Water electrolysis electrode, method for manufacturing water electrolysis electrode, and water electrolysis apparatus

Abstract

The present invention provides a water electrolysis electrode with a low amount of precious metal support and excellent oxygen evolution reaction performance, as well as a water electrolysis apparatus containing the same. Furthermore, it provides a method for efficiently manufacturing water electrolysis electrodes. [Solution] A water electrolysis electrode according to one embodiment includes a metal layer and a catalyst layer formed on the metal layer, wherein the catalyst layer may contain silver, iridium, and ruthenium.

Description

[Technical Field]

[0001] This disclosure relates to a water electrolysis electrode, a method for manufacturing a water electrolysis electrode, and a water electrolysis apparatus. [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 the hydrogen production methods, the water electrolysis method, which uses electrical energy to separate water into hydrogen and oxygen, and thus does not emit carbon dioxide, is attracting a lot of attention because it is environmentally friendly and can make a big contribution to achieving carbon neutrality.

[0003] On the other hand, water electrolysis reactions include the oxygen evolution reaction (OER) that occurs at the oxygen evolution electrode of a water electrolysis system and the hydrogen evolution reaction that occurs at the hydrogen evolution electrode. In acidic and alkaline media, the half-cell reaction and the overall reaction can be represented by the following chemical formulas 1 and 2.

[0004] [Chemical formula 1] Oxygen evolution reaction: 2H₂O(l) → O₂(g) + 4H + + 4e - Hydrogen evolution reaction: 4H + + 4e - → 2H2(g) Total reaction: H2O(l) → H2(g) + 1 / 2O2(g) [Chemical formula 2] Oxygen evolution reaction: 2OH - → 1 / 2O2(g) + H2O(l) + 2e - Hydrogen evolution reaction: 2H2O(l) + 2e - →H2(g)+ 2OH - Total reaction: H2O(l) → H2(g) + 1 / 2O2(g)

[0005] On the other hand, in the aforementioned water electrolysis reaction, the reaction rate during oxygen evolution is slower than that during hydrogen evolution, which can lead to the generation of an overpotential higher than the theoretical oxygen evolution reaction voltage. To reduce this reaction overpotential and improve oxygen evolution performance and efficiency, catalysts for electrodes made of precious metals such as platinum and iridium, and electrodes using these catalysts, are primarily employed. However, the use of precious metal catalysts presents problems such as high costs and difficulty in adjusting supply and demand.

[0006] Therefore, there is a need to develop water electrolysis electrodes, specifically oxygen-evolving electrodes, that can replace or reduce the precious metal content of precious metal catalysts while simultaneously maintaining high oxygen evolution reaction performance. [Overview of the project] [Problems that the invention aims to solve]

[0007] According to one aspect of this disclosure, it is possible to provide a water electrolysis electrode with a small amount of precious metal supported and excellent oxygen evolution reaction performance, as well as a water electrolysis apparatus including the same.

[0008] According to other aspects of this disclosure, a method for manufacturing a water electrolytic electrode can be provided that can efficiently produce a water electrolytic electrode. [Means for solving the problem]

[0009] The water electrolysis electrode according to this disclosure comprises a metal layer and a catalyst layer formed on the metal layer, wherein the catalyst layer may contain silver, iridium, and ruthenium.

[0010] In one embodiment of a water electrolysis electrode, the metal layer may include at least one selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fibers.

[0011] In one embodiment of a water electrolysis electrode, the metal layer may include at least one selected from the group consisting of titanium, nickel, and stainless steel, or an alloy thereof.

[0012] In one embodiment of a water electrolysis electrode, the metal layer may include titanium felt.

[0013] In one embodiment of the water electrolysis electrode, at least some of the silver, iridium, and ruthenium contained in the catalyst layer can interact with each other electrically.

[0014] In a water electrolysis electrode according to 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 ruthenium and formed on the first layer.

[0015] In one embodiment of the water electrolysis electrode, at least a portion of the silver contained in the first layer can be chemically bonded with the metal elements of the metal layer.

[0016] In one embodiment of the water electrolysis electrode, the water electrolysis electrode may not contain a binder.

[0017] In one embodiment of the water electrolysis electrode, the water electrolysis electrode may contain iridium and ruthenium in a weight ratio of 9:1 to 5:5.

[0018] In one embodiment of the water electrolysis electrode, the iridium may be contained in an amount of 0.3 to 0.5% by weight based on the total weight of the water electrolysis electrode.

[0019] In one embodiment of the water electrolysis electrode, the water electrolysis electrode may contain ruthenium in an amount of 0.05 to 0.5% by weight based on the total weight of the water electrolysis electrode.

[0020] The method for manufacturing a water electrolysis electrode according to the present disclosure includes the step of forming a catalyst layer on a metal substrate, and the catalyst layer can include silver, iridium, and ruthenium.

[0021] In the method for manufacturing a water electrolysis electrode according to an embodiment, the metal substrate can include at least any one selected from the group consisting of a metal mesh, a metal foam, a metal foil, a metal felt, and metal fibers.

[0022] In the method for manufacturing a water electrolysis electrode according to an embodiment, the metal substrate can include at least any one selected from the group consisting of titanium, nickel, and stainless steel or an alloy thereof.

[0023] In the method for manufacturing a water electrolysis electrode according to an embodiment, the step of forming a catalyst layer on the metal substrate includes contacting the metal substrate with a first precursor solution containing silver ions to obtain a metal substrate having a first layer containing silver, and contacting the metal substrate having the first layer formed thereon with a second precursor solution containing iridium ions and ruthenium ions to form a second layer containing iridium and ruthenium on the first layer.

[0024] In the method for manufacturing a water electrolysis electrode according to an embodiment, the step of obtaining the metal substrate having the first layer formed thereon can include heat-treating the metal substrate having the first layer formed thereon.

[0025] In the method for manufacturing a water electrolysis electrode according to an embodiment, the step of forming the second layer can include heat-treating the metal substrate having the second layer formed thereon.

[0026] In the method for manufacturing a water electrolysis electrode according to an embodiment, before the step of forming a catalyst layer on the metal substrate, the method can further include the step of acid-treating the metal substrate.

[0027] In the method for producing a water electrolytic electrode according to one embodiment, the second precursor solution may contain iridium ions and ruthenium ions in a molar concentration ratio of 9:1 to 5:5.

[0028] A water electrolyzer according to this disclosure includes an anode, a cathode, and a membrane located between the anode and the cathode, wherein the anode includes a metal layer and a catalyst layer formed on the metal layer, and the catalyst layer may include silver, iridium, and ruthenium. [Effects of the Invention]

[0029] According to one aspect of this disclosure, it is possible to provide a water electrolysis electrode with a small amount of precious metal supported and excellent oxygen evolution reaction performance, as well as a water electrolysis apparatus including the same.

[0030] According to other aspects of this disclosure, a method for manufacturing a water electrolytic electrode can be provided that can efficiently produce a water electrolytic electrode. [Brief explanation of the drawing]

[0031] [Figure 1] This drawing shows an example of a cross-section of a water electrolysis electrode according to one embodiment of the present disclosure. [Figure 2] This drawing shows another example of a cross-section of a water electrolysis electrode according to one embodiment of the present disclosure. [Figure 3] This is a step-by-step diagram showing an example of a method for manufacturing a water electrolytic electrode according to one embodiment of the present disclosure. [Figure 4] This is an SEM / EDS mapping image of the electrode in Example 1. [Figure 5] This graph shows the XRD patterns of the electrodes for Example 1, Comparative Example 2, and Comparative Example 3. [Figure 6] This graph shows the XPS analysis results for the electrodes of Example 1 and Comparative Example 1. [Figure 7] This graph shows the XPS analysis results for the electrodes of Example 1 and Comparative Example 1. [Figure 8]This graph compares the amounts of iridium and ruthenium metal supported in the catalyst layers of the electrodes in Example 1 and Comparative Example 4, as determined by ICP mass spectrometry. [Figure 9] This is a diagram showing an example of a three-electrode system configured for electrochemical characterization. [Figure 10] This graph shows the current density vs. voltage curves evaluating the oxygen generation performance of each electrode in Examples 1 and 2 and Comparative Examples 1 to 4. [Figure 11] This graph shows the oxygen generation performance of the electrode in Example 1, evaluated for each cycle, represented by a current density vs. voltage curve. [Modes for carrying out the invention]

[0032] The embodiments described herein can be modified into various other forms, so the technology of one embodiment is not limited to the embodiments described below. Furthermore, throughout this specification, the terms “includes,” “equip,” “contains,” or “have” a component mean, unless otherwise stated, that other components may be included, rather than being excluded, and do not exclude any elements, materials, or processes not further listed.

[0033] In this specification, "identical" or "uniform" can mean, unless otherwise specified, being identical or uniform to one another within an acceptable margin of error. For example, when a certain configuration or physical property measurement is identical, it can include not only that the two objects being compared are completely identical, but also that they are identical within a margin of error. On the other hand, when a certain physical property measurement is identical, it can mean that the difference in measurements between the objects is approximately less than 5%, specifically less than 3%, and more specifically less than 1%.

[0034] Numerical ranges as used herein include lower and upper limits and all values ​​within those limits, increments logically derived from the shape and width of the defined range, all doubly limited values, and all possible combinations of upper and lower limits of numerical ranges limited to different shapes.

[0035] Unless otherwise defined herein, “approximately” can be considered to be a value within 30%, 25%, 20%, 15%, 10%, or 5% of the specified value.

[0036] In this specification, the use of terms such as "first," "second," and "third" preceding a component is intended to avoid confusion regarding the components being referred to, and is unrelated to any order, importance, or hierarchical relationship between the components. For example, an invention including only the second component without the first component is also possible.

[0037] In this specification, "contact" or "to come into contact" can mean direct physical or chemical contact between one object and another object, and can also mean, without limitation, contact between one object and another object through another object. On the other hand, it is preferable, but not limited to, that physical or chemical interaction between two objects is induced by the contact between one object and the other object.

[0038] As used herein, the term "salt" can mean, without limitation, the ionic form of a compound or chemical structure that includes a cation or anion to form an electrically neutral compound or structure.

[0039] As used herein, the term "water electrolysis" can mean, without limitation, a reaction or series of processes that use electrical energy to decompose water (H2O) into gaseous hydrogen (H2) and oxygen (O2).

[0040] The following is a detailed description of this disclosure. However, this is illustrative and not limited to the specific embodiments described herein.

[0041] water electrolysis electrode Figure 1 is a drawing showing an example of a cross-section of a water electrolysis electrode according to one embodiment of the present disclosure.

[0042] Referring to Figure 1, a water electrolysis electrode 100 according to one embodiment of the present disclosure includes a metal layer 10 and a catalyst layer 20 formed on the metal layer 10, wherein the catalyst layer 20 may contain silver (Ag), iridium (Ir), and ruthenium (Ru).

[0043] In one embodiment, the metal layer 10 can function as a substrate, support, or base on which a catalyst metal is deposited.

[0044] In one embodiment, the metal layer 10 may include at least one selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fibers.

[0045] In one embodiment, the metal layer 10 may include at least one selected from the group consisting of titanium, nickel, and stainless steel, or an alloy thereof.

[0046] In one embodiment, the metal layer 10 may include a titanium mesh or titanium felt. In a specific embodiment, the metal layer 10 may include titanium felt. In the case of titanium felt, the mechanical strength is higher than that of other forms of titanium-containing substrates, which can further improve the mechanical stability of the water electrolysis electrode.

[0047] However, if necessary, the metal layer 10 may be made of titanium mesh or titanium felt, or it may include, without limitation, other configurations that do not include titanium mesh or titanium felt.

[0048] In one embodiment, the catalyst layer 20 can be formed on the metal layer 10.

[0049] In one embodiment, the catalyst layer 20 can be formed by depositing it onto at least a portion of the metal layer 10.

[0050] In one embodiment, if the metal layer 10 is a substrate having multiple surfaces, the catalyst layer 20 can be formed on at least a portion of at least one of the multiple surfaces of the metal layer 10.

[0051] In one embodiment, the catalyst layer 20 may contain silver, iridium, and ruthenium.

[0052] In one embodiment, silver can have excellent conductivity. In the embodiment, as will be described later, silver can function as a carrier or support for iridium and ruthenium.

[0053] In one embodiment, iridium and ruthenium can provide active sites for a water electrolysis reaction (specifically, an oxygen evolution reaction in this disclosure). Exemplarily, iridium and ruthenium can function as catalysts for the oxygen evolution reaction and reduce the reaction overpotential of the oxygen evolution reaction.

[0054] As mentioned above, the silver has excellent electrical conductivity and can function as a catalyst for oxygen evolution reactions. However, its oxygen evolution reaction activity is weak, and when used alone, the excellent oxygen evolution performance of the water electrolysis electrode may not be expected.

[0055] When iridium is applied to a catalyst for water electrolysis electrodes, it can exhibit excellent oxygen evolution reaction activity. On the other hand, when iridium is applied together with silver to a catalyst for water electrolysis electrodes, the electronic structure of the iridium is controlled by the interaction between them, providing reaction active sites and allowing for excellent oxygen evolution performance. However, due to its scarcity, using large quantities of iridium may reduce the economic viability of the water electrolysis electrode.

[0056] When applied as a catalyst for water electrolysis electrodes, ruthenium exhibits excellent oxygen evolution reaction activity and is less rare than iridium, making it economically advantageous. However, ruthenium has poor durability under polymer electrolyte membrane (PEM) water electrolysis conditions, and when used alone, it may reduce the durability of the water electrolysis apparatus.

[0057] In the case of the water electrolysis electrode according to this disclosure, by including silver, iridium, and ruthenium as catalysts for the water electrolysis electrode, a portion of the iridium can be replaced with ruthenium, thereby further reducing the amount of iridium loaded while exhibiting excellent oxygen evolution reaction activity. Furthermore, the introduction of ruthenium induces an additional electronic structure change in iridium, providing an Ir-Ru reaction active site with even better oxygen evolution reaction activity, thereby ensuring remarkably superior oxygen evolution performance.

[0058] In one embodiment, in the water electrolysis electrode according to this disclosure, at least a portion of iridium and ruthenium can be supported on silver. In one embodiment, 0.1 to 15% of Ir and Ru can be supported based on the Ag content. Within this range, the individual amounts of Ir and Ru are not necessarily limited. In one embodiment, the above-mentioned amounts can be measured by ICP analysis, but are not limited thereto.

[0059] In one embodiment, silver, iridium, and ruthenium can be uniformly distributed in the catalyst layer 20. In such embodiments, the silver, iridium, and ruthenium may not be locally distributed in any particular region of the catalyst layer 20.

[0060] In one embodiment, at least some of the silver, iridium, and ruthenium contained in the catalyst layer 20 can interact with each other electrically.

[0061] In the embodiment, at least some of the silver, iridium, and ruthenium in the catalyst layer 20 interact electrically with each other, causing changes in the electronic structure of at least some of the silver, iridium, and ruthenium. In a specific embodiment, such interaction may alter the electronic structure of at least some of the iridium. Such alteration of the electronic structure can further improve the oxygen evolution reaction activity in the catalyst layer 20, and as a result, further improve the oxygen evolution performance of the water electrolysis electrode 100.

[0062] Figure 2 is a drawing showing another example of a cross-section of a water electrolysis electrode according to one embodiment of the present disclosure.

[0063] Referring to Figure 2, in one embodiment, the catalyst layer 20 may include a first layer 21 containing silver and in contact with the metal layer, and a second layer 22 containing iridium and ruthenium and formed on the first layer 21.

[0064] In one embodiment, the silver, iridium, and ruthenium contained in the catalyst layer 20 can form a layered structure. In the embodiment, as described above, the catalyst layer 20 can form a layered structure of a first layer 21 containing silver and a second layer 22 containing iridium and ruthenium.

[0065] In the case of silver, its surface energy is high, making it difficult to produce trimetallic nanoparticles (ternary alloy nanoparticles) in which iridium and ruthenium are uniformly mixed. By forming the layered structure described above, a catalyst layer 20 in which iridium and ruthenium are uniformly supported can be easily produced.

[0066] In one embodiment, at least a portion of the silver contained in the first layer 21 can be chemically bonded with the metal elements of the metal layer 10. Alternatively, in such an embodiment, the water electrolysis electrode 100 can form a layered structure in which the first layer 21 and the second layer 22 are sequentially formed on the metal layer 10. In one embodiment, the chemical bond may include, for example, a metallic bond.

[0067] In one embodiment, at least a portion of the silver contained in the first layer 21 can interact electrically and chemically by chemically bonding with the metal elements of the metal layer 10, and can also bond strongly with the metal layer 10. This can improve the electron transfer performance and durability of the water electrolysis electrode 100.

[0068] In one embodiment, the first layer 21 can be deposited on the metal layer 10 with a uniform thickness. In one embodiment, the second layer 22 can be formed on the first layer 21 with a uniform thickness.

[0069] In one embodiment, the water electrolysis electrode 100 may not contain a binder. In exemplary embodiments, the binder may refer to a common binder used in the industry for binding, and examples include polymer binders such as Nafion, polyvinylidene fluoride (PVDF), polyacrylonitrile, carboxymethylcellulose (CMC), or rubber binders.

[0070] When the aforementioned binder is used, there is a problem that the binder may decompose or undergo side reactions during the water electrolysis process (specifically, the oxygen evolution reaction), which reduces the activity or durability of the water electrolysis electrode (100). On the other hand, the presence of the binder may be a factor that reduces the electrical conductivity performance.

[0071] Furthermore, among the binders exemplified above, Nafion is one of the binders commonly used in this industry, but Nafion is a typical PFAS (per- and polyfluoroalkyl substances), and its use presents the problem of potentially causing environmental issues.

[0072] The water electrolysis electrode 100 according to one embodiment of the present disclosure overcomes the above-mentioned problems by not containing a binder. Furthermore, by directly depositing the catalyst layer 20 onto the metal layer 10 without using a binder, the electrical conductivity and durability are greatly improved by the chemical bond formed between the metal layer 10 and the catalyst layer 20.

[0073] In one embodiment, the water electrolysis electrode 100 may contain iridium and ruthenium in a weight ratio of 9:1 to 5:5. In a specific embodiment, the water electrolysis electrode 100 may contain iridium and ruthenium in a weight ratio of 8:2 to 5:5. In a more specific embodiment, the water electrolysis electrode 100 may contain iridium and ruthenium in a ratio of 7:3 to 5:5. In an exemplary embodiment, the weight ratio may be 7:3, 6.5:3.5, 6:4, 5.5:4.5, or 5:5.

[0074] If the iridium is included in the water electrolysis electrode 100 in excess of the weight ratio range, the effect of improving the oxygen evolution reaction activity due to the interaction of iridium and ruthenium may be difficult to expect. If the iridium is included in the water electrolysis electrode 100 in less than the weight ratio range, in particular, if ruthenium is included in excess of iridium, the durability of the water electrolysis electrode 100 may decrease due to the relatively weak durability of ruthenium catalyst properties, for example, the catalyst layer 20 may dissolve excessively during long-term reactions.

[0075] In one embodiment, the iridium may be present in an amount of 0.3% to 0.5% by weight based on the total weight of the water electrolysis electrode 100. Alternatively, in a particular embodiment, the iridium content may be 0.31% or more by weight, 0.33% or more by weight, 0.35% or more by weight, 0.37% or more by weight, 0.38% or more by weight, 0.4% or more by weight, or 0.41% or more by weight, or 0.49% or less by weight, 0.48% or less by weight, 0.47% or less by weight, or 0.46% or less by weight. In other words, in the water electrolysis electrode 100, the iridium may be present in an amount of 0.3% to 0.5% by weight based on the total weight of the water electrolysis electrode 100. In specific embodiments, it may be present in an amount of 0.31% or more by weight, 0.33% or more by weight, 0.35% or more by weight, 0.37% or more by weight, 0.38% or more by weight, 0.4% or more by weight, or 0.41% or more by weight, and may be present in an amount of 0.49% or less by weight, 0.48% or less by weight, 0.47% or less by weight, or 0.46% or less by weight.

[0076] In one embodiment, the ruthenium may be present in an amount of 0.05% to 0.5% by weight based on the total weight of the water electrolysis electrode 100. Alternatively, in a specific embodiment, the ruthenium content may be 0.06% or more by weight, 0.07% or more by weight, 0.08% or more by weight, or 0.09% or more by weight, or 0.49% or less by weight, 0.45% or less by weight, 0.43% or less by weight, 0.4% or less by weight, 0.38% or less by weight, 0.35% or less by weight, 0.3% or less by weight, 0.28% or less by weight, 0.25% or less by weight, 0.24% or less by weight, 0.23% or less by weight, 0.22% or less by weight, 0.21% or less by weight, 0.2% or less by weight, 0.19% or less by weight, 0.18% or less by weight, 0.16% or less by weight, 0.15% or less by weight, 0.14% or less by weight, or 0.13% or less by weight. In other words, in the water electrolysis electrode 100, the ruthenium may be included in an amount of 0.05% to 0.5% by weight based on the total weight of the water electrolysis electrode 100. In specific embodiments, it may be included in an amount of 0.06% or more by weight, 0.07% or more by weight, 0.08% or more by weight, or 0.09% or more by weight, and may be included in an amount of 0.49% or less by weight, 0.45% or less by weight, 0.43% or less by weight, 0.4% or less by weight, 0.38% or less by weight, 0.35% or less by weight, 0.3% or less by weight, 0.28% or less by weight, 0.25% or less by weight, 0.24% or less by weight, 0.23% or less by weight, 0.22% or less by weight, 0.21% or less by weight, 0.2% or less by weight, 0.19% or less by weight, 0.18% or less by weight, 0.16% or less by weight, 0.15% or less by weight, 0.14% or less by weight, or 0.13% or less by weight.

[0077] The water electrolysis electrode 100 according to one embodiment of the present disclosure can exhibit oxygen generation 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.

[0078] Method for manufacturing water electrolysis electrodes Figure 3 is a step-by-step diagram showing an example of a method for manufacturing a water electrolytic electrode according to one embodiment of the present disclosure.

[0079] Referring to Figure 3, a method for manufacturing a water electrolytic electrode according to one embodiment of the present disclosure includes the step of forming a catalyst layer on a metal substrate, wherein the catalyst layer may contain silver, iridium, and ruthenium.

[0080] In one embodiment, the metal substrate and catalyst layer may have the same configuration as the metal layer 10 and catalyst layer 20 described with reference to Figures 1 and 2.

[0081] In one embodiment, the metal substrate may include at least one selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fiber.

[0082] In one embodiment, the metal substrate may include at least one selected from the group consisting of titanium, nickel, and stainless steel, or an alloy thereof.

[0083] In one embodiment, the metal substrate may include titanium mesh or titanium felt. In a specific embodiment, the metal substrate may include titanium felt. However, the metal substrate may be composed of titanium mesh or titanium felt as needed, or it may include other configurations that do not include titanium mesh or titanium felt, without limitation.

[0084] Referring to Figure 3, in one embodiment, the step of forming a catalyst layer on the metal substrate may include a step S110 in which the metal substrate is brought into contact with a first precursor solution containing silver ions to obtain a metal substrate on which a first layer containing silver is formed, and a step S120 in which the metal substrate on which the first layer is formed is brought into contact with a second precursor solution containing iridium ions and ruthenium ions to form a second layer on the first layer on which iridium and ruthenium are formed.

[0085] In one embodiment, in step S110, the metal substrate 10 is brought into contact with a first precursor solution containing silver ions to obtain a metal substrate on which a first layer containing silver is formed.

[0086] In one embodiment, the first precursor solution containing silver ions may include a silver precursor. In a specific embodiment, the silver precursor may include a silver salt.

[0087] In one embodiment, the first precursor solution may contain at least one selected from the group consisting of silver nitrate, silver acetate, silver sulfate, silver perchlorate, silver acetylacetonate, and silver methanesulfonate, or a mixture thereof. However, the first precursor solution may also be silver nitrate.

[0088] In exemplary embodiments, the first precursor solution may be water, a C1-C6 aliphatic alcohol, or a mixture thereof as the solvent. In specific embodiments, the solvent may be a mixture of water and a C1-C6 aliphatic alcohol. In more specific embodiments, the solvent may be a mixture of water and ethanol. In such embodiments, the mixing ratio of the water-alliphatic alcohol mixture may be 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, or 8:2 by volume, but is not limited thereto, and in one embodiment, the mixing ratio may be 5:5.

[0089] In exemplary examples, the concentration of the silver precursor in the first precursor solution can be 1 mM to 1 M, and in specific examples, the concentration may be 10 mM or more, 30 mM or more, 50 mM or more, 60 mM or more, 70 mM or more, 80 mM or more, or 90 mM or more, or 900 mM or less, 800 mM or less, 700 mM or less, 600 mM or less, 500 mM or less, 450 mM or less, 400 mM or less, 350 mM or less, 300 mM or less, 250 mM or less, 200 mM or less, 150 mM or less, or 120 mM or less.

[0090] In one embodiment, the first precursor solution and the metal substrate 10 can be brought into contact in step S110. In a specific embodiment, step S110 can be performed by drop casting.

[0091] According to the embodiments described above, silver with a high ionization energy can be uniformly coated onto a metal substrate.

[0092] In one embodiment, a metal substrate with the first layer formed thereon can be obtained by step S110. Here, the first layer can be the same as the first layer 21 described with reference to Figures 1 and 2.

[0093] Therefore, according to the above-described embodiment, as mentioned above, the first layer containing silver can be formed on the metal layer with a uniform thickness.

[0094] In one embodiment, step S110, which is the step of obtaining the metal substrate on which the first layer is formed, may further include the step of contacting the metal substrate with the first precursor solution and then drying it. In a specific embodiment, the step of contacting the metal substrate with the first precursor solution and then removing the metal substrate and drying it may further include the step of removing the metal substrate and then drying it.

[0095] In one embodiment, the drying can be carried out at a temperature of 60°C to 100°C, and in a specific embodiment, the drying can be carried out at a temperature of 65°C or higher, 70°C or higher, or 75°C or higher, or at a temperature of 95°C or lower, 90°C or lower, or 80°C or lower.

[0096] In one embodiment, after drying as described above, the metal substrate can be brought into contact with the first precursor solution again. In an exemplary embodiment, the process can be repeated two to five times.

[0097] Therefore, according to the above-described embodiment, as mentioned above, the first layer containing silver can be formed on the metal layer with a more uniform thickness.

[0098] In one embodiment, step S110, which involves obtaining a metal substrate on which the first layer is formed, may further include a step of heat-treating the metal substrate on which the first layer is formed.

[0099] In one embodiment, the heat treatment step can be carried out in a hydrogen atmosphere.

[0100] On the other hand, in one embodiment, the heat treatment step can be carried out at a temperature of 100°C to 900°C for 10 to 600 minutes. In an exemplary embodiment, the temperature may be 150°C or higher, 200°C or higher, 250°C or higher, 300°C or higher, 350°C or higher, or 380°C or higher, or 850°C or lower, 800°C or lower, 750°C or lower, 750°C or lower, 700°C or lower, 650°C or lower, 600°C or lower, 550°C or lower, 500°C or lower, 500°C or lower, 450°C or lower, or 420°C or lower. In exemplary embodiments, the time (required time) may be 30 minutes or more, 40 minutes or more, 50 minutes or more, or 550 minutes or less, 500 minutes or less, 450 minutes or less, 400 minutes or less, 350 minutes or less, 300 minutes or less, 250 minutes or less, 200 minutes or less, 150 minutes or less, 100 minutes or less, or 80 minutes or less.

[0101] Therefore, according to the above-described embodiment, the silver contained in the first layer formed on the metal substrate can have a stable metallic phase, and impurities on the metal substrate can be removed.

[0102] In one embodiment, in step S120, the metal substrate 10 on which the first layer 21 is formed can be brought into contact with a second precursor solution containing iridium ions and ruthenium ions to form a second layer containing iridium and ruthenium on the first layer 21.

[0103] In one embodiment, the second precursor solution containing iridium ions and ruthenium ions may contain iridium precursors and ruthenium precursors. In a specific embodiment, the iridium precursor may contain an iridium salt, and the ruthenium precursor may contain a ruthenium salt.

[0104] In one embodiment, the iridium precursor may include at least one selected from the group consisting of iridium chloride, iridium chloride hydrate, iridium bromide, iridium acetylacetonate, hexachloroiridic acid, sodium hexachloroiridate, and potassium hexachloroiridate, or a mixture thereof. However, the iridium precursor may also be iridium chloride.

[0105] In one embodiment, the ruthenium precursor may include at least one selected from the group consisting of ruthenium chloride, ruthenium chloride hydrate, ruthenium bromide, ruthenium acetylacetonate, and hexachlororuthenate, or a mixture thereof. However, the ruthenium precursor may also be ruthenium chloride.

[0106] In exemplary embodiments, the second precursor solution may be water, a C1-C6 aliphatic alcohol, or a mixture thereof as the solvent. In specific embodiments, the solvent may be a mixture of water and a C1-C6 aliphatic alcohol. In more specific embodiments, the solvent may be a mixture of water and ethanol. In such embodiments, the mixing ratio of the water-alliphatic alcohol mixture may be 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, or 8:2 by volume, but is not limited thereto, and in one embodiment, the mixing ratio may be 5:5.

[0107] In exemplary embodiments, the concentration of the iridium precursor in the second precursor solution may be 1 mM to 10 mM, and in specific embodiments, the concentration may be 2 mM or more, 3 mM or more, 4 mM or more, 4.3 mM or more, or 4.7 mM or more, or 9 mM or less, 8 mM or less, 7 mM or less, 6.5 mM or less, 6 mM or less, 5.7 mM or less, 5.5 mM or less, or 5.2 mM or less.

[0108] In exemplary embodiments, the concentration of the ruthenium precursor in the second precursor solution can be 1 mM to 10 mM, and in specific embodiments, the concentration may be 1.1 mM or more, 1.3 mM or more, 1.5 mM or more, 1.7 mM or more, 1.8 mM or more, 1.9 mM or more, or 2 mM or more, or 9 mM or less, 8 mM or less, 7 mM or less, 6 mM or less, 5 mM or less, 4 mM or less, 3.5 mM or less, 3 mM or less, 2.7 mM or less, or 2.6 mM or less.

[0109] In one embodiment, the second precursor solution may contain iridium ions and ruthenium ions in a molar concentration ratio of 9:1 to 5:5. In a specific embodiment, the second precursor solution may contain iridium ions and ruthenium ions in a molar concentration ratio of 8:2 to 5:5, and more specifically, in a molar concentration ratio of 7:3 to 5:5.

[0110] In the embodiments described above, as previously stated, the iridium precursor and the ruthenium precursor may each include an iridium salt and a ruthenium salt. Therefore, the iridium ions and ruthenium ions contained in the second precursor solution can be configured to be present in the aforementioned molar concentration ratio.

[0111] In exemplary embodiments, the molar concentration ratio may be 7:3, 6.5:3.5, 6:4, 5.5:4.5, or 5:5.

[0112] In the embodiments described above, as shown in Figures 1 and 2, a water electrolytic electrode 100 that satisfies the loading ratio of iridium and ruthenium contained in the second layer 22 can be manufactured.

[0113] In one embodiment, in step S120, the metal substrate 10 on which the first layer 21 containing silver, obtained in step S110, is formed, can be brought into contact with the second precursor solution. In a specific embodiment, step S120 can be performed by drop casting.

[0114] According to the embodiments described above, iridium and ruthenium can be uniformly coated onto the first layer.

[0115] In one embodiment, a metal substrate in which the first and second layers are formed in sequence can be obtained by step S120. Here, the first and second layers can be the same as the first layer 21 and second layer 22 described with reference to Figures 1 and 2.

[0116] Therefore, according to the above-described embodiment, as mentioned above, a second layer containing iridium and ruthenium can be formed on the metal layer with a uniform thickness.

[0117] In one embodiment, step S120 for forming the second layer may further include a step of contacting the metal substrate with the second precursor solution and then drying it. In a specific embodiment, the step of contacting the metal substrate with the second precursor solution and then removing it and drying it may further include a step of removing it and drying it.

[0118] In one embodiment, the drying can be carried out at a temperature of 60°C to 100°C, and in a specific embodiment, the drying can be carried out at a temperature of 65°C or higher, 70°C or higher, or 75°C or higher, or at a temperature of 95°C or lower, 90°C or lower, or 80°C or lower.

[0119] In one embodiment, after drying as described above, the metal substrate can be brought into contact with the second precursor solution again. In an exemplary embodiment, the above process can be repeated two to five times.

[0120] Therefore, according to the above-described embodiment, as mentioned above, the second layer containing iridium and ruthenium can be formed on the first layer with a more uniform thickness.

[0121] In one embodiment, step S120 of forming the second layer may further include a step of heat-treating the metal substrate on which the second layer is formed.

[0122] In one embodiment, the heat treatment step can be carried out in a hydrogen atmosphere.

[0123] On the other hand, in one embodiment, the heat treatment step can be carried out at a temperature of 100°C to 900°C for 10 to 600 minutes. In an exemplary embodiment, the temperature may be 150°C or higher, 200°C or higher, 250°C or higher, 300°C or higher, 350°C or higher, or 380°C or higher, or 850°C or lower, 800°C or lower, 750°C or lower, 750°C or lower, 700°C or lower, 650°C or lower, 600°C or lower, 550°C or lower, 500°C or lower, 500°C or lower, 450°C or lower, or 420°C or lower. In an exemplary embodiment, the time (required time) is 30 minutes or more, 40 minutes or more, or 50 minutes or more, or 550 minutes or less, 500 minutes or less, 450 minutes or less, 400 minutes or less, 350 minutes or less, 300 minutes or less, 250 minutes or less, 200 minutes or less, 150 minutes or less, 100 minutes or less, or 80 minutes or less.

[0124] Therefore, according to the above-described embodiment, the iridium and ruthenium contained in the second layer formed on the first layer can have a stable metallic phase, and foreign matter on the first layer can be removed.

[0125] In one embodiment, the step of acid-treating the metal substrate may be further included before the step of forming a catalyst layer on the metal substrate.

[0126] Referring to Figure 3, the acid treatment step can be performed before step S110. In an exemplary embodiment, the acid treatment step can be prepared by contacting the metal substrate with an acidic solution and then drying it.

[0127] In one embodiment, the acidic solution can be nitric acid, sulfuric acid, hydrochloric acid, acetic acid, citric acid, oxalic acid, or a mixture thereof. On the other hand, the metal substrate can be exposed to such an acidic solution for 12 to 36 hours. Specifically, the metal substrate can be exposed to such an acidic solution by immersing it in the solution or by spraying the solution onto the metal substrate.

[0128] In the embodiment described above, as shown in Figure 2 above, a water electrolysis electrode 100 can be manufactured in which a first layer 21 and a second layer 22 are formed sequentially on the metal layer 10. By employing a two-step process in which the first layer 21 is formed first on the metal layer 10, and then the second layer 22 is formed, the oxidation of the metal elements of the metal substrate during the water electrolysis reaction can be minimized.

[0129] water electrolysis equipment

[0130] A water electrolysis apparatus according to one embodiment of the present disclosure includes an anode, a cathode, and a membrane located between the anode and the cathode, wherein the anode includes a metal layer and a catalyst layer formed on the metal layer, and the catalyst layer may include silver, iridium, and ruthenium.

[0131] In one embodiment, the water electrolysis electrode described above with reference to Figures 1 to 3 can be used as an anode in a water electrolysis apparatus according to one embodiment of the present disclosure.

[0132] In one embodiment, the water electrolysis apparatus may include an electrolyte that is an aqueous or non-aqueous medium in which the anode and cathode are immersed or at least in contact with the anode and cathode, and which allows ions to move.

[0133] In one embodiment, the membrane can function as a separator. That is, the membrane is located between the anode and the cathode and can separate the anode and the cathode.

[0134] In an exemplary embodiment, the membrane can function as an ion exchange membrane (cation exchange membrane or anion exchange membrane). In an exemplary embodiment, the membrane may be a porous polymer membrane, a porous ceramic membrane, or the like.

[0135] In one embodiment, the cathode may be a conductive metal substrate, similar to the anode (or water electrolysis electrode according to one embodiment of the present disclosure). Alternatively, a cathode catalyst may be supported on the conductive substrate of the cathode. In exemplary embodiments, the cathode catalyst may be platinum, ruthenium, iridium, osmium, palladium, platinum-ruthenium alloys, platinum-osmium alloys, platinum-palladium alloys and oxides thereof, or other carbon material catalysts, without limitation, such as having no side reactions with the electrolyte, being conductive, and simultaneously exhibiting low overpotential in the hydrogen evolution reaction.

[0136] In exemplary embodiments, the electrolyte may be an acidic electrolyte. Examples of such electrolytes include sulfuric acid, hydrochloric acid, and nitric acid. The pH of the electrolyte may be 6 or less, 5 or less, 4 or less, or 3.5 or less.

[0137] The water electrolysis apparatus according to one embodiment can be preferably used in, for example, redox flow batteries and other fuel cells, but is not necessarily limited to these.

[0138] The embodiments of this disclosure will be further described below with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are illustrative of this disclosure and do not limit the scope of the attached claims. It will be obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope of the categories and technical ideas of this disclosure, and that these variations and modifications will naturally fall within the scope of the attached claims.

[0139] Manufacturing example Example 1 - Fabrication of IrRu-Ag / Ti electrodes

[0140] A 100 mM first 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 the silver precursor was completely dissolved.

[0141] The first precursor solution produced in this manner was drop-cast onto titanium felt acid-treated with oxalic acid (10 wt.%), and then dried on an 80°C hot plate. This process was repeated three times. Subsequently, a silver-coated Ag / Ti electrode was produced through a heat treatment process at 400°C for 1 hour under H2 conditions.

[0142] Furthermore, iridium chloride hydrate (Sigma) and ruthenium chloride hydrate (Sigma) were added to a mixed solution of distilled water / ethanol (volume ratio 1:1). The mixture was then sonicated and stirred until the iridium and ruthenium precursors were completely dissolved to prepare a second precursor solution with concentrations of 5 mM iridium precursor and 2.2 mM ruthenium precursor.

[0143] The second precursor solution thus produced was drop-cast onto the Ag / Ti electrode, and the drying process on an 80°C hot plate was repeated four times. Subsequently, the electrode was heat-treated at 400°C for 1 hour under H2 conditions to produce an IrRu-Ag / Ti electrode coated with silver, iridium, and ruthenium.

[0144] Example 2 - Fabrication of IrRu-Ag / Ti electrode

[0145] An IrRu-Ag / Ti electrode was manufactured in the same manner as in Example 1, except that a second precursor solution was prepared and used with an iridium precursor concentration of 5 mM and a ruthenium precursor concentration of 5 mM.

[0146] Comparative Example 1 - Manufacturing of Ir-Ag / Ti electrodes

[0147] An Ir-Ag / Ti electrode was prepared in the same manner as in Example 1, except that a second precursor solution with an iridium precursor concentration of 6.7 mM was used, which was prepared by adding only iridium chloride hydrate to a mixed solution of distilled water / ethanol (volume ratio 1:1), and then sonicating and stirring until the iridium precursor was completely dissolved.

[0148] Comparative Example 2 - Manufacturing of Ir / Ti electrodes

[0149] An Ir / Ti electrode was manufactured in the same manner as in Comparative Example 1, except that the step of contacting the titanium felt with the first precursor solution was omitted.

[0150] Comparative Example 3 - Manufacturing of Ag / Ti electrodes

[0151] An Ag / Ti electrode was manufactured in the same manner as in Example 1, except that the step of contacting the titanium felt with the second precursor solution was omitted.

[0152] Comparative Example 4 - Preparation of IrO2 Electrode

[0153] We prepared a commercially available oxidation electrode catalyst, IrO2black (100% by weight, Alfa Aesar).

[0154] Evaluation example

[0155] Evaluation Example 1 - Evaluation of Electrode Physical Properties

[0156] (1) SEM (Scanning Electron Microscope) / EDS (Energy Dispersive Spectrometer) mapping analysis

[0157] Figure 4 shows the SEM / EDS mapping image of the electrode in Example 1.

[0158] An EDS mapping image of the example electrode was acquired using a scanning electron microscope (Apreo) equipped with an EDS detector, and this is shown in Figure 4. The measurement conditions were an acceleration voltage of 15 kV and a magnification of 500x.

[0159] The analysis results, as shown in Figure 4, confirm that silver, iridium, and ruthenium are simultaneously present in the electrode of Example 1, and that silver, iridium, and ruthenium are uniformly deposited across the entire titanium felt.

[0160] (2) XRD (X-ray diffraction) analysis

[0161] Figure 5 is a graph showing the XRD patterns of the electrodes for Example 1, Comparative Example 2, and Comparative Example 3.

[0162] The metal crystal planes of the electrodes in Example 1, Comparative Example 2, and Comparative Example 3 were confirmed using an X-ray diffraction analyzer (PANalytical). Measurements were taken using Cu Kα radiation at 40 kV and 100 mA, with a scan speed of 6° per minute at 0.01° intervals, covering a range of 10 to 80°. The measured patterns are shown in Figure 5. For further comparison, in addition to the electrodes in Example 1, Comparative Example 2, and Comparative Example 3, a general titanium electrode was also measured.

[0163] As shown in Figure 5, the analysis results revealed that an iridium peak was observed in the pattern of Comparative Example 2 electrode, and a silver peak was observed in the pattern of Comparative Example 3 electrode. On the other hand, in Example 1 electrode, only a peak for silver was observed, and no peaks for iridium or ruthenium were observed. When considered together with the analysis results of Evaluation Example 1 (1) above, it was confirmed that iridium and ruthenium are very uniformly distributed below 10 nm, making it difficult to confirm the peaks for iridium and ruthenium.

[0164] (3)XPS (X-ray photoelectron spectroscopy) analysis

[0165] Figure 6 is a graph showing the XPS analysis results for the electrodes of Example 1 and Comparative Example 1. Figure 7 is a graph showing the XPS analysis results for the electrodes of Example 1 and Comparative Example 1.

[0166] 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, Escalab 250Xi, Thermo Fisher Scientific), and the results are shown in Figures 6 and 7.

[0167] The analysis results, as shown in Figures 6 and 7, confirm that iridium is supported on the electrode of Example 1. In particular, in the case of the electrode of Example 1, a shift in the main peaks of iridium and silver can be observed compared to the electrode of Comparative Example 1. This confirms the additional presence of ruthenium in the catalyst layer in addition to silver and iridium, and further confirms that the electronic structure of iridium and silver has been altered by interaction with ruthenium.

[0168] (4) Element content analysis

[0169] Figure 8 is a graph comparing the amounts of iridium and ruthenium metal supported in the catalyst layers of the electrodes in Example 1 and Comparative Example 4, as determined by ICP mass spectrometry.

[0170] By inductively coupled plasma mass spectrometry (ICP-MS), the metal element contents present in the catalyst layers of the water electrolysis electrodes produced in Example 1 and Comparative Example 4 were analyzed. For the electrodes of Example 1 and Comparative Example 4, an inductively coupled plasma atomic emission spectrometer (ICP-AES, PerkinElmer 350S) was used to analyze the contents of the metal elements present in the catalyst layers of each electrode, and this is shown in FIG. 8.

[0171] As a result of the analysis, referring to FIG. 8, the total content of iridium and ruthenium present in the catalyst layer of the Example 1 electrode is 0.055 mg / cm 2 level, and it was confirmed that the noble metal loading amount is significantly lower than that of the electrode of Comparative Example 4 having an iridium content of 1.7 mg / cm 2 level. It can be confirmed that the electrode of Example 1 has rather excellent oxygen generation reaction activity compared to the electrode of Comparative Example 4, as will be described later, despite the significantly low noble metal loading amount.

[0172] Evaluation Example 2 - Evaluation of Electrochemical Characteristics of Electrodes

[0173] FIG. 9 is a diagram showing an example of a three-electrode system configured for the evaluation of electrochemical characteristics. FIG. 10 is a graph showing the oxygen generation performance of each of the electrodes of Example 1, 2 and Comparative Examples 1 to 4, represented by a current density vs voltage curve. FIG. 11 is a graph showing the oxygen generation performance of the Example 1 electrode evaluated by cycle, represented by a current density vs voltage curve.

[0174] A three-electrode system, as shown in Figure 9, was constructed using the electrodes manufactured in the examples and comparative examples as working electrodes 100, Ag / AgCl (sat. 3M KCl) as a reference electrode 110, and a graphite rod as a counter electrode 120. Each electrode was immersed in a 0.5M H2SO4 acidic solution 150.

[0175] The performance of the oxygen evolution reaction was evaluated using each of the three electrode systems described above, each configured with one of the electrodes manufactured in the examples and comparative examples as the working electrode. The polarization of the oxygen evolution reaction in each three electrode system was measured and evaluated at room temperature with a scan rate of 10 mV / s. At this time, all measured values ​​were expressed as "vs RHE (reversible hydrogen electrode)", and the measurement results are shown in Figure 10 and Table 1 below.

[0176] [Table 1]

[0177] Referring to Figure 10 and Table 1, the current density is 10 mA / cm². 2 When comparing the oxygen evolution reaction performance against the standard, it was confirmed that the activity was superior in the following order: Example 2, Example 1, Comparative Example 1, Comparative Example 4, Comparative Example 2, and Comparative Example 3.

[0178] Specifically, the electrodes in Example 1 and Example 2 have a current of 10 mA / cm². 2 To obtain the corresponding current density values, only overvoltages of 0.237V and 0.228V were applied, respectively. These values ​​are significantly smaller than those of Comparative Examples 4 and 2, and it was confirmed that the overvoltage was significantly reduced, especially compared to Comparative Example 1, which did not have ruthenium loaded.

[0179] As confirmed in Evaluation Example 1 above, the example electrode, despite having a significantly lower amount of catalyst metal supported compared to Comparative Example 4, was found to have superior oxygen generation performance compared to Comparative Example 4.

[0180] This is thought to be because, in an electrode manufactured according to one embodiment of the present disclosure, silver, iridium, and ruthenium are uniformly deposited onto a metal substrate (titanium mesh), and the effective interaction of these elements changes the electronic structure of iridium, which acts as a reaction active site, thereby improving oxygen evolution performance. Furthermore, the high electrical conductivity and acid resistance of silver, along with the increased electrochemical activity due to the introduction of additional ruthenium, also contribute to the improved activity.

[0181] On the other hand, while performing an oxygen evolution reaction for 500 cycles using the three-electrode system described above, the oxygen evolution performance of the electrode in Example 1 was evaluated for each cycle (1 cycle, 100 cycles, and 500 cycles), and this is shown in Figure 11.

[0182] Referring to Figure 11, the stability evaluation results showed that the current remained at 200 mA / cm² even after 500 cycles. 2 It was confirmed that there was no overvoltage change. This confirmed that the long-term reaction stability of the electrode according to one embodiment of the present disclosure is also excellent.

[0183] The above-described examples are merely illustrative of the application of the principles of this disclosure, and other configurations may be further included without departing from the scope of this disclosure. [Explanation of Symbols]

[0184] 10: Metal layer 20: Catalyst layer 21: 1st layer 22: 2nd layer 100: Water electrolysis electrode

Claims

1. Metal layer, The catalyst layer formed on the metal layer comprises, The catalyst layer is a water electrolysis electrode containing silver, iridium, and ruthenium.

2. The aforementioned metal layer is A water electrolytic electrode according to claim 1, comprising at least one selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fibers.

3. The aforementioned metal layer is The water electrolytic electrode according to claim 1, comprising at least one selected from the group consisting of titanium, nickel, and stainless steel, or an alloy thereof.

4. The aforementioned metal layer is A water electrolytic electrode according to claim 1, comprising titanium felt.

5. The water electrolysis electrode according to claim 1, wherein at least a portion of the silver, iridium, and ruthenium contained in the catalyst layer interact electrically with each other.

6. The catalyst layer is A first layer containing the aforementioned silver and in contact with the aforementioned metal layer, The water electrolysis electrode according to claim 1, comprising a second layer formed on the first layer, the iridium and ruthenium mentioned above.

7. The water electrolytic electrode according to claim 6, wherein at least a portion of the silver contained in the first layer is chemically bonded with the metal elements of the metal layer.

8. The water electrolysis electrode is A water electrolytic electrode according to claim 1, which does not contain a binder.

9. The water electrolysis electrode is The water electrolysis electrode according to claim 1, comprising iridium and ruthenium in a weight ratio of 9:1 to 5:

5.

10. The water electrolysis electrode is The water electrolytic electrode according to claim 1, wherein the iridium is contained in an amount of 0.3 to 0.5% by weight based on the total weight of the water electrolytic electrode.

11. The water electrolysis electrode is The water electrolytic electrode according to claim 1, wherein the ruthenium is contained in an amount of 0.05 to 0.5% by weight based on the total weight of the water electrolytic electrode.

12. The step includes forming a catalyst layer on a metal substrate, The catalyst layer comprises silver, iridium, and ruthenium, and is a method for manufacturing a water electrolysis electrode.

13. The aforementioned metal substrate is A method for manufacturing a water electrolytic electrode according to claim 12, comprising at least one selected from the group consisting of metal mesh, metal foam, metal foil, metal felt, and metal fibers.

14. The aforementioned metal substrate is A method for producing a water electrolytic electrode according to claim 12, comprising at least one selected from the group consisting of titanium, nickel, and stainless steel, or an alloy thereof.

15. The step of forming a catalyst layer on the metal substrate is: The steps include: bringing the metal substrate into contact with a first precursor solution containing silver ions to obtain a metal substrate on which a first layer containing silver has been formed; A method for producing a water electrolytic electrode according to claim 12, comprising the steps of: contacting a metal substrate on which the first layer is formed with a second precursor solution containing iridium ions and ruthenium ions to form a second layer containing iridium and ruthenium on the first layer.

16. The step of obtaining the metal substrate on which the first layer is formed is: A method for manufacturing a water electrolytic electrode according to claim 15, comprising the step of heat-treating a metal substrate on which the first layer is formed.

17. The step of forming the aforementioned second layer is: A method for manufacturing a water electrolytic electrode according to claim 15, comprising the step of heat-treating a metal substrate on which the second layer is formed.

18. The method for producing a water electrolytic electrode according to claim 12, further comprising the step of acid-treating the metal substrate before the step of forming a catalyst layer on the metal substrate.

19. The second precursor solution is A method for producing a water electrolysis electrode according to claim 15, comprising iridium ions and ruthenium ions in a molar concentration ratio of 9:1 to 5:

5.

20. A-scatter, Cathode and, The membrane located between the anode and cathode, The anode includes a metal layer and a catalyst layer formed on the metal layer. The catalyst layer comprises silver, iridium, and ruthenium in a water electrolysis apparatus.

Images