Catalyst for oxygen evolution reaction of water electrolyzer, method for manufacturing the same, membrane electrode assembly for water electrolyzer comprising the same, and water electrolyzer

Abstract

The present application provides a catalyst for oxygen evolution reaction of water electrolysis cell, comprising: a carrier containing fluorine-doped metal oxide; and water electrolysis catalyst particles located on the surface of the carrier and containing fluorine-doped noble metal or fluorine-doped noble metal oxide; wherein the content of fluorine in the entire fluorine-doped metal oxide is 1at% to 20at% relative to the total composition of 100at% measured by high-resolution transmission electron microscopy (TEM) energy dispersive X-ray spectroscopy analysis, and the content of fluorine in the entire fluorine-doped noble metal oxide is 1at% to 20at% relative to the total composition of 100at% measured by high-resolution transmission electron microscopy energy dispersive X-ray spectroscopy analysis.

Description

Technical Field

[0001] This invention relates to a catalyst for the oxygen evolution reaction in a water electrolyzer and a method for manufacturing the same, a membrane electrode assembly containing the catalyst for a water electrolyzer, and a water electrolyzer.

[0002] This research was conducted with funding from the Ministry of Trade, Industry and Energy of Korea (MOTIE) and the Korea Energy Technology Evaluation Institute (KETEP) (Project No.: 20223030040220). Background Technology

[0003] Recent energy demands and environmental requirements necessitate the development of sustainable, environmentally friendly, and efficient energy sources, with hydrogen, as a raw material for renewable energy, receiving widespread attention.

[0004] Based on the production method, hydrogen energy can be divided into gray hydrogen, blue hydrogen, and green hydrogen. Gray hydrogen and blue hydrogen use fossil fuels, producing carbon dioxide during the production process, or the carbon dioxide emissions cannot be completely eliminated. Green hydrogen refers to hydrogen produced by water electrolysis. Because the production of green hydrogen does not produce carbon dioxide, it has attracted much attention as an ideal environmentally friendly energy source. The production of green hydrogen requires the use of water electrolysis technology.

[0005] Water electrolysis technology refers to the electrochemical technique of producing hydrogen and oxygen by electrolyzing water and using membranes to facilitate ion movement. Water electrolysis can be divided into two half-cell reactions: one is the hydrogen evolution reaction (HER) that occurs at the reduction electrode, and the other is the oxygen evolution reaction (OER) that occurs at the oxidation electrode.

[0006] Regarding water electrolysis catalysts, especially catalysts for the oxygen evolution electrode in polymer electrolyte membrane (PEM) water electrolysis, iridium black and iridium oxide powder have been used as catalysts for the oxygen evolution reaction in the conventional PEM water electrolysis oxygen evolution electrode. However, due to their low dispersibility, low conductivity and poor stability, improvements are needed. Summary of the Invention

[0007] Technical issues

[0008] A catalyst for the oxygen evolution reaction in a water electrolyzer is provided, which reduces the amount of precious metals used and exhibits high electrochemical durability and conductivity when applied to the electrode of a water electrolyzer, even in the high voltage and low pH water electrolysis operating environment.

[0009] Technical solution

[0010] In one embodiment, a catalyst for the oxygen evolution reaction in a water electrolysis cell is provided, comprising: a support containing a fluorine-doped metal oxide; and water electrolysis catalyst particles located on the surface of the support and containing a fluorine-doped noble metal or a fluorine-doped noble metal oxide; wherein the fluorine content in the entire fluorine-doped metal oxide, as determined by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy, is 1 at% to 20 at% of the total composition, and the fluorine content in the entire fluorine-doped noble metal or fluorine-doped noble metal oxide, as determined by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy, is 1 at% to 20 at% of the total composition.

[0011] In another embodiment, an oxygen evolution electrode is provided, comprising: the catalyst described above for the oxygen evolution reaction in a water electrolysis cell.

[0012] In another embodiment, a method for manufacturing an oxygen evolution electrode is provided, comprising: (i) mixing a metal oxide into a solution containing a noble metal oxide precursor and then drying it to produce a dried product; (ii) mixing the dried product with a fluorine precursor and then heat-treating it to produce a catalyst for an oxygen evolution reaction in a water electrolyzer; (iii) mixing the catalyst for an oxygen evolution reaction in a water electrolyzer with an ionomer to produce a slurry; and (iv) dispersing the slurry.

[0013] In another embodiment, a membrane electrode assembly for a water electrolysis cell is provided, comprising: a polymer electrolyte membrane; the oxygen evolution electrode located on one side surface of the polymer electrolyte membrane; and a hydrogen evolution electrode located on the other side surface of the polymer electrolyte membrane.

[0014] In another embodiment, a water electrolysis cell is provided, comprising: the membrane electrode assembly for the water electrolysis cell described above.

[0015] Invention Effects

[0016] The catalyst for the oxygen evolution reaction in a water electrolyzer, manufactured according to one embodiment of the present invention, can reduce the amount of precious metals used, and when applied to the electrode of a water electrolyzer, it exhibits high electrochemical catalytic activity and conductivity even in a water electrolysis-driven environment with high voltage and low pH. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a membrane electrode assembly (MEA) used in a water electrolysis cell.

[0018] Figures 2 to 5 It is a high-resolution TEM image of Example 1 and a TEM image mapped by energy dispersive X-ray spectroscopy (EDS).

[0019] Figure 6 The graph shows the water electrolysis performance of the membrane electrode assemblies manufactured in Examples 1, 3, Comparative Example 1, and Comparative Example 2. Detailed Implementation

[0020] The following detailed description of specific embodiments is provided to enable those skilled in the art to readily implement these embodiments. However, the present invention can be implemented in various different forms and is not limited to the embodiments described herein.

[0021] The terminology used herein is for illustrative purposes only and is not intended to limit the invention. Unless the context clearly indicates otherwise, singular expressions include plural expressions.

[0022] "Combinations" refers to mixtures, laminates, complexes, copolymers, alloys, miscibles, reaction products, etc. of the components.

[0023] Terms such as “include,” “possess,” or “have” should be understood as being intended to specify the presence of a feature, quantity, step, component, or combination thereof being implemented, without pre-excluding the possibility of the presence or addition of one or more other features, quantities, steps, components, or combinations thereof.

[0024] The accompanying drawings have been enlarged to show the thickness in order to clearly represent multiple layers and regions, and similar components are labeled with the same reference numerals throughout the specification. When referring to a portion of a layer, film, region, or plate as being "on" or "above" another portion, this includes not only the case where it is "immediately adjacent" to another portion on top of it, but also the case where there is another portion in between. Conversely, when a component is described as being "immediately adjacent" to another portion on top of it, it means that there are no other portions in between.

[0025] "Layer" includes not only the shape formed on the entire surface when viewed from above, but also the shape formed on a portion of the surface.

[0026] The average particle size can be measured using methods known to those skilled in the art, such as using a particle size analyzer or using transmission electron microscopy (TEM) or scanning electron microscopy (SEM) images. Alternatively, it can be measured and analyzed using dynamic light scattering, where the average particle size is calculated by counting the number of particles for each particle size range. Unless otherwise defined, the average particle size can refer to the diameter D of particles that constitute 50% of the total volume in the particle size distribution. 50 Furthermore, unless otherwise defined, the average particle size may also refer to the particle size distribution obtained by measuring the size (diameter or major axis length) of more than 20 randomly selected particles from a scanning electron microscope image of water electrolysis catalyst particles, and the diameter D of the particles that constitute 50% of the total volume in this particle size distribution. 50 As the average particle size.

[0027] "Or" should not be interpreted as exclusive; for example, "A or B" should be interpreted as including A, B, A+B, etc.

[0028] The term "metal" is interpreted as encompassing common metals, transition metals, and metalloids (semi-metals).

[0029] Catalysts for the oxygen evolution reaction

[0030] In this specification, the catalyst used for the oxygen evolution reaction (OER) refers to the catalyst applied to the electrode where the OER occurs (hereinafter referred to as the OER electrode). That is, it means the catalyst included in the OER electrode described later.

[0031] According to one embodiment, the catalyst for the oxygen evolution reaction in a water electrolysis cell comprises: a support containing a fluorine-doped metal oxide; and water electrolysis catalyst particles located on the surface of the support and containing a fluorine-doped noble metal or a fluorine-doped noble metal oxide; wherein the fluorine content in the entire fluorine-doped metal oxide, as measured by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDS), is 1 at% to 20 at% of the total composition, and the fluorine content in the entire fluorine-doped noble metal or fluorine-doped noble metal oxide, as measured by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDS), is 1 at% to 20 at% of the total composition.

[0032] The performance and durability of the catalysts used in the oxygen evolution reaction can be improved by adjusting the type, shape, and content of the support and water electrolysis catalyst particles.

[0033] In polymer electrolyte membrane water electrolyzers, noble metals or noble metal oxides are used as catalysts for the oxygen evolution reaction (OER). Currently, researchers are actively exploring the loading of noble metal oxide catalysts onto supports to reduce the amount of expensive noble metal oxides used and increase the specific surface area. However, the low conductivity of the support necessitates a high concentration of noble metal; therefore, it is necessary to develop supports that can compensate for the low conductivity and reduce the amount of noble metal used. To this end, in one embodiment, this paper proposes a water electrolysis electrode that uses a fluorine-doped noble metal or a fluorine-doped noble metal oxide as the OER catalyst and a fluorine-doped metal oxide as the support. This solves the problem of defluorination reactions occurring during the solvation process due to the excessive reactivity of fluorine, making it difficult to control the doping amount and achieve uniform fluorine doping. Furthermore, the uniformly fluorine-doped noble metal or fluorine-doped noble metal oxide reduces the energy of the rate-determining step caused by fluorine doping, resulting in improved electrochemical activity. Simultaneously, based on the fluorine-doped metal oxide support, it exhibits high conductivity and excellent electrochemical corrosion resistance.

[0034] carrier

[0035] According to one embodiment, the support contains a fluorine-doped metal oxide, such as tungsten (W), titanium (Ti), nickel (Ni), ruthenium (Ru), tantalum (Ta), tin (Sn), cobalt (Co), or combinations thereof. Therefore, the metal oxide can include tungsten oxide, titanium oxide, nickel oxide, ruthenium oxide, tantalum oxide, tin oxide, cobalt oxide, or combinations thereof, preferably tin oxide. When the catalyst used for the oxygen evolution reaction in a water electrolyzer contains the above-mentioned support, it has the advantage that, by compensating for the low conductivity of the water electrolyzer catalyst particles containing noble metal oxides, high catalytic activity can be exhibited even with a low noble metal content. Furthermore, since the metal oxide contained in the support is doped with fluorine, the dissolution of the doped fluorine or the metal in the metal oxide in the water electrolysis driving environment can be prevented, thereby preventing a decline in membrane electrode performance.

[0036] The aforementioned carrier can have various shapes, such as spherical, linear, or rod-shaped, and more specifically, it can be spherical. The aforementioned carrier can also take the form of secondary particles formed by the aggregation of primary particles, wherein the average particle size D of the primary particles is... 50 The particle size can be 0.005 μm to 0.5 μm, for example, 0.007 μm to 0.4 μm, 0.009 μm to 0.3 μm, or 0.01 μm to 0.2 μm. The average particle size D of the above secondary particles... 50 The primary particles can range from 0.05 μm to 1.0 μm, for example, from 0.08 μm to 0.9 μm or from 0.1 μm to 0.8 μm. These primary particles can be microcrystalline particles or grains. Multiple primary particles can form grain boundaries and aggregate to form secondary particles. These primary particles can have various shapes, such as spherical or quasi-spherical (plate-like, etc.). The average particle size can be obtained by measuring the size (diameter or major axis length) of more than 20 randomly selected particles from a scanning electron microscope image of the carrier, and the diameter D of the particles that constitute 50% of the total volume in the above particle size distribution is taken as the particle size distribution. 50 As the average particle size. According to one embodiment, the catalyst used for the oxygen evolution reaction in a water electrolyzer can be in the form of water electrolyzer catalyst particles located on the surface of the aforementioned support, thereby forming a conductive network, reducing the surface resistance of the electrodes, and improving the performance of the water electrolyzer.

[0037] In one embodiment, relative to the total 100% by weight of the aforementioned support and water electrolysis catalyst particles, 20% to 80% by weight of the aforementioned support may be included, for example, 25% to 65% by weight or 30% to 50% by weight of the aforementioned support. When the contents of the support and water electrolysis catalyst particles are as described above, the catalyst for the oxygen evolution reaction containing this substance can form a conductive network, thereby reducing the surface resistance of the electrode and improving the performance of the water electrolysis cell.

[0038] In one embodiment, the fluorine content in the entire fluorine-doped metal oxide, as measured by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDS), relative to 100 at% of the total composition, is 1 at% to 20 at%, for example, 1 at% to 15 at%, 1 at% to 12 at%, 4 at% to 12 at%, or 8 at% to 12 at%. When the fluorine content in the entire fluorine-doped metal oxide meets the above range, uniform fluorine doping can be achieved, thereby reducing the surface resistance of the electrode and improving the performance of the water electrolysis cell.

[0039] Water electrolysis catalyst particles

[0040] In one embodiment, the water electrolysis catalyst particles are located on the surface of the aforementioned support and contain fluorine-doped noble metals or fluorine-doped noble metal oxides. The noble metal can be a non-platinum based precious metal. For example, the non-platinum based precious metal may include palladium (Pd), ruthenium (Ru), iridium (Ir), alloys thereof, or combinations thereof. According to one embodiment, the noble metal oxide may include IrO. x (where x is an integer from 1 to 3), RuO x (where x is an integer from 1 to 3), PdO x (where x is an integer from 1 to 3), IrMO x (Where M includes Ru, Sn, Ti, Te, Nb or combinations thereof, and x is an integer from 1 to 3) or combinations thereof. When the water electrolysis catalyst particles contain the above-mentioned noble metal oxides, their advantage lies in exhibiting high catalytic activity.

[0041] The average particle size D of the above water electrolysis catalyst particles 50 The particle size can range from 0.001 μm to 0.015 μm, for example, from 0.002 μm to 0.012 μm or from 0.004 μm to 0.01 μm. The average particle size described above can be obtained by measuring the size (diameter or major axis length) of more than 20 randomly selected particles from a scanning electron microscope image of the water electrolysis catalyst particles. The diameter D of the particles representing 50% of the total volume in the above particle size distribution is then calculated. 50As the average particle size. According to one embodiment, the catalyst used for the oxygen evolution reaction in a water electrolysis cell can be in the form of water electrolysis catalyst particles located on the surface of the aforementioned support, thereby forming a conductive network, reducing the surface resistance of the electrodes, and improving the performance of the water electrolysis cell.

[0042] In one embodiment, relative to the total 100% by weight of the above-described support and water electrolysis catalyst particles, 20% to 80% by weight of water electrolysis catalyst particles may be included, for example, 40% to 75% by weight or 50% to 70% by weight of water electrolysis catalyst particles. When the contents of the support and water electrolysis catalyst particles are as described above, the catalyst for the oxygen evolution reaction containing this substance can form a conductive network, thereby reducing the surface resistance of the electrode and improving the performance of the water electrolysis cell.

[0043] The fluorine content relative to 100 at% of the total composition in the entire fluorine-doped noble metal oxide, as measured by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy (EDS), is 1 at% to 20 at%, for example, 2 at% to 19 at% or 3 at% to 10 at%. When the fluorine content in the entire fluorine-doped noble metal oxide meets the above range, uniform fluorine doping can be achieved, thereby reducing the energy of the rate-determining step of electrolysis, thus improving electrochemical activity and enhancing the performance of the water electrolyzer.

[0044] According to one embodiment, a catalyst for the oxygen evolution reaction in a water electrolyzer is produced by a one-pot process of doping fluorine onto a support containing a metal oxide and water electrolyzer catalyst particles containing a noble metal or a noble metal oxide. This allows for the manufacture of a catalyst for the oxygen evolution reaction in a water electrolyzer where, while maintaining fluorine doping, water electrolyzer catalyst particles containing a noble metal or a noble metal oxide are loaded, thereby improving both catalytic activity and conductivity. Conversely, if the water electrolyzer catalyst particles are loaded onto the support after manufacturing the fluorine-doped metal oxide support, the highly active fluorine dopant undergoes a defluorination reaction during the loading of the water electrolyzer catalyst particles, resulting in the inability to retain the fluorine doping, leading to a loss of conductivity and a decrease in water electrolysis performance.

[0045] Oxygen Evolution Electrode

[0046] The oxygen evolution electrode mentioned above refers to the electrode where the oxygen evolution reaction (OER) occurs. This oxygen evolution electrode may include the catalyst described above for the oxygen evolution reaction in a water electrolyzer. Since the catalyst for the oxygen evolution reaction in a water electrolyzer has already been described, detailed explanation is omitted.

[0047] The oxygen evolution electrode described above may contain 60% to 95% by weight of catalyst for the oxygen evolution reaction in a water electrolyzer, relative to a total of 100% by weight of the oxygen evolution electrode. For example, it may contain 65% to 85% by weight or 70% to 95% by weight of catalyst for the oxygen evolution reaction in a water electrolyzer.

[0048] The oxygen evolution electrode described above may further include an ion conductor to improve the adhesion of the catalyst and transfer hydrogen ions. The ion conductor may also include a cation exchange group to ensure ion conductivity. In this case, relative to a total of 100% by weight of the oxygen evolution electrode, the oxygen evolution electrode may contain 1% to 25% by weight of the ion conductor, for example, 2% to 20% by weight or 3% to 18% by weight.

[0049] The aforementioned cation exchange groups can be sulfonic acid groups, carboxyl groups, boric acid groups, phosphoric acid groups, phosphonic acid groups, imide groups, sulfonamide groups, sulfonamide groups, or sulfonic acid fluorides.

[0050] The aforementioned ionic conductors can be fluorine-based ionic conductors, hydrocarbon-based ionic conductors, or mixtures thereof. The aforementioned fluorine-based ionic conductors can be fluorinated polymers containing the aforementioned cation exchange groups on their side chains and fluorine in their main chain, such as polyperfluorosulfonic acid and polyperfluorocarboxylic acid. The aforementioned hydrocarbon ion conductors can be hydrocarbon polymers containing the aforementioned cation exchange groups on their side chains, such as 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 polyethersulfone, sulfonated polyetherketone, and sulfonated polyphenylene sulfone. Sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether, sulfonated polyarylene ethernitrile, sulfonated polyarylene etherether nitrile, and sulfonated polyarylene ether sulfone ketone, etc.

[0051] According to one embodiment, the aforementioned ionic conductor can possess hydrogen ion conductivity. The aforementioned ionic conductor with hydrogen ion conductivity can have H replaced by Na, K, Li, Cs, or tetrabutylammonium at the cation exchange group at the end of the side chain. When H is replaced by Na at the ion exchange group at the end of the side chain, NaOH is used in the manufacture of the catalyst composition; when tetrabutylammonium is used, tetrabutylammonium hydroxide is used; K, Li, or Cs can also be replaced by suitable compounds. Since such substitution methods are well known in the art, detailed descriptions are omitted.

[0052] The aforementioned ionic conductors can be used as a single substance or a mixture, or selectively in conjunction with non-conductive compounds to further enhance their adhesion to the polymer electrolyte membrane. The content of the aforementioned non-conductive compounds can be appropriately adjusted according to the intended use. The aforementioned non-conductive compounds may be selected from at least one of polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene / tetrafluoroethylene (ETFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), dodecylbenzenesulfonic acid, and sorbitol.

[0053] Method for manufacturing oxygen evolution electrode

[0054] According to one embodiment, a method for manufacturing an oxygen evolution electrode for a water electrolyzer includes: (i) mixing a metal oxide into a solution containing a noble metal oxide precursor and then drying it to produce a dried product; (ii) mixing the dried product with a fluorine precursor and then heat-treating it to produce a catalyst for the oxygen evolution reaction in a water electrolyzer; (iii) mixing the catalyst for the oxygen evolution reaction in a water electrolyzer with an ionomer to produce a slurry; and (iv) dispersing the slurry.

[0055] According to one embodiment of the method for manufacturing an oxygen evolution electrode for a water electrolysis cell, a fluorine doping process is performed on a mixture of a support containing a metal oxide and water electrolysis catalyst particles containing a noble metal oxide. Specifically, fluorine is simultaneously doped into both the water electrolysis catalyst particles containing a noble metal or noble metal oxide and the support containing a metal oxide in a one-pot process. This produces a water electrolysis electrode that reduces the energy of the rate-determining step of the electrolysis of the noble metal or noble metal oxide, thereby improving electrochemical activity. Furthermore, based on the fluorine-doped metal oxide support, it exhibits high conductivity and electrochemical corrosion resistance. Conversely, if the water electrolysis catalyst particles containing a noble metal or noble metal oxide are loaded onto the support after it has been manufactured, the highly active fluorine dopant undergoes a defluorination reaction during the loading of the water electrolysis catalyst particles, resulting in the inability to retain the fluorine doping. This leads to a loss of conductivity and a decrease in water electrolysis performance. Moreover, an additional process is required to dope fluorine into the water electrolysis catalyst particles containing a noble metal or noble metal oxide.

[0056] In one embodiment, in the step (i) of mixing the metal oxide into a solution containing a noble metal oxide precursor and then drying it to produce a dried product, the type of the noble metal oxide precursor may include IrCl3, IrCl3 hydrate, IrCl4, H2Cl6Ir, Ir(CH3COO)3, or combinations thereof, preferably IrCl3 hydrate. Furthermore, the type of solvent required to produce the solution is not limited, as long as it can dissolve the noble metal oxide precursor. For example, the solvent may include water, alcohol, ethylene glycol, or combinations thereof, wherein the alcohol may be methanol, ethanol, butanol, or isopropanol.

[0057] Relative to the total 100% by weight of the noble metal oxide precursor and metal oxide in step (i) above, the content of the noble metal oxide precursor can be 25% to 88% by weight, for example, 31% to 84% by weight or 57% to 81% by weight. When the content of the noble metal oxide precursor is within the above range, the catalyst containing this substance for the oxygen evolution reaction in the water electrolyzer can form a conductive network, thereby reducing the surface resistance of the electrode and improving the performance of the water electrolyzer.

[0058] In the aforementioned dried material, the carrier containing the metal oxide can be primary particles. In this case, the primary particles can have various shapes, such as spherical or quasi-spherical (plate-like, etc.), and the average particle size (D) of the primary particles... 50 The value can be 0.005μm to 0.5μm, for example, it can be 0.007μm to 0.4μm, 0.009μm to 0.3μm or 0.01μm to 0.2μm.

[0059] In one embodiment, in the step (ii) above, where the dried material is mixed with a fluorine precursor and then heat-treated to manufacture a catalyst for the oxygen evolution reaction in a water electrolyzer, the type of the fluorine precursor may include NH4F, NH4HF2, or a combination thereof, preferably NH4F. In this case, the molar ratio of the dried material to the fluorine precursor can be from 1:1 to 1:30, for example, from 1:1 to 1:20, 1:2 to 1:20, 1:3 to 1:20, 1:8 to 1:20, 1:13 to 1:20, or 1:18 to 1:20. When the molar ratio of the dried material to the fluorine precursor falls within the above range, the amount of doped fluorine can be easily adjusted, thereby achieving uniform fluorine doping, reducing the surface resistance of the electrode, and improving the performance of the water electrolyzer.

[0060] After the above-mentioned mixing process of the dried material and the fluorine precursor, heat treatment can be performed. The heat treatment can be carried out in an inert gas atmosphere or a reducing gas atmosphere, and the heat treatment temperature can be 80℃~450℃, 100℃~430℃ or 120℃~400℃. The heat treatment time can be 4 hours to 8 hours, 4.5 hours to 7.5 hours or 5 hours to 7 hours.

[0061] In the catalyst for the oxygen evolution reaction in a water electrolysis cell, prepared by heat treatment of the aforementioned dried material mixed with a fluorine precursor, the support containing the fluorine-doped metal oxide can be secondary particles. In this case, the secondary particles can be formed by multiple primary particles forming grain boundaries and aggregating with each other, and the average particle size D of the aforementioned secondary particles... 50 The value can be 0.05μm to 1.0μm, for example, 0.08μm to 0.9μm or 0.1μm to 0.8μm.

[0062] In one embodiment, in the step of mixing the catalyst for the oxygen evolution reaction in the water electrolysis cell with the ion polymer to produce a mixture in step (iii), the ion polymer may be a cation conductor having a cation exchange group capable of exchanging cations, or it may be an anion conductor having anion exchange groups capable of exchanging anions such as hydroxide ions, carbonate ions, or bicarbonate ions.

[0063] The aforementioned cation exchange group can be selected from any of the following: sulfonic acid group, carboxyl group, boric acid group, phosphoric acid group, imide group, sulfonimide group, sulfonamide group, and combinations thereof, and is usually sulfonic acid group or carboxyl group.

[0064] The aforementioned cation conductors may include the aforementioned cation exchange groups, and may include: fluorinated polymers containing fluorine in their main chain; hydrocarbon polymers, such as benzimidazole, polyamide, polyamide-imide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyether-imide, polyester, polyethersulfone, polyether-imide, polycarbonate, polystyrene, polyphenylene sulfide, polyether ether ketone, polyether ketone, polyarylether sulfone, polyphosphazene, or polyphenylquinoxaline; partially fluorinated polymers, such as polystyrene-grafted-ethylene-tetrafluoroethylene copolymer or polystyrene-grafted-polytetrafluoroethylene copolymer; sulfonylimide, etc.

[0065] Furthermore, the H in the aforementioned cation conductor can be replaced with Na, K, Li, Cs, or tetrabutylammonium at the cation exchange group at the end of the side chain. When H is replaced with Na at the cation exchange group at the end of the side chain, NaOH is used in the manufacture of the carbon structure composition; when replaced with tetrabutylammonium, tetrabutylammonium hydroxide is used; K, Li, or Cs can also be replaced with suitable compounds.

[0066] The aforementioned anionic conductors can typically be made of metal hydroxide-doped polymers, specifically, metal hydroxide-doped polyethersulfone, polystyrene, ethylene polymers, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polybenzimidazole, or polyethylene glycol, etc.

[0067] Relative to the total of 100% by weight of the catalyst and ionic polymer used in the oxygen evolution reaction of the water electrolyzer, the content of the ionic polymer can be 10% to 45% by weight, for example, 10% to 40% by weight, 10% to 35% by weight, or 10% to 33% by weight. When the content of the ionic polymer falls within the above range, it is advantageous to improve the performance of the water electrolyzer while suppressing the aggregation of ionic polymers due to excessive ionic polymer content.

[0068] In one embodiment, the slurry dispersing step (iv) described above can be manufactured by any dispersion method selected from ultrasonic dispersion, stirring, three-roll milling, ball milling, planetary stirring, high-pressure dispersion, and mixing methods thereof.

[0069] Membrane electrode assembly for water electrolysis cells

[0070] According to one embodiment, the membrane electrode assembly for a water electrolysis cell includes a polymer electrolyte membrane, an oxygen evolution electrode located on one side of the polymer electrolyte membrane, and a hydrogen evolution electrode located on the other side of the polymer electrolyte membrane.

[0071] The membrane electrode assembly used in the above-mentioned water electrolysis cell, such as Figure 1 As shown. According to Figure 1The membrane electrode assembly 20 for a water electrolysis cell includes a polymer electrolyte membrane 25; an oxygen evolution electrode 21 located on one side of the polymer electrolyte membrane; and a hydrogen evolution electrode 22 located on the other side of the polymer electrolyte membrane.

[0072] Since the oxygen evolution electrode has already been described, a detailed explanation will be omitted. The hydrogen evolution electrode and the polymer electrolyte membrane will be described in detail below.

[0073] The aforementioned hydrogen evolution electrode refers to the electrode where the hydrogen evolution reaction (HER) occurs. This electrode may include a catalyst for the HER. The catalyst for the HER may include active particles and a support; the active particles may include a noble metal, which may be a platinum-based noble metal.

[0074] The aforementioned platinum-based precious metals can be platinum (Pt) and / or Pt-M alloys. M can 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).

[0075] Specifically, the aforementioned Pt-M alloy can be 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 mixtures thereof.

[0076] The aforementioned carriers can be carbon-based carriers. These carbon-based carriers can be graphite, super P, carbon fiber, carbon sheet, carbon black, Ketjen black, Danka black, acetylene black, carbon nanotubes (CNTs), carbon spheres, carbon ribbons, fullerenes, activated carbon, carbon nanofibers, carbon nanowires, carbon nanospheres, carbon nanoangles, carbon nanocages, carbon nanorings, ordered nano / mesoporous carbon, carbon aerogels, mesoporous carbon, graphene, stable carbon, activated carbon, or combinations thereof.

[0077] The oxygen evolution electrode and hydrogen evolution electrode described above may each contain only a catalyst layer containing catalysts for the oxygen evolution reaction and hydrogen evolution reaction, respectively, or they may include an electrode substrate together with the catalyst layer. In this case, the electrode substrate serves to support the electrode and simultaneously diffuse the fuel and oxidant into the catalyst layer. The electrode substrate can use any known electrode substrate without particular limitation, but specifically, it can be carbon paper, carbon cloth, carbon felt, or metal cloth (referring to a porous film composed of fibrous metal cloth or a metal film formed on the surface of a cloth formed of polymer fibers) that can be used as a conductive substrate. The electrode substrate can be an electrode substrate treated with a fluorinated resin to prevent water generated during the operation of the water electrolyzer from reducing the reactant diffusion efficiency. The fluorinated resin can be polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, fluorinated ethylene propylene, polychlorotrifluoroethylene, or copolymers thereof.

[0078] In addition to the catalyst layer and electrode substrate, the oxygen evolution electrode and hydrogen evolution electrode described above may also include a microporous layer. This microporous layer promotes reactant diffusion and typically contains conductive powders with small particle sizes, such as carbon powder, carbon black, acetylene black, activated carbon, carbon fibers, fullerenes, carbon nanotubes, carbon nanowires, carbon nanoangles, or carbon nanorings.

[0079] Polymer electrolyte membrane

[0080] The aforementioned polymer electrolyte membrane has ion exchange functionality, used to move hydrogen ions generated by the oxygen evolution electrode to the catalyst for hydrogen evolution reaction. According to one embodiment, the polymer electrolyte membrane may include a porous support having multiple pores and an ion conductor filling the pores of the porous support.

[0081] The aforementioned porous support can be a fluorinated support or a nanostructured support. For example, a fluorinated support can be expanded polytetrafluoroethylene (e-PTFE) with a polymer fibrillary microstructure or a microstructure with interconnected fibrillary nodes. Alternatively, a thin film with a polymer fibrillary microstructure but without nodes can also be used as the aforementioned porous support.

[0082] The aforementioned fluorinated support may include a perfluorinated polymer. The aforementioned porous support can be obtained by extruding dispersed polymeric polytetrafluoroethylene (PTFE) onto a tape in the presence of a lubricant and then stretching the resulting material, thereby obtaining a porous support with more pores and greater strength. Furthermore, the amorphous content of the PTFE can be increased by heat-treating the aforementioned e-PTFE at a temperature above the melting point of the PTFE (approximately 342°C). The e-PTFE film manufactured using the above method can have micropores with different diameters and porosities. The porosity of the e-PTFE film manufactured using the above method is at least 35%, and the diameter of the micropores is approximately 0.01 to 1 μm (micrometers).

[0083] The aforementioned nanofiber support can be a nonwoven fiber web composed of multiple randomly oriented fibers. This nonwoven fiber web refers to a sheet material with a single fiber or filament structure, interlaid in a manner different from woven cloth. This nonwoven fiber web can be manufactured through carding, garnetting, air-laying, wet-laying, melt-blowing, spun bonding, or stitch bonding.

[0084] The aforementioned fibers may contain more than one polymer material, and any material commonly used as a fiber-forming polymer material may be used; specifically, hydrocarbon fiber-forming polymer materials may be used. For example, the aforementioned fiber-forming polymer materials may include: polyolefins, such as polybutene, polypropylene, and polyethylene; polyesters, such as polyethylene terephthalate and polybutylene terephthalate; polyamides (nylon-6 and nylon-6,6); polyurethane polybutene; polylactic acid; polyvinyl alcohol; polyphenylene sulfide; polysulfone; crystal flow polymers; polyethylene-vinyl acetate copolymers; polyacrylonitrile; cyclic polyolefins; polyoxymethylene; polyolefin thermoplastic elastomers; or combinations thereof.

[0085] The aforementioned nanofiber support can be a support integrated with nanofibers in a non-woven form containing multiple pores.

[0086] The aforementioned nanofibers can preferably be made from hydrocarbon polymers that possess excellent chemical resistance and, due to their hydrophobicity, do not require concern about morphological deformation due to moisture in high-humidity environments. Specifically, the aforementioned hydrocarbon polymers may include: nylon, polyimide, polyarylamide, polyetherimide, polyacrylonitrile, polyaniline, polyethylene oxide, polyethylene naphthalate, polybutylene terephthalate, styrene-butadiene rubber, polystyrene, polyvinyl chloride, polyvinyl alcohol, polyvinylidene fluoride, polyvinylbutene, polyurethane, polybenzoxazole, polybenzimidazole, polyamide-imide, polyethylene terephthalate, polyphenylene sulfide, polyethylene, polypropylene, and copolymers thereof, or mixtures thereof.

[0087] The aforementioned nanomesh support is an aggregate of nanofibers randomly arranged by electrospinning. Considering the porosity and thickness of the nanomesh, when the diameter of 50 fibers was measured using a scanning electron microscope (JSM6700F, JEOL) and its average value was calculated, the nanofibers could have an average diameter of 40 nm to 5000 nm. When the average diameter of the nanofibers is within this range, it exhibits excellent mechanical strength while ensuring suitable porosity.

[0088] The thickness of the aforementioned nonwoven fiber web can be 10μm~50μm or 15μm~43μm. When the thickness of the aforementioned nonwoven fiber web is within the above range, its mechanical strength, lightweight, and integration can reach excellent levels. The basis weight of the aforementioned nonwoven fiber web can be 5~30mg / cm². If the basis weight of the aforementioned nonwoven fiber web is less than the above value range, visible pores may form, making it difficult for it to function as a porous support; if the basis weight is greater than the above value range, it can be made into a form of paper or fabric with almost no pores. The aforementioned porosity can be calculated according to the following formula 1 based on the ratio of the air volume within the aforementioned porous support to the total volume of the porous support. In this case, the aforementioned total volume can be calculated by manufacturing a rectangular sample and measuring its width, length, and thickness, and the air volume can be obtained by subtracting the polymer volume derived from the density from the total volume after measuring the sample mass.

[0089] [Formula 1]

[0090] Porosity (%) = (Volume of air in the porous support / Total volume of the porous support) × 100

[0091] For example, the porosity of the aforementioned porous support can be 30% to 90%. When the porosity of the aforementioned porous support is within the above range, there will be no problem of reduced impregnation of the ionic conductor or reduced stability that would prevent subsequent processes from proceeding smoothly.

[0092] The ionic conductor described above is as described. The ionic conductor contained in the polymer electrolyte membrane may be the same as or different from the ionic conductor contained in the oxygen evolution electrode; as an example, the ionic conductor contained in the polymer electrolyte membrane may be the same as the ionic conductor contained in the oxygen evolution electrode.

[0093] Water electrolysis cell

[0094] In one embodiment, the water electrolysis cell includes the membrane electrode assembly for the water electrolysis cell described above.

[0095] The water electrolysis cell described above is the same as known electrolysis cells, except that it includes the membrane electrode assembly according to this application, so detailed description is omitted.

[0096]

Embodiments of the Invention

[0097] The following describes embodiments and comparative examples of the present invention. These embodiments are for illustrative purposes only, and the present invention is not limited to these embodiments.

[0098] Example 1

[0099] 1. Preparation of catalysts for the oxygen evolution reaction

[0100] 1 g of SnO2 powder was mixed with a solution obtained by dissolving 0.3 g of iridium chloride hydrate in 0.5 mL of ethanol and dried at 60 °C to obtain a dried product. The dried product was then mixed with 5 g of the fluorine precursor NH4F, with the molar ratio of SnO2 to NH4F designed to be 1:20, and homogenized to reduce the powder particle size to below 150 μm, thus obtaining a mixture. Here, the amount of fluorine doping can be adjusted by regulating the amounts of the fluorine precursor and the dried product. The prepared mixture was heat-treated at 400 °C for 6 hours under an inert or reducing gas atmosphere. After washing with ethanol and distilled water and filtering the heat-treated powder, it was dried at 60 °C for 12 hours to prepare a catalyst for the oxygen evolution reaction in a water electrolysis cell.

[0101] 2. Fabrication of a membrane electrode assembly containing a catalyst for the oxygen evolution reaction.

[0102] The prepared catalyst for the oxygen evolution reaction in a water electrolysis cell is mixed with an ionomer solution to achieve an ionomer / catalyst ratio of 0.3. The mixed catalyst slurry is dispersed and stirred for 24 hours to prepare a catalyst composition for the oxygen evolution reaction. This catalyst composition for the oxygen evolution reaction is referred to as the first catalyst composition.

[0103] A catalyst with a platinum particle content of 46% by weight on a graphite support is mixed with an ionomer solution to achieve an ionomer / carbon ratio of 1.0, thereby producing a second catalyst composition. The first catalyst composition is then thinly coated onto a transfer substrate using spraying, decal application, or ultrasonic spraying to produce a first electrode. After coating the second catalyst composition onto the transfer substrate to produce a second electrode, the first electrode is transferred to one side of a polymer electrolyte membrane, and the second electrode is transferred to the opposite side, and then bonded together to form a membrane electrode assembly.

[0104] Example 2

[0105] In manufacturing the catalyst for the oxygen evolution reaction, 1.5 g of fluorine precursor NH4F was used to design the molar ratio of SnO2 to NH4F to be 1:6. Apart from this, the catalyst and membrane electrode assembly for the oxygen evolution reaction were manufactured using substantially the same method as in Example 1.

[0106] Example 3

[0107] In manufacturing the catalyst for the oxygen evolution reaction, 0.15 g of the fluorine precursor NH4F was used to design the molar ratio of SnO2 to NH4F to be 1:1. Apart from this, the catalyst and membrane electrode assembly for the oxygen evolution reaction were manufactured using substantially the same method as in Example 1.

[0108] Comparative Example 1

[0109] 1.28g of tetradecylamine (C 14 H 31 95% of fluorine-doped SnO2 powder was dissolved in 22.5 mL of an aqueous ethanol solution (ethanol:water = 1:2.5), and then 20 mL of an ethanol solution containing 4.8 g of tin tetrachloride (SnCl4) and 0.48 g of ammonium fluoride (NH4F, as a fluorine precursor) was added. The mixture was stirred for 1 hour. Next, the mixture was mixed with 200 mL of a 1.5 mM ammonia solution and refluxed at 80 °C for 72 hours. The powder was then washed by centrifugation and dried using either hot drying or freeze drying. The dried powder was then heat-treated in air at 400 °C for 3 hours to obtain fluorine-doped SnO2 powder.

[0110] 1 g of the prepared fluorine-doped SnO2 powder was dispersed in a solution obtained by dissolving 0.074 g of iridium acetate (Ir(CH3COO)3) and 0.08 g of sodium hydroxide in 20 mL of ethylene glycol. The mixture was then reacted at 160 °C for 1 hour under an inert gas atmosphere and cooled. After washing by centrifugation, the powder was dried by hot drying or freeze drying to prepare the final catalyst.

[0111] Comparative Example 2

[0112] 1 g of SnO2 powder was dispersed in 22.5 mL of an aqueous ethanol solution (ethanol:water = 1:2.5), and then 20 mL of ethanol containing 0.48 g of NH4F as a fluorine precursor was added. After mixing for 1 hour, the mixture was refluxed at 80 °C for 72 hours. The mixture was then washed by centrifugation and dried using either hot drying or freeze drying. The dried powder was then heat-treated in air at 400 °C for 3 hours to obtain fluorine-doped SnO2 powder.

[0113] 1 g of the prepared fluorine-doped SnO2 powder was dispersed in a solution obtained by dissolving 0.074 g of iridium acetate (Ir(CH3COO)3) and 0.08 g of sodium hydroxide in 20 mL of ethylene glycol. The mixture was then reacted at 160 °C for 1 hour under an inert gas atmosphere and cooled. After washing by centrifugation, the powder was dried by hot drying or freeze drying to prepare the final catalyst.

[0114] Evaluation Example 1: Fluorine Content Analysis

[0115] To confirm the fluorine content of the fluorine-doped metal oxides in the supports manufactured in the examples and comparative examples, the percentage of fluorine atoms in the total fluorine-doped metal oxides was determined by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDS), and the results are shown in Table 1.

[0116] Next, in order to confirm the fluorine content of the fluorine-doped noble metal oxides in the water electrolysis catalyst particles manufactured in the examples and comparative examples, the percentage of fluorine atoms in the total fluorine-doped noble metal oxides was determined by high-resolution transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDS), and the results are shown in Table 1.

[0117] Table 1

[0118] Referring to Table 1, it can be confirmed that when SnO2 and IrO synthesized according to Examples 1 to 3 are... x When the mixture is fluorinated using a one-pot method, the fluorine doping level can be adjusted. Conversely, fluorine doping is performed during SnO2 synthesis and IrO... x Comparative Example 1, with fluorine-doped SnO2 loaded on it, and IrO2 loaded on synthesized SnO2. x In Comparative Example 2, where the load was on fluorine-doped SnO2, fluorine doping could not be successfully performed.

[0119] To confirm the IrO produced by the one-pot method in Example 1 xThe structure of IrO was analyzed using scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS). x / FTO was observed, and the results were as follows Figures 2 to 5 As shown.

[0120] refer to Figures 2 to 5 IrO x STEM images and energy-dispersive X-ray spectroscopy (EDS) mapping analysis of / FTO confirmed that fluorine was uniformly distributed in IrO through a one-pot process. x In FTO, it was also confirmed that the Ir catalyst was well supported on tin oxide (Sn).

[0121] Evaluation Example 2: Conductivity Evaluation

[0122] The first electrode manufactured in the examples and comparative examples was cut into 2cm×2cm pieces, and silver sheets were used to make electrodes at the two corners. The surface resistance was measured using the van der Burg surface resistance measurement method to evaluate the conductivity. The results are shown in Table 2.

[0123] Table 2

[0124] Referring to Table 2, it can be confirmed that when SnO2 and IrO synthesized according to Examples 1 to 3 are subjected to specific reactions... x When the mixture is fluorinated using a one-pot method, its conductivity is better than that of fluorinated doping during SnO2 synthesis and IrO. x Comparative Example 1, with fluorine-doped SnO2 loaded on it, and IrO2 loaded on synthesized SnO2. x Comparative Example 2, loaded on fluorine-doped SnO2.

[0125] Evaluation Example 3: Evaluation of Water Electrolysis Performance

[0126] Distilled water was supplied to the membrane electrode assemblies manufactured in the examples and comparative examples at a flow rate of 5 ml / min at 80°C, and the water electrolysis performance was evaluated using the following procedure: current and resistance were measured at a rate of 10 mV / s up to 2 V using a linear scanning potentiometry method. The results are as follows: Figure 6 As shown.

[0127] refer to Figure 6 It can be confirmed that Examples 1 and 3, where the fluorine doping process proceeded smoothly, exhibited improved water electrolysis performance compared to Comparative Examples 1 and 2, where the fluorine doping process did not proceed smoothly. Furthermore, it can be confirmed that with increasing fluorine doping concentration, the water electrolysis performance of Example 1 is superior to that of Example 3.

[0128] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art using the basic concepts defined in the appended claims are also within the scope of the present invention.

Claims

1. A catalyst for the oxygen evolution reaction in a water electrolysis cell, comprising: The support contains fluorine-doped metal oxides; and Water electrolysis catalyst particles are located on the surface of the support and contain fluorine-doped noble metals or fluorine-doped noble metal oxides. The fluorine content in the entire fluorine-doped metal oxide, as determined by high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy, is between 1 at% and 20 at% of the total composition, and the fluorine content in the entire fluorine-doped noble metal or fluorine-doped noble metal oxide, as determined by high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy, is between 1 at% and 20 at% of the total composition.

2. The catalyst for the oxygen evolution reaction in a water electrolysis cell according to claim 1, wherein, The metal oxides include tungsten oxide, titanium oxide, nickel oxide, ruthenium oxide, tantalum oxide, tin oxide, cobalt oxide, or combinations thereof.

3. The catalyst for the oxygen evolution reaction in a water electrolysis cell according to claim 1, wherein, The metal oxide is a tin oxide.

4. The catalyst for the oxygen evolution reaction in a water electrolysis cell according to claim 1, wherein, The carrier is spherical, linear, or rod-shaped.

5. The catalyst for the oxygen evolution reaction in a water electrolysis cell according to claim 1, wherein, The carrier has the morphology of secondary particles formed by the aggregation of primary particles. The average particle size D of the primary particles 50 The range is from 0.005 μm to 0.5 μm. The average particle size D of the secondary particles 50 The range is from 0.05 μm to 1.0 μm.

6. The catalyst for the oxygen evolution reaction in a water electrolysis cell according to claim 1, wherein, The content of the support is 20% to 80% by weight relative to a total of 100% by weight of the support and water electrolysis catalyst particles.

7. The catalyst for the oxygen evolution reaction in a water electrolysis cell according to claim 1, wherein, The noble metal oxide is IrO. x , where x is an integer from 1 to 3.

8. The catalyst for the oxygen evolution reaction in a water electrolysis cell according to claim 1, wherein, The average particle size D of the water electrolysis catalyst particles 50 The range is from 0.001 μm to 0.015 μm.

9. An oxygen evolution electrode, comprising: The catalyst for oxygen evolution reaction in a water electrolysis cell as described in claim 1.

10. A method for manufacturing an oxygen evolution electrode, comprising: (i) The step of mixing a metal oxide into a solution containing a noble metal oxide precursor and then drying it to produce a dried product; (ii) The step of mixing the dried material with a fluorine precursor and then subjecting it to heat treatment to produce a catalyst for the oxygen evolution reaction in a water electrolysis cell; (iii) The step of mixing the catalyst used for the oxygen evolution reaction in a water electrolysis cell with an ionomer to prepare a slurry; and (iv) The step of dispersing the slurry.

11. The method for manufacturing an oxygen evolution electrode according to claim 10, wherein, The noble metal oxide precursors include IrCl3, IrCl3 hydrate, IrCl4, H2Cl6Ir, Ir(CH3COO)3, or combinations thereof.

12. The method for manufacturing an oxygen evolution electrode according to claim 10, wherein, The fluorine precursor includes NH4F, NH4HF2, or a combination thereof.

13. The method for manufacturing an oxygen evolution electrode according to claim 10, wherein, In step (ii), the molar ratio of the dried material to the fluorine precursor is 1:1 to 1:

30.

14. A membrane electrode assembly for a water electrolysis cell, comprising: Polymer electrolyte membrane; The oxygen evolution electrode of claim 9 is located on one side surface of the polymer electrolyte membrane; as well as The hydrogen evolution electrode is located on the other side surface of the polymer electrolyte membrane.

15. A water electrolysis cell, comprising: The membrane electrode assembly for a water electrolyzer as described in claim 14.

Images