Catalytic electrode, method for manufacturing a catalytic electrode, and film electrode assembly

Abstract

To provide a catalyst electrode, a method for manufacturing a catalyst electrode, and a membrane electrode assembly.SOLUTION: A catalyst electrode according to an embodiment of the present disclosure includes: a metal layer; and a catalyst layer formed on the metal layer, wherein the catalyst layer includes silver and iridium.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments of this disclosure relate to a catalytic electrode, a method for manufacturing a catalytic electrode, and a film electrode assembly. [Background technology]

[0002] Hydrogen energy is a clean energy source and is attracting attention as one of the promising alternative energy sources for solving energy problems in the long term. Among hydrogen production methods, water electrolysis, which uses electrical energy to separate water into hydrogen and oxygen and does not emit carbon dioxide, is environmentally friendly and is attracting a lot of attention, and is expected to make a significant contribution to achieving carbon neutrality.

[0003] On the other hand, the electrolysis reaction of water consists of an oxygen evolution reaction (OER) and a hydrogen evolution reaction (HER), and the oxygen evolution reaction and the hydrogen evolution reaction are as shown in Chemical Formula 1 below. Here, OER is produced at the oxygen evolution electrode, and HER is produced at the hydrogen evolution electrode.

[0004] [C1] Oxygen evolution reaction: 2H2O → 4H + +O2+4e - Hydrogen evolution reaction: 4H + +4e - →2H2 Overall reaction: 2H2O → 2H2 + O2

[0005] In particular, in the above water electrolysis reaction, the slower reaction rate of the oxygen evolution reaction compared to the hydrogen evolution reaction generates an overpotential higher than the theoretical oxygen evolution reaction voltage. Therefore, in order to improve the performance of water electrolysis systems, it is necessary to develop highly efficient catalysts that reduce the reaction overpotential of the oxygen evolution reaction, which requires a large amount of overpotential. [Overview of the project] [Problems that the invention aims to solve]

[0006] The embodiments of this disclosure can provide a catalyst electrode with improved performance in the oxygen evolution reaction, a method for manufacturing the catalyst electrode, and a membrane electrode assembly. [Means for solving the problem]

[0007] The catalyst electrode according to the embodiments of this disclosure comprises a metal layer and a catalyst layer formed on the metal layer, wherein the catalyst layer contains silver and iridium.

[0008] In one embodiment, the catalyst electrode contains 0.02 mg / cm³ of catalyst in the catalyst layer. 2 ~0.8 mg / cm³ 2 It contains iridium in the following supported amounts.

[0009] In one embodiment, at least a portion of the silver and iridium contained in the catalyst layer can be chemically bonded to each other.

[0010] In one embodiment, the metal layer may include one or more selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fibers.

[0011] In one embodiment, the metal layer may contain one or more metals or metal alloys selected from the group consisting of titanium, nickel, and stainless steel.

[0012] In one embodiment, the catalyst layer may include a first layer containing silver and in contact with the metal layer, and a second layer containing iridium and formed on the first layer.

[0013] In one embodiment, at least a portion of the silver contained in the first layer can be chemically bonded with the metal of the metal layer.

[0014] In one embodiment, the catalyst layer does not need to contain a binder.

[0015] The method for manufacturing a catalyst electrode according to the embodiments of this disclosure includes the step of coating a metal substrate with silver and iridium.

[0016] In one embodiment, the step of coating the metal substrate with silver and iridium may include the steps of forming a first layer containing silver on the metal substrate by immersing the metal substrate in a silver precursor solution containing silver ions, and forming a second layer containing iridium on the first layer by immersing the metal substrate with the first layer formed on it in an iridium precursor solution containing iridium ions.

[0017] In one embodiment, the step of forming the first layer may include the step of heat-treating the substrate coated with the first layer.

[0018] In one embodiment, the process of heat-treating the substrate coated with the first layer is carried out at a temperature of 100°C to 900°C for 10 minutes to 10 hours.

[0019] In one embodiment, the step of forming the second layer may include the step of heat-treating the substrate coated with the second layer.

[0020] In one embodiment, the process of heat-treating the substrate coated with the second layer is carried out at a temperature of 100°C to 900°C for 10 minutes to 10 hours.

[0021] In one embodiment, the method for manufacturing the catalyst electrode may further include a step of acid-treating the metal substrate before the step of coating the metal substrate with silver and iridium.

[0022] In one embodiment, the silver precursor solution contains one or more silver precursors selected from the group consisting of silver nitrate, silver acetate, silver sulfate, silver perchlorate, silver acetylacetonate, and silver methanesulfonate, and / or the iridium precursor solution contains one or more iridium precursors selected from the group consisting of iridium chloride, iridium chloride hydrate, iridium bromide, iridium acetylacetonate, hexachloroiridic acid, sodium hexachloroiridate, and potassium hexachloroiridate, preferably containing iridium chloride hydrate.

[0023] The membrane electrode assembly according to an embodiment of the present disclosure includes an electrolyte membrane, an anode located on one side of the electrolyte membrane, and a cathode located on the other side of the electrolyte membrane. The anode includes a metal layer and a catalyst layer formed on the metal layer and containing silver and iridium.

[0024] The present invention further provides the use of a catalytic electrode for incorporation into a water electrolysis device or a fuel cell.

[0025] According to the present disclosure, a catalytic electrode with improved OER performance, a method for manufacturing the catalytic electrode, and a membrane electrode assembly can be provided.

Advantages of the Invention

[0026] According to the present disclosure, a catalytic electrode with improved oxygen evolution reaction performance, a method for manufacturing the catalytic electrode, and a membrane electrode assembly can be provided.

Brief Description of the Drawings

[0027] [[ID=~26]] [Figure 1] It is a diagram for explaining a catalytic electrode according to an embodiment of the present disclosure. [Figure 2] It is a flowchart for explaining a method for manufacturing a catalytic electrode according to an embodiment of the present disclosure. [Figure 3] It is a diagram for explaining the operation S110 in FIG. 2 in more detail. <~ [Figure 4] It is a diagram for explaining the operation S120 in FIG. 2 in more detail. [Figure 5] This figure illustrates the catalytic electrode manufactured by the catalytic electrode manufacturing method shown in Figure 2. [Figure 6] This is an EDS (Energy Dispersive Spectrometer) mapping image of a catalyst electrode according to one embodiment of the present disclosure. [Figure 7] This graph shows the results of XRD (X-Ray Diffraction) analysis of catalyst electrodes according to one embodiment and a comparative example of this disclosure. [Figure 8] This graph shows the results of XPS (X-ray Photoelectron Spectroscopy) analysis of catalyst electrodes according to one example and a comparative example of this disclosure. [Figure 9] This graph shows the amount of iridium metal supported on catalyst electrodes according to one example and a comparative example of this disclosure, as measured by ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy) analysis. [Figure 10] This graph shows the performance of the oxygen evolution reaction of a catalyst electrode according to one embodiment and a comparative example of the present disclosure. [Modes for carrying out the invention]

[0028] The structural or functional descriptions of the embodiments disclosed herein or in the application are illustrative only for the purpose of illustrating embodiments of the technical idea of ​​the present invention, and embodiments of the technical idea of ​​the present invention can be carried out in various forms other than those disclosed herein or in the application, and the technical idea of ​​the present invention should not be construed as being limited to the embodiments described herein or in the application.

[0029] The present invention will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that such embodiments described with reference to the accompanying drawings are provided for further understanding of the spirit of the invention and do not limit the subject matter disclosed in the detailed description and the appended claims. Furthermore, throughout this disclosure, unless otherwise specified, the terms “contains,” “includes,” “contains,” or “has” do not mean the exclusion of other components, but rather the inclusion of other components, and do not exclude any elements, materials, or processes not further listed. Unless the context explicitly indicates otherwise, the singular form of a term used herein may be interpreted as including the plural form. Where used herein, the singular forms of “a,” “an,” and “the” include multiple referents unless the context explicitly indicates otherwise. The numerical ranges used in this disclosure include all values ​​within a range, including the lower and upper limits, increments that are logically derived in a certain form and extend within a defined range, all double limits, and all possible combinations of upper and lower limits within a numerical range defined in a different form. For example, if the content of a composition is defined as 10% to 80% or 20% to 50%, then the numerical ranges of 10% to 50% or 50% to 80% should also be interpreted as being included in the specification of this disclosure. Unless otherwise defined in this disclosure, values ​​that may fall outside a numerical range due to experimental error or truncation are also included in the defined numerical range. For the purposes of this disclosure, unless otherwise specifically indicated, all numerical values ​​representing quantities of components, reaction conditions, dimensions, physical properties, etc., used in this disclosure should be understood in all cases to be modified by the term “approximately.” Hereinafter, unless otherwise specifically defined in this disclosure, “approximately” is considered to be a value within 30%, 25%, 20%, 15%, 10%, 5%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise indicated, the numerical parameters described in this disclosure are approximations that may vary depending on the desired properties to be obtained by the invention. Although the numerical ranges and parameters describing the broad scope of this invention are approximations, the numerical values ​​described in specific examples are reported as accurately as possible. However, any numerical value inherently contains a certain degree of error that inevitably arises from the standard deviation observed in each test measurement.

[0030] catalyst electrode

[0031] One aspect of this disclosure provides a catalytic electrode comprising a metal layer and a catalyst layer formed on the metal layer, wherein the catalyst layer comprises silver and iridium.

[0032] Figure 1 is a diagram illustrating a catalyst electrode according to one embodiment of the present disclosure. Hereinafter, the catalyst electrode according to an embodiment of the present disclosure will be described with reference to Figure 1.

[0033] Referring to Figure 1, the catalyst electrode 100 includes a metal layer 10 and a catalyst layer 20.

[0034] The metal layer 10 contains a catalyst metal deposition It can function as a substrate, and in one embodiment, the metal layer 10 may include one or more selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fiber. In another embodiment, the metal layer 10 may also include one or more metals selected from the group consisting of titanium, nickel, and stainless steel. For example, the metal layer may include, but is not limited to, titanium mesh.

[0035] The catalyst layer 20 is formed on the metal layer 10 and contains silver and iridium. The catalyst layer 20 may contain silver and iridium in a single layer, or, as will be described later, silver and iridium may be contained in separate layers. In the embodiment, the metal layer 10 may be coated with silver first, and then coated with iridium. In one embodiment, the catalyst layer 20 may include a first layer containing silver and in contact with the metal layer 10, and a second layer containing iridium and formed on the first layer. In one embodiment, at least a portion of the silver contained in the first layer can be chemically bonded with the metal of the metal layer, thereby improving the electron transfer performance and durability of the catalyst electrode 100. The chemical bond between the silver and the metal of the metal layer may be a metallic bond.

[0036] In the embodiment, at least a portion of the silver and iridium contained in the catalyst layer 20 can be chemically bonded to each other. The chemical bond between silver and iridium may be a metallic bond. That is, by chemically bonding at least a portion of the silver and iridium contained in the catalyst layer 20 to each other, the electronic structure of at least a portion of the silver and iridium contained in the catalyst layer 20 can be altered. By altering the electronic structure of at least a portion of the silver and iridium contained in the catalyst layer 20, in particular by altering the electronic structure of at least a portion of the iridium contained in the catalyst layer 20, the activity of the catalyst electrode 100 for the oxygen evolution reaction can be improved, and as a result, the oxygen evolution performance of the catalyst electrode 100 can be improved.

[0037] In the examples, the catalyst layer 20 does not need to contain a binder. Silver and iridium may be directly coated onto the metal layer 10, and a chemical bond can be formed between the metal layer 10 and the catalyst layer 20, so the catalyst layer 20 can be formed on the metal layer 10 without using another binder.

[0038] The commonly used Nafion binder is a PFAS (perfluoroalkyl compound), which can cause environmental problems. Furthermore, the Nafion binder degrades during the electrode reaction, leading to decreased activity and reduced durability. In addition, since the catalyst layer can be directly deposited on the current collector (metal layer) without using a binder, the chemical bond between the current collector (metal layer) and the catalyst layer increases, improving electron transfer and durability.

[0039] The catalyst electrode 100 according to the embodiments of this disclosure can have oxygen evolution performance equivalent to or even better than that of conventionally used precious metal catalyst electrodes, even with a smaller amount of metal loading compared to conventionally used precious metal catalyst electrodes.

[0040] The catalyst electrode 100 according to the embodiments of this disclosure may be included in a water splitting apparatus or a fuel cell, but the applications of the catalyst electrode 100 are not limited thereto.

[0041] Method for manufacturing catalyst electrodes

[0042] In other aspects of this disclosure, a method for manufacturing a catalyst electrode is provided, which includes the step of coating a metal substrate with silver and iridium.

[0043] Figure 2 is a flowchart illustrating a method for manufacturing a catalyst electrode according to one embodiment of the present disclosure. The method for manufacturing a catalyst electrode according to an embodiment of the present disclosure will be described below with reference to Figure 2.

[0044] A method for manufacturing a catalyst electrode according to other aspects of this disclosure includes a step of coating a metal substrate with silver and iridium. Furthermore, a method for manufacturing a catalyst electrode according to other aspects of this disclosure may further include a step of acid-treating the metal substrate before the step of coating the metal substrate with silver and iridium. The metal substrate may have the same configuration as the metal layer described above. For this reason, in one embodiment, the metal substrate may include one or more selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fibers, and in one embodiment, the metal substrate may include one or more metals selected from the group consisting of titanium, nickel, and stainless steel.

[0045] Referring to Figure 2, the step of coating a metal substrate with silver and iridium may include the step of forming a first layer containing silver on the metal substrate (S110 operation) and the step of forming a second layer containing iridium on the first layer (S120 operation).

[0046] The S110 operation can be performed by immersing the metal substrate 10 in a silver precursor solution 200 containing silver ions (Figure 3). That is, the S110 operation can be performed by dip coating. This allows for uniform coating of silver, which has a high ionization energy, onto the metal substrate. In one embodiment, the silver precursor solution may contain a silver salt. For example, the silver precursor solution may contain one or more selected from the group consisting of silver nitrate, silver acetate, silver sulfate, silver perchlorate, silver acetylacetonate, and silver methanesulfonate, but is not limited thereto. Also, in one embodiment, the silver precursor solution may contain water, ethanol, etc. as a solvent, but is not limited to the specific example. deposition From an efficiency standpoint, a mixed solvent of water and ethanol can also be used.

[0047] The S110 operation may further include a step of heat-treating the substrate coated with the first layer. The heat-treating step can be performed at a temperature of 100°C to 900°C for 10 minutes to 10 hours. This allows the silver in the first layer coated on the metal substrate to have a stable metallic phase and removes impurities from the metal substrate.

[0048] The S120 operation can be performed by immersing a metal substrate 10 on which the first layer 21 has been formed into an iridium precursor solution 300 containing iridium ions (Figure 4). That is, the S120 operation can be performed by dip coating. In one embodiment, the iridium precursor solution may contain an iridium salt. For example, the iridium precursor solution may contain one or more selected from the group consisting of iridium chloride, iridium chloride hydrate, iridium bromide, iridium acetylacetonate, hexachloroyridic acid, sodium hexachloroyridate, and potassium hexachloroyridate, but is not limited thereto. Also, in one embodiment, the iridium precursor solution may contain water, ethanol, etc. as a solvent, but is not limited to the specific example. deposition From an efficiency standpoint, a mixed solvent of water and ethanol can also be used.

[0049] The S120 operation may further include a step of heat-treating the substrate coated with the second layer. The heat-treating step can be carried out at a temperature of 100°C to 900°C for 10 minutes to 10 hours. This allows the iridium in the second layer coated on the first layer to have a stable metallic phase.

[0050] As a result, a catalyst electrode 100 can be manufactured in which a catalyst layer 20 including a first layer 21 and a second layer 22 is formed on a metal layer 10, as shown in Figure 5. By forming the first layer 21 on the metal layer 10 first in this way, oxidation of the metal of the metal substrate during the water electrolysis reaction can be minimized.

[0051] membrane electrode assembly

[0052] In yet another aspect of the present disclosure, a membrane electrode assembly is provided, comprising an electrolyte membrane, an anode located on one side of the electrolyte membrane, and a cathode located on the other side of the electrolyte membrane, wherein the anode comprises a metal layer and a catalyst layer formed on the metal layer, the catalyst layer comprising silver and iridium.

[0053] A film electrode assembly provided in yet other aspects of this disclosure may include the catalyst electrode described above as an anode. That is, the anode may include a metal layer and a catalyst layer formed on the metal layer and containing silver and iridium.

[0054] Furthermore, the film electrode assemblies provided in other aspects of this disclosure may include a cathode containing a cathode catalyst, which may be a substance commonly used in the industry. For example, the cathode catalyst may be, but is not limited to, one single substance or a mixture of two or more substances selected from the group consisting of platinum, ruthenium, iridium, osmium, palladium, platinum-ruthenium alloys, platinum-osmium alloys, platinum-palladium alloys, and oxides thereof.

[0055] Furthermore, the membrane electrode assemblies provided in other aspects of this disclosure may include an electrolyte membrane positioned between the anode and cathode, and the electrolyte membrane may, for example, be a polymer electrolyte membrane containing a fluorine-based polymer or a hydrocarbon-based polymer, but is not limited thereto.

[0056] The membrane electrode assemblies provided in other aspects of this disclosure may be included in a water electrolyzer or a fuel cell.

[0057] Examples

[0058] The catalyst electrode, method for manufacturing the catalyst electrode, and film electrode assembly according to this disclosure will be described in more detail below based on examples and comparative examples. However, the following examples and comparative examples are merely illustrative to illustrate this disclosure in more detail, and this disclosure is not limited to the following examples and comparative examples.

[0059] <Example 1> - Fabrication of Ir-Ag / Ti electrodes

[0060] A 100 mM silver precursor solution was prepared by adding silver nitrate (Sigma) to a mixed solution of distilled water and ethanol (volume ratio 1:1), and then sonicating and stirring until completely dissolved.

[0061] The silver precursor solution prepared in this manner was dipped into a titanium mesh treated with oxalic acid (10 wt%) to perform a dip coating. This process was then repeated three times, followed by drying on a hot plate at 80°C. Subsequently, a silver-coated titanium electrode was produced through a heat treatment process at 300°C for 1 hour.

[0062] Furthermore, iridium chloride hydrate (Sigma) was added to a mixed solvent of distilled water / ethanol (volume ratio 1:1), and then sonicated and stirred until completely dissolved to prepare a 6.7 mM iridium precursor solution.

[0063] The iridium precursor solution prepared in this manner was used to dip-coate a silver-coated titanium electrode, followed by drying on a hot plate at 80°C. This process was repeated three times. Subsequently, a silver and iridium-coated Ir-Ag / Ti electrode was produced through a heat treatment process at 300°C for one hour.

[0064] <Comparative Example 1> - Preparation of Ir / Ti electrodes

[0065] The electrodes were manufactured in the same manner as in Example 1, except that the step of adding the titanium mesh to the silver precursor solution was omitted.

[0066] <Comparative Example 2> - Preparation of Ag / Ti electrode

[0067] The electrodes were manufactured in the same manner as in Example 1, except that the step of adding the titanium mesh to the iridium precursor solution was omitted.

[0068] <Comparative Example 3> - Preparation of IrO2 electrode

[0069] We prepared IrO2black (100% by weight, Alfa Aesar), a commonly used oxidation electrode catalyst.

[0070] <Experimental Example 1> - Morphological analysis of the electrode in Example 1

[0071] Using a scanning electron microscope (Apreo) equipped with an EDS detector, EDS mapping analysis results for the electrode in Example 1 were obtained and are shown in Figure 6.

[0072] Referring to Figure 6, it can be confirmed that iridium and silver are simultaneously present on the titanium mesh of the electrode in Example 1, and that both iridium and silver are uniformly distributed throughout the entire titanium mesh. deposition It can be confirmed that it is being done.

[0073] <Experimental Example 2> - Electrode-internal catalyst layer deposition Analysis of characteristics

[0074] The metal crystal planes of the electrodes in Example 1, Comparative Example 1, and Comparative Example 2 were confirmed using X-ray diffraction (XRD; PANalytical). Measurements were taken using Cu Kα radiation at 40 kV and 100 mA, with a scanning speed of 6° per minute at 0.01° intervals, covering a range of 10 to 80°. The results are shown in Figure 7.

[0075] Referring to Figure 7, the XRD analysis results for the electrode of Comparative Example 1 showed an iridium peak, while the XRD analysis results for the electrode of Comparative Example 2 showed a silver peak. On the other hand, in the electrode of Example 1, only a peak for silver was observed, and the iridium peak was very small and difficult to observe. However, combining the analysis results from Experimental Example 1 and the XRD analysis results from Experimental Example 2, it can be seen that the iridium peak is difficult to observe during XRD analysis because it is distributed evenly at a very small size.

[0076] Furthermore, the electronic structure of the metal present on the electrode surface of the electrodes in Example 1 and Comparative Example 1 was confirmed by X-ray photoelectron spectroscopy (XPS), and the results are shown in Figure 8.

[0077] Referring to Figure 8, when examining the iridium main peaks of the electrode in Example 1 and the electrode in Comparative Example 1, the peak in Example 1 is shifted to the right compared to the peak in Comparative Example 1. This suggests that in addition to iridium, silver is also present in the catalyst layer of the electrode in Example 1, indicating that the presence of silver altered the electronic structure of the iridium.

[0078] Furthermore, the iridium content (wt%) in the catalyst layer of electrodes manufactured using inductively coupled plasma atomic emission spectroscopy (ICP-AES, NexION 300X) for the electrodes of Example 1 and Comparative Example 3 was determined, and the results are shown in Figure 10.

[0079] Referring to FIG. 9, the content of iridium present in the catalyst layer of the electrode of Example 1 is 0.1 mg / cm 2 level, compared with the electrode of Comparative Example 3 having an iridium content of 1.7 mg / cm 2 level, it can be confirmed that the loading amount of iridium as the active metal is significantly lower. Despite the significantly low iridium loading amount of the electrode of Example 1, it can have rather excellent activity compared with the electrode of Comparative Example 3 as described later.

[0080] <Experimental Example 3> - Evaluation of Electrochemical Characteristics of Electrodes

[0081] The electrodes of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were used as the working electrode, Ag / AgCl (sat. 3M KCl) was used as the reference electrode, and a graphite rod was used as the counter electrode to measure the polarization of the oxygen evolution reaction for the electrodes of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Each electrode was immersed in a 0.5M H2SO4 acidic solution, and the oxygen evolution reaction was carried out at a scan rate of 10 mV / s and room temperature conditions.

[0082] The polarization results for the oxygen evolution reaction are shown in FIG. 10 and Table 1 below. At this time, all measured values were expressed as "vs RHE (reversible hydrogen electrode)".

[0083]

Table 1

[0084] Referring to FIG. 10 and Table 1, it can be seen that the performance of the reference oxygen evolution reaction is excellent in terms of activity in the order of Example 1, Comparative Example 3, Comparative Example 1, and Comparative Example 2. -2

[0085] Example 1 is 10 mAcm -2 ​To obtain the corresponding current density value, an overvoltage of only 287mV was required, which is 15mV smaller than that of Comparative Example 3 and 53mV smaller than that of Comparative Example 1.

[0086] As confirmed by the ICP analysis results of Example 1 described above, Example 1 has a significantly lower catalyst metal loading amount compared to Comparative Example 3, yet its oxygen evolution performance is superior to that of Comparative Example 3.

[0087] In other words, the electrode of Example 1 has iridium and silver simultaneously on a titanium mesh. deposition Therefore, it can be expected that the oxygen evolution performance is significantly improved because the electronic structure of iridium, an active metal, is altered by the interaction between the two.

Claims

1. Metal layer, The catalyst layer formed on the metal layer comprises, The catalyst layer is Contains silver and iridium, The catalyst layer is A first layer containing the aforementioned silver and in contact with the aforementioned metal layer, A second layer comprising the iridium and formed on the first layer, The iridium contained in the second layer has a metallic phase and is a catalytic electrode for an oxygen evolution reaction.

2. At least a portion of the silver and iridium contained in the catalyst layer, A catalyst electrode according to claim 1, which is chemically bonded to each other.

3. A catalyst electrode according to claim 1, wherein the catalyst layer contains 0.02 to 0.8 mg / cm³ of iridium ２ A catalyst electrode characterized by containing a supported amount.

4. The aforementioned metal layer is The catalyst electrode according to claim 1, comprising one or more selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fibers.

5. The aforementioned metal layer is The catalyst electrode according to claim 4, comprising one or more metals selected from the group consisting of titanium, nickel, and stainless steel.

6. At least a portion of the silver contained in the first layer is The catalyst electrode according to claim 1, which is chemically bonded to the metal of the metal layer.

7. The catalyst layer is A catalyst electrode according to claim 1, which does not contain a binder.

8. The process includes the step of coating a metal substrate with silver and iridium. The step of coating the metal substrate with silver and iridium is as follows: The process involves immersing the metal substrate in a silver precursor solution containing silver ions to form a first layer containing silver on the metal substrate, A method for producing a catalyst electrode for an oxygen evolution reaction, comprising the steps of: immersing a metal substrate on which the first layer is formed in an iridium precursor solution containing iridium ions to form a second layer containing iridium in a metallic phase on the first layer.

9. The step of forming the first layer is, A method for manufacturing a catalyst electrode according to claim 8, comprising the step of heat-treating a substrate coated with the first layer.

10. The step of forming the aforementioned second layer is: A method for manufacturing a catalyst electrode according to claim 8, comprising the step of heat-treating a substrate coated with the second layer.

11. Before the step of coating the metal substrate with silver and iridium, A method for manufacturing a catalyst electrode according to any one of claims 8 to 10, further comprising the step of treating the metal substrate with acid.

12. The method according to claim 8, wherein the silver precursor solution comprises at least one silver precursor selected from the group consisting of silver nitrate, silver acetate, silver sulfate, silver perchlorate, silver acetylacetonate, and silver methanesulfonate, and / or the iridium precursor solution comprises at least one iridium precursor selected from the group consisting of iridium chloride hydrate, iridium bromide, iridium acetylacetonate, hexachloroiridiic acid, sodium hexachloroiridiate, and potassium hexachloroiridiate.

13. Electrolyte membrane, an anode located on one surface of the electrolyte membrane, The electrolyte membrane includes a cathode located on the other side of the electrolyte membrane, The aforementioned anode is Metal layer, The catalyst layer formed on the aforementioned metal layer and containing silver and iridium, The catalyst layer is A first layer containing the aforementioned silver and in contact with the aforementioned metal layer, A second layer comprising the iridium and formed on the first layer, The iridium contained in the second layer has a metallic phase, forming a film electrode assembly for an oxygen evolution reaction.

14. Use of the catalytic electrode according to any one of claims 1 to 6 for incorporation into a water electrolysis device or fuel cell.

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