For example, the BET specific surface area of ​​the noble metal oxide aggregate may be within a predetermined range. The BET specific surface area is determined according to the method described in the "BET specific surface area measurement" section of Evaluation Example 1 below.

[0113] For example, the lower limit of the BET surface area is 50 m 2 / g, 55 m 2 / g, 60 m 2 / g, 65 m 2 / g, 70 m 2 / g, 75 m 2 / g, 80 m 2 / g, 85 m 2 / g, 90 m 2 / g, 95 m 2 / g, 100 m 2 / g, 105 m 2 / g, 110 m 2 / g, 115 m 2 / g, 120 m 2 / g or 125 m 2 / g can be about, and its upper limit is not particularly limited, but for example, 400 m 2 / g, 350 m 2 / g, 300 m 2 / g, 250 m 2 / g, 200 m 2 / g, 150 m 2 / g or 100 m 2 It could be around / g.

[0114] The BET specific surface area may be greater than or equal to any one of the lower limits described above; or may be greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0115] Since the above-described noble metal oxide aggregate has a BET specific surface area within the aforementioned range, performance and durability can be improved. The above-described noble metal oxide particles are laminated into a plurality of layers along the longitudinal direction of the above-described noble metal oxide aggregate, and each of the layers can include a plurality of the above-described noble metal oxide particles.

[0116] As described above, the noble metal oxide aggregate is laminated into multiple layers, and the layers include multiple noble metal oxide particles, so that the above-described BET surface area value can be satisfied.

[0117] The diameter and length of the above noble metal oxide aggregate may be within a predetermined range. The diameter was measured by photographing the noble metal oxide aggregate using a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0118] For example, the lower limit of the diameter of the noble metal oxide aggregate may be about 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm, and the upper limit may be about 200 nm, 150 nm, 100 nm, 90 nm, 80 nm, 70 nm, 60 nm or 50 nm.

[0119] The lower limit of the length of the above noble metal oxide aggregate may be about 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm or 600 nm, and the upper limit may be about 800 nm, 780 nm, 760 nm, 740 nm, 720 nm, 700 nm, 680 nm, 660 nm, 640 nm, 620 nm or 600 nm.

[0120] The diameter and length of the above-described noble metal oxide aggregate may each have a range of being equal to or greater than any one of the lower limits described above; being equal to or less than any one of the upper limits described above; or being equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0121] The above precious metal oxide may refer to a final material formed from a precursor of the above-mentioned precious metal oxide.

[0122] The above precious metal oxide may be iridium oxide, an oxide of an iridium alloy, or a combination thereof.

[0123] For example, the noble metal oxide is IrO x (where x is an integer from 1 to 3), IrMO x (wherein M includes Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof, and x is an integer from 1 to 3) or a combination thereof.

[0124] By including the oxygen generation reaction catalyst in the oxygen generation electrode, performance and durability can be improved.

[0125] The above oxygen generation electrode may include an oxygen generation reaction catalyst within a predetermined range with respect to the total weight of the oxygen generation electrode.

[0126] For example, the lower limit of the content of the catalyst for the oxygen generation reaction may be about 70 wt% or 72 wt%, and the upper limit may be about 95 wt% or 90 wt%.

[0127] The content of the catalyst for the oxygen generation reaction may be in a range of more than or exceeding any one of the lower limits described above; less than or equal to any one of the upper limits described above; or more than or exceeding any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0128] The above oxygen generation electrode may further include an ion conductor to improve the adhesion of the catalyst and transfer hydrogen ions.

[0129] The above ion conductor may include a cation exchanger to ensure ion conductivity.

[0130] The above cation exchanger may be a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, a phosphonic acid group, an imide group, a sulfonimide group, a sulfonamide group, or a sulfonic acid fluoride.

[0131] The above ion conductor may be a fluorine-based ion conductor, a hydrocarbon-based ion conductor, or a mixture thereof.

[0132] The above fluorine-based ion conductor may be a fluorine-based polymer having the cation exchange group in the side chain and containing fluorine in the main chain, for example, poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), etc.

[0133] The hydrocarbon-based ion conductor is a hydrocarbon-based polymer having the cation exchange group in the side chain [e.g., sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, sulfonated polyquinoxaline, sulfonated polyketone, sulfonated polyphenylene oxide, sulfonated polyether sulfone, Sulfonated polyether ketone, sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether, sulfonated polyarylene ether nitrile, sulfonated polyarylene ether ether nitrile,It may be polyarylene ether sulfone ketone, etc.

[0134] According to one embodiment, the ion conductor may have hydrogen ion conductivity.

[0135] The ion conductor having the above hydrogen ion conductivity can also substitute H with Na, K, Li, Cs or tetrabutylammonium in the cation exchanger at the end of the side chain. When substituting H with Na in the ion exchanger at the end of the side chain, NaOH is used during the preparation of the catalyst composition, and when substituting H with tetrabutylammonium, tetrabutylammonium hydroxide is used. K, Li or Cs can also be substituted using an appropriate compound. Since this substitution method is widely known in the art, a detailed description thereof will be omitted herein.

[0136] The content of the above ion conductor can be appropriately adjusted as needed. In one example, the lower limit of the content of the ion conductor relative to 100 parts by weight of the oxygen generation reaction catalyst can be about 5 or 7 parts by weight, and the upper limit can be about 30 parts by weight or 28 parts by weight.

[0137] The ion conductor may have a range of at least or exceeding any one of the lower limits described above, relative to 100 parts by weight of the oxygen evolution reaction catalyst; or at most or exceeding any one of the upper limits described above, or at most or exceeding any one of the lower limits described above, and at most or less than any one of the upper limits described above. When the ion conductor is within the above range, the performance and durability are excellent.

[0138] The above ion conductor can be used as a single substance or as a mixture, and may also be optionally used together with a non-conductive compound to further enhance adhesion to the polymer electrolyte membrane. The content of the non-conductive compound can be appropriately adjusted depending on the intended use.

[0139] As the above non-conductive compound, at least one selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene / tetrafluoroethylene (ETFE), ethylene chlorotrifluoro-ethylene copolymer (ECTFE), polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), dodecylbenzenesulfonic acid, and sorbitol can be used.

[0140] The above hydrogen generation electrode may include a catalyst for hydrogen generation reaction. The catalyst for hydrogen generation reaction may include active particles and a carrier.

[0141] The above active particles may include a precious metal.

[0142] For example, the precious metal may be a platinum-based precious metal.

[0143] The platinum-based precious metal may be platinum (Pt) and / or a Pt-M alloy. The M may be palladium (Pd), ruthenium (Ru), iridium (Ir), osmium (Os), gallium (Ga), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), silver (Ag), gold (Au), zinc (Zn), tin (Sn), molybdenum (Mo), tungsten (W), lanthanum (La), or rhodium (Rh).

[0144] Specifically, the Pt-M alloy includes Pt-Pd, Pt-Sn, Pt-Mo, Pt-Cr, Pt-W, Pt-Ru, Pt-Ni, Pt-Co, Pt-Y, Pt-Ru-W, Pt-Ru-Ni, Pt-Ru-Mo, Pt-Ru-Rh-Ni, Pt-Ru-Sn-W, Pt-Ru-Ir-Ni, Pt-Co-Mn, Pt-Co-Ni, Pt-Co-Fe, Pt-Co-Ir, Pt-Co-S, Pt-Co-P, Pt-Fe, Pt-Fe-Ir, Pt-Fe-S, Pt-Fe-P, Pt-Au-Co, Pt-Au-Fe, Pt-Au-Ni, Pt-Ni, Pt-Ni-Ir, Pt-Cr, Pt-Cr-Ir, or these Mixtures can be used.

[0145] The above carrier may be a carbon-based carrier.

[0146] The carbon-based carrier may be graphite, super P, carbon fiber, carbon sheet, carbon black, Ketjen Black, Denka black, acetylene black, carbon nanotube (CNT), carbon sphere, carbon ribbon, fullerene, activated carbon, carbon nanofiber, carbon nanowire, carbon nanoball, carbon nanohorn, carbon nanocage, carbon nanoring, ordered nano- / meso-porous carbon, carbon aerogel, mesoporous carbon, graphene, stabilized carbon, activated carbon, or a combination thereof.

[0147] The above oxygen generation electrode and the above hydrogen generation electrode may each include only a catalyst layer including a catalyst for oxygen generation reaction and a catalyst for hydrogen generation reaction, but may include an electrode substrate together with the catalyst layer.

[0148] At this time, the electrode substrate can play a role in supporting the electrode and diffusing the fuel and oxidant to the catalyst layer.

[0149] The electrode substrate may include a microporous layer, a porous diffusion layer, or a combination thereof.

[0150] The above microporous layer serves to enhance the diffusion effect of the reactant, and may generally include a conductive powder having a small particle size, for example, carbon powder, carbon black, acetylene black, activated carbon, metal oxide nanowires, carbon fibers, fullerene, carbon nanotubes, carbon nanowires, carbon nano-horns, or carbon nano rings.

[0151] The above porous diffusion layer is made of porous titanium, carbon paper, carbon cloth, carbon felt or metal cloth (a porous film made of metal cloth in a fibrous state or a metal film formed on the surface of a cloth formed of polymer fibers).

[0152] The above microporous layer and the above porous diffusion layer may include known materials in addition to those exemplified above.

[0153] The above electrode substrate can be treated with a water-repellent fluorine resin, in which case the diffusion efficiency of reactants can be prevented from being reduced by water generated during operation of the electrolysis cell.

[0154] As the above fluorine-based resin, polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, fluorinated ethylene propylene, polychlorotrifluoroethylene or a copolymer thereof can be used.

[0155] The above polymer electrolyte membrane has an ion exchange function that moves hydrogen ions generated at an oxygen generation electrode to a catalyst for hydrogen generation reaction.

[0156] A polymer electrolyte membrane according to one embodiment may include a porous support including a plurality of pores, and an ion conductor filling the pores of the porous support.

[0157] The above porous support may be a fluorine-based support or a nano web support.

[0158] The fluorine-based support may correspond to, for example, expanded polytetrafluoroethylene (e-PTFE) having a microstructure of polymer fibrils or a microstructure in which nodes are interconnected by fibrils. In addition, a film having a microstructure of polymer fibrils without nodes may also be used as the porous support.

[0159] The above nano web support may be a support in which nano fibers are integrated in the form of a non-woven fabric containing a large number of pores.

[0160] The above ion conductor is as described above.

[0161] The ion conductor included in the polymer electrolyte membrane may be the same as or different from the ion conductor included in the oxygen generation electrode. For example, the ion conductor included in the polymer electrolyte membrane may be the same as the ion conductor included in the oxygen generation electrode.

[0162]

[0163] 3. Susan Hae-cell

[0164] In one embodiment, the electrolysis cell comprises a membrane-electrode assembly for the electrolysis cell.

[0165] The above electrolytic cell is the same as the known one except that it includes a membrane-electrode assembly according to the present application, and therefore a detailed description thereof is omitted.

[0166] Hereinafter, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0167]

[0168] Example 1.

[0169] (a) 100 mg and 300 mg of IrCl4 from Sigma-Aldrich, a precursor of precious metal oxides, and oxalic acid from Sigma-Aldrich, a weak reducing agent, were placed in a reaction vessel together with 100 ml of water (H2O), and then subjected to a hydrothermal reaction to produce multiple IrO x A solution in which seeds were formed was prepared. At this time, the hydrothermal reaction was carried out for 1 hour at a temperature of 80°C. The plurality of IrO x The seeds had a diameter of approximately 10 nm.

[0170] (n) The above multiple IrO x Adding 100 mg of the above-mentioned reducing agent to the solution in which the seeds are formed, the solution is injected into a substrate and an AAO film including a plurality of pores penetrating the substrate in the thickness direction, and a vacuum adsorption process is performed for 40 minutes under a pressure of 10 kPa, and then a hydrothermal reaction is performed to form the plurality of IrO x The seeds were aggregated. At this time, the diameter of the pores was approximately 50 nm, and the hydrothermal reaction was carried out at a temperature of 80°C for 1 hour.

[0171] (ㄷ) The above-mentioned multiple IrO xThe seeds are finally heat treated to strengthen the bonding between the seeds, and the AAO film is removed to obtain IrO having a nanowire shape. x A particle aggregate was formed. At this time, the heat treatment was performed at a temperature of 450°C for 2 hours.

[0172] The above IrO x The particle aggregate has a nanowire shape as shown in the scanning electron microscope (SEM) image of Fig. 3, and the IrO x As a result of photographing and measuring the particle aggregate, the diameter of the aggregate was about 50 nm, and the length of the aggregate was about 600 nm.

[0173]

[0174] Example 2.

[0175] In the above (a), IrSnO was prepared in the same manner as in Example 1, except that 70 mg of IrCl4 from Sigma-Aldrich and 30 mg of SnCl4 from Sigma-Aldrich were added instead of 100 mg of IrCl4 from Sigma-Aldrich as a precursor of the noble metal oxide. x A particle aggregate was manufactured.

[0176] The above multiple IrSnO x The seeds had a diameter of approximately 10 nm.

[0177] The above IrSnO x The particle aggregate has a nanowire shape as shown in the transmission electron microscope (TEM) image of Fig. 4, and the IrSnO x As a result of photographing and measuring the particle aggregate, the diameter of the aggregate was about 50 nm, and the length of the aggregate was about 550 nm.

[0178]

[0179] Comparative example.

[0180] commercial IrOx (Alfa Aesar, 43396) was used.

[0181]

[0182] Evaluation Example 1. BET Surface Area Measurement

[0183] A 0.1 g sample of the oxygen evolution reaction catalyst of the electrolysis cell manufactured in Examples 1 to 2 and Comparative Examples was added to a tube, degassing treatment was performed at 150°C for 4 hours, and measurement was performed using ASAP2020 from Micromeritics. Measurements were performed three times for the same sample, and the average value is shown in Table 1 below. In addition, the measurement results of the BET specific surface area are as shown in Fig. 5.

[0184] Example 1 Example 2 Comparative Example BET specific surface area (m 2 / g)9312545

[0185] Evaluation Example 2. IV Characteristics An electrode slurry was prepared by adding 20 parts by weight of an ion conductor dispersion and a solvent to 100 parts by weight of the oxygen evolution reaction catalyst of the electrolysis cell manufactured in Examples 1 to 2 and Comparative Example, and the electrode slurry was directly coated on a polymer electrolyte membrane (Chemours, NR212) and then dried at 90°C for 30 minutes to prepare a membrane-electrode assembly for an electrolysis cell.

[0186] The membrane-electrode assembly for the electrolysis cell manufactured above was applied inside a unit cell designed and manufactured for the electrolysis cell, and the voltage and resistance were measured at specific currents from 1 mA to 20 A under conditions of a cell temperature of 80°C, a water temperature of 80°C, and a flow rate of 5 ml / min using a protocol for measuring the voltage and resistance, and the measurement was stopped at 2 V.

[0187] The result at this time is as shown in Fig. 6.

[0188]

[0189] result

[0190] According to Table 1 and Fig. 5, it can be confirmed that the BET specific surface area of ​​the oxygen evolution reaction catalyst of Examples 1 and 2, which formed a plurality of precious metal oxide seeds and aggregated them to form a precious metal oxide aggregate, increased compared to the comparative example that did not.

[0191] According to Table 2 and Fig. 6, it can be confirmed that the membrane-electrode assembly including the oxygen evolution reaction catalyst of Examples 1 and 2, which formed a plurality of noble metal oxide seeds and aggregated them to form a noble metal oxide aggregate, exhibited improved performance by showing a higher current density at the same voltage compared to the membrane-electrode assembly including the oxygen evolution reaction catalyst of the comparative example, which did not form a plurality of noble metal oxide seeds.

[0192]

[0193] Although the preferred embodiments have been described in detail above, the scope of the rights is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the rights.

[0194]

[0195] [Explanation of symbols]

[0196] 100: Membrane-electrode assembly for electrolysis cell

[0197] 10: Oxygen generation electrode

[0198] 20: Hydrogen generation electrode

[0199] 30: Polymer electrolyte membrane

Claims

1. Forming multiple precious metal oxide seeds by hydrothermal reaction of a precursor of a precious metal oxide, A solution containing the above plurality of precious metal oxide seeds is injected into a mold to coagulate the above plurality of precious metal oxide seeds, Forming a noble metal oxide aggregate by performing heat treatment on the above-mentioned plurality of noble metal oxide seeds A method for producing a catalyst for oxygen generation reaction in a water electrolysis cell including a.

2. In paragraph 1, A method for producing a catalyst for an oxygen evolution reaction in a water electrolysis cell, wherein the precursor of the above noble metal oxide comprises iridium (Ir) chloride, iridium acetate, iridium aminide, iridium sulfide, or a combination thereof.

3. In paragraph 2, A method for producing a catalyst for an oxygen evolution reaction in a water electrolysis cell, wherein the precursor of the above noble metal oxide further comprises a chloride, acetate, amine, sulfide, or combination thereof of a noble metal including Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof.

4. In paragraph 1, A method for producing a catalyst for oxygen generation reaction in a water electrolysis cell, wherein the above hydrothermal reaction is performed at a temperature in the range of 60°C to 120°C for 0.5 to 3 hours.

5. In paragraph 1, A method for producing a catalyst for oxygen evolution reaction in a water electrolysis cell, wherein the diameter of the precious metal oxide seed is in the range of 2 nm to 50 nm.

6. In paragraph 1, A method for producing a catalyst for oxygen evolution reaction of a water electrolysis cell, wherein the mold is an anodic aluminum oxide membrane (AAO), a cellulose membrane, a polycarbonate membrane or a nylon membrane, which comprises a substrate and a plurality of pores penetrating the substrate in the thickness direction.

7. In paragraph 6, A method for producing a catalyst for oxygen generation reaction in a water electrolysis cell, wherein the pore diameter of the above mold is in the range of 10 nm to 200 nm.

8. In paragraph 6, A method for producing a catalyst for oxygen evolution reaction in a water electrolysis cell, wherein the above plurality of noble metal oxide seeds are laminated in a plurality of layers within the pores of the mold, and each of the layers contains a plurality of the above noble metal oxide seeds.

9. In paragraph 1, After being injected into the above mold, a vacuum adsorption process is further performed. A method for producing a catalyst for oxygen generation reaction in a water electrolysis cell, wherein the above vacuum adsorption process is performed under a pressure in the range of 5 kPa to 20 kPa for 10 to 100 minutes.

10. In paragraph 1, A method for producing a catalyst for oxygen generation reaction in a water electrolysis cell, wherein the above heat treatment is performed at a temperature in the range of 350°C to 600°C for 0.5 to 4 hours.

11. In paragraph 1, The above noble metal oxide aggregate is a method for producing a catalyst for oxygen evolution reaction in a water electrolysis cell having a nanowire shape.

12. Polymer electrolyte membrane; An oxygen evolution electrode positioned on one side of the polymer electrolyte membrane and including a catalyst for oxygen evolution reaction; and A hydrogen generation electrode positioned on the other side of the polymer electrolyte membrane; The above oxygen generation reaction catalyst is a membrane-electrode assembly for a water electrolysis cell comprising a noble metal oxide aggregate in which a plurality of noble metal oxide particles including noble metal oxide are aggregated in the shape of nanowires.

13. In paragraph 12, The above noble metal oxide complex has a BET surface area of ​​50 m 2 Membrane-electrode assembly for electrolysis cells having a mass of / g or more.

14. In paragraph 12, A membrane-electrode assembly for a water electrolysis cell, wherein the noble metal oxide particles are laminated into a plurality of layers along the longitudinal direction of the noble metal oxide aggregate, and each of the layers contains a plurality of the noble metal oxide particles.

15. In paragraph 12, The diameter of the above noble metal oxide aggregate is in the range of 10 nm to 200 nm, A membrane-electrode assembly for a water electrolysis cell, wherein the length of the above noble metal oxide aggregate is in the range of 150 nm to 800 nm.

16. In paragraph 12, The above precious metal oxide is IrO x (where x is an integer from 1 to 3), IrMO x (wherein M comprises Ru, Pt, Sn, Se, Sb, Ta, Te, Nb, W, Zn, Au, or a combination thereof, and x is an integer from 1 to 3) or a combination thereof. A membrane-electrode assembly for a water electrolysis cell.

17. In paragraph 12, The above oxygen generation electrode further includes an ion conductor, The above oxygen generation electrode is a membrane electrode assembly for a water electrolysis cell, which contains the oxygen generation reaction catalyst in an amount of 70 to 95 wt% based on the total weight of the oxygen generation electrode.

18. In paragraph 12, The above hydrogen generation electrode is, A membrane-electrode assembly for a water electrolysis cell, comprising a carbon-based carrier and a hydrogen-generation catalyst supported on the carbon-based carrier and including active particles including a precious metal.

19. In paragraph 12, A membrane-electrode assembly for a water electrolysis cell, wherein the polymer electrolyte membrane comprises a porous support including a plurality of pores, and an ion conductor filling the pores of the porous support.

20. A water electrolysis cell comprising a membrane electrode assembly according to claim 12.

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