JPS6145712B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an anode for water electrolysis, and more particularly to an anode having extremely low deterioration in characteristics even in an oxidizing environment, particularly an anode having low oxygen overvoltage characteristics, and a method for manufacturing the same. Various types of low oxygen overvoltage anodes have been proposed, particularly as anodes for water electrolysis of alkaline aqueous solutions. Oxygen gas is produced from the anode chamber and hydrogen gas is produced from the cathode chamber by electrolysis in a water electrolyzer containing an alkaline aqueous solution, which is already a well-known industrial water electrolysis method for producing oxygen and hydrogen. As the anode of this electrolytic cell, iron, nickel, Raney nickel, or the like is preferably used. However, these oxygen overvoltages are not particularly low, and in the case of nickel, it has been observed that the overvoltage increases over time. As a result of our deep investigation into this phenomenon, the present inventors discovered that the electrode activity decreases (that is, the oxygen overvoltage increases) when the surface of nickel, which is an active component of the electrode, becomes nickel hydroxide or changes in quality. In order to prevent this deterioration, a third noble metal, a component selected from rhenium, is added to known metal particles consisting of a first component such as nickel or cobalt and a second component such as aluminum, zinc, magnesium, or silicon. It was discovered that an alloy containing the same alloy has a remarkable effect, and that an electrode having a surface layer with the same alloy composition instead of particles has the same effect.
The present invention has been completed, and the present invention consists of a component X consisting of nickel and/or cobalt, a component Y selected from aluminum, zinc, magnesium, and silicon, and a component Z selected from noble metals and rhenium.
An anode for water electrolysis consisting of an alloy in which the components X, Y, and Z are in the range surrounded by points A, B, C, and D in FIG. 1, on the electrode core, nickel and/or Component X consisting of cobalt, Component Y selected from aluminum, zinc, magnesium, and silicon, and Component Z selected from noble metals and rhenium.
A low oxygen overvoltage anode comprising a layer of an alloy consisting of nickel and/or nickel, in which the components X, Y, and Z are in the range surrounded by points A, B, C, and D in FIG. Component X consisting of cobalt, component Y selected from aluminum, zinc, magnesium, and silicon, and component Z selected from precious metals and rhenium are in the range surrounded by points A', B', C', and D' in Figure 4. Electrode active metal particles made of a certain alloy are uniformly dispersed in a plating bath and co-electrodeposited onto the electrode core, or coated onto the electrode core by coating, dipping, baking, or electroplating. The gist of the present invention is a method for manufacturing a highly durable low oxygen overvoltage anode characterized by providing a layer of the above-mentioned alloy. As is well known, the term "noble metal" refers to gold, silver, and platinum group metals (ie, platinum, rhodium, ruthenium, palladium, and iridium). Here, FIG. 1 is a three-component diagram of a component X consisting of nickel and/or cobalt, a component Y selected from aluminum, zinc, magnesium, and silicon, and a component Z selected from noble metals and rhenium, which is an anode of the present invention. It is necessary that the alloy composition of each metal is within the range surrounded by points A, B, C, and D in FIG. Preferably, the range is A, B, E, F. Here, the amounts of (X, Y, Z) components at points A, B, C, and D are A(99.6, 0, 0.4) and B, respectively, in weight%.
(79.6, 20, 0.4), C (40, 20, 40), D (40,
0,60), and the amounts of (X, Y, Z) components at points A, B, E, F are respectively A
(99.6, 0, 0.4), B (79.6, 20, 0.4), E (60,
20, 20), F(80, 0, 20). The effects of the present invention are due to the inclusion of a component selected from noble metals and rhenium as one component of the alloy composition, but why does the inclusion of these components prevent the formation of hydroxides of nickel or cobalt? The details have not yet been clarified. However, the present inventors have found that among these components, rhodium and iridium are most suitable for achieving the effects of the present invention. That is, among metals, when rhodium and iridium are used, an especially low oxygen overvoltage can be maintained for a longer period of time even under harsher environmental conditions. The reason why it is preferable for the alloy of the anode of the present invention to have a composition surrounded by ABCD in Fig. 1 is because an alloy with a composition outside the above range may not be able to maintain a low oxygenation voltage over a long period of time, or the oxygen overvoltage itself may be too high. This is because the expected low oxygen overvoltage and durability will hardly change even if the content of the noble metal or rhenium component is increased from the initial level or exceeds this range. When the above-mentioned alloy is in the form of particles, the average particle size is related to the porosity of the electrode surface and the dispersibility of the particles during electrode manufacture, which will be described later, but a range of 0.1 μm to 100 μm is sufficient. In the above range, preferably 0.9μ to 50μ, more preferably 1μ to 30μ from the viewpoint of porosity of the electrode surface, etc.
μ. Furthermore, the layer of the alloy of the invention is preferably superficially porous in order to achieve a lower oxygen overpotential of the electrode. This surface porosity does not only mean that the entire surface of the particle is porous when the alloy is a particle; it also means that only the portion exposed from the metal layer described above becomes porous. In addition, when the alloy is provided in a layered manner on the electrode core, such as a plating layer, it is sufficient that the layer is porous due to unevenness or the like. As for the degree of porosity, it is preferable that the degree is quite large, but if the degree of porosity is excessively large, the mechanical strength of the particles decreases, so it is preferable that the porosity is 20 to 90%. Within the above range, it is more preferably 35 to 85%, particularly preferably 50 to 80%. Note that the above-mentioned porosity is a value measured by a known water displacement method. Various methods can be used to make the alloy porous, but regardless of whether the alloy is in the form of particles or not, for example, component
A preferred method is to remove part or all of the metal component Y from an alloy consisting of Y and Z to make it porous. In such a case, it is particularly preferable to treat an alloy in which components X, Y, and Z are uniformly blended in predetermined proportions with caustic alkali treatment to remove at least a portion of the metal component Y. In the case of the anode of the present invention, it is not necessarily necessary to treat it with caustic alkali before installing it in the electrolytic cell, and since the anolyte used is under caustic alkaline conditions, the metal of component Y is gradually removed during electrolysis. , can serve as the desired anode. Various composition combinations of the above metal particles can be used, and a typical example is Ni.
−Al−Rh, Ni−Al−Ir, Ni−Zn−Rh, Ni−Zn−
Ir, Ni−Si−Rh, Ni−Si−Ir, Co−Al−Rh, Co
−Al−Ir, Co−Zn−Rh, Co−Zn−Ir, Co−Si−
Rh, Co−Si−Ir, Ni−Mg−Rh, Ni−Mg−Ir,
Possible examples include Co-Mg-Rh, Co-Mg-Ir, etc. Among these, a particularly preferable combination is Ni-Al-
Rh, Ni-Al-Ir, Co-Al-Rh, Co-Al-Ir. The conditions for caustic treatment vary depending on the composition of the starting alloy, but in the case of alloys with the compositions described below, the caustic alkali concentration (NaOH equivalent) is 10 to 10.
It is preferable to immerse it in a 35% by weight aqueous solution at 10 to 50°C for 0.5 to 3 hours. The reason for this is that component Y was selected on the condition that it should be removed as easily as possible. Further, component Z is not removed by the alkali treatment, or even if it is removed, it is only a small amount. When the above-mentioned alloy is in the form of particles, the layer for firmly providing the particles on the metal core is preferably made of the same metal as component X constituting the alloy particles. Thus, a large number of the above-mentioned particles are attached to the electrode surface of the anode of the present invention, and when viewed macroscopically,
The anode surface is microporous. The same applies to the case where the surface of the electrode core body is uniformly coated with an alloy layer, but unlike the case where alloy particles are used, there is no metal layer serving as a binder. Thus, in the anode of the present invention, the electrode surface is coated with an alloy containing nickel and/or cobalt, which itself has a low oxygen overvoltage, and as described above, the electrode surface is microporous. The active surface of the electrode becomes larger accordingly, and the synergistic effect of these makes it possible to effectively reduce the oxygen overvoltage. Moreover, in the case of using alloy particles in the present invention,
Since the layer made of the metal is firmly attached to the electrode surface, it is less susceptible to deterioration due to falling off, and the durability of the low oxygen overvoltage is particularly excellent. The electrode core of the present invention may be made of any suitable conductive metal, such as Ti, Zr, Fe, Ni, V,
A metal selected from Mo, Cu, Ag, Mn, platinum group metals, graphite, and Cr, or an alloy selected from these metals can be used. Of these, Fe alloy (Fe-Ni alloy, Fe
-Cr alloy, Fe-Ni-Cr alloy, etc.), Ni, Ni alloy (Ni-Cu alloy, Ni-Cr alloy, etc.), etc. are preferably used. Particularly preferable materials for the electrode core are Ni, Fe-Ni alloy, and Fe-Ni-Cr alloy. The structure of the electrode core can be made into any suitable shape and size depending on the structure of the electrode used. The shape may be, for example, plate-like, porous, net-like (for example, expanded metal), or slat-like, and these may be flat, curved, or cylindrical. The thickness of the layer of the present invention is sufficient if it is 20 to 200μ, more preferably 25 to 150μ, particularly preferably
It is 30-100μ. Cross-sectional views of the electrode surface of the present invention are shown in FIGS. 2 and 3. As shown in FIG. 2, a layer 2 made of metal is provided on the electrode core 1 via an intermediate layer 4, and electrode active metal particles 3 are provided in the layer so as to be exposed from the surface of the layer. include. The proportion of particles in layer 2 is preferably 5 to 80 wt%, more preferably 10 to 50 wt%. By providing an intermediate layer made of a metal selected from Ni and Co between the electrode core and the layer containing alloy particles, the durability of the electrode of the present invention can be further improved. Such an intermediate layer may be of the same type or a different type from the metal of the above-mentioned layer, but from the viewpoint of adhesion between the intermediate layer and the above-mentioned layer, these intermediate layers and the metals of the layer are of the same type. It is preferable. The thickness of the intermediate layer is 5.
~100μ is sufficient, more preferably 20
~80μ, particularly preferably 30-50μ. Of course, it is not always necessary to provide the intermediate layer as described above. FIG. 3 is a cross-sectional view of the anode of the present invention in which the surface of the electrode core is uniformly coated with an alloy layer, in which 1 is the electrode core, 5 is a uniform surface layer of an alloy with electrode activity, 6 is the middle layer. The electrode of the present invention shown in Fig. 2 has a large number of particles exposed on the electrode surface, but the surface layer is porous mainly due to the gaps between the particles, and the alloy component Y The voids left behind after removal also contribute to porosity. As mentioned above, the degree of porosity is also related to the reduction in oxygen overpotential, so that the purpose can be sufficiently achieved if the degree of porosity is 1000 μF/cm ² or more in electric double layer capacity. Within the above range, preferably 2000 μF/cm ² or more,
Particularly preferably, it is 5000 μF/cm ² or more. Electric double layer capacity is the capacitance of an electric double layer formed when positive and negative ions are relatively distributed over a short distance near the electrode surface when the electrode is immersed in an electrolyte solution. indicates the actually measured differential capacity. This capacitance increases as the electrode surface becomes larger. Therefore, when the electrode surface becomes porous and the electrode surface area increases, the electric double layer capacity of the electrode surface also increases. Therefore, due to the electric double layer capacity,
The electrochemically effective electrode surface area, that is, the degree of porosity of the electrode surface can be determined. In addition, since the electric double layer capacity changes depending on the temperature at the time of measurement, the type of electrolyte solution, the concentration, the electrode potential, etc., the electric double layer capacity of the present invention is the value measured by the following method. means. Test piece (electrode) in 40wt% NaOH aqueous solution (25℃)
A platinum plate with black platinum, which has an apparent area approximately 100 times that of the test piece, is inserted as a counter electrode, and the cell impedance in this state is measured using a vector impedance meter to determine the electric double layer capacity of the test piece. Various methods can be used to specifically form the electrode surface layer, such as a dispersion plating method, a melt coating method, a baking method, an alloy plating method, and a molten liquid immersion method. In the case of using alloy particles, the dispersion plating method is particularly preferable because the particles of the present invention can be attached well. In the dispersion plating method, plating is performed using an electrode core as a cathode in an aqueous solution containing the metal forming the metal layer, in which alloy particles mainly composed of nickel, for example, are dispersed. The above metal and alloy particles are co-electrodeposited. In more detail, the particles in the bath become bibolar due to the influence of the electric field, and when they approach the cathode surface, they increase the local current density of the plating, and when they come into contact with the cathode, they undergo the usual reduction of metal ions. It is thought that the metal plating is co-electrodeposited on the core body. For example, when a nickel layer is used as the metal layer, a total nickel chloride bath, a high nickel chloride bath, a nickel chloride-nickel acetate bath, etc. can be used.
When a cobalt layer is used as the metal layer, a total cobalt chloride bath, a high cobalt chloride bath, a cobalt chloride-cobalt acetate bath, etc. can be used. In this case, the pH of the bath is important. That is, the electrode-active metal particles dispersed in the plating bath generally have oxygen attached to their surfaces;
In this state, the bond with the metal layer is not sufficient, and particles may peel off during use as an electrode. To prevent this, it is necessary to reduce the amount of oxygen attached to the surface of the particles. For this purpose, it is preferable that the plating bath has a pH of 1.5 to 3.0. In the case of the present invention, the metal particles include a component X made of nickel and/or cobalt, a component Y selected from aluminum, zinc, magnesium, and silicon, and a component Z selected from noble metals and rhenium at point A in FIG. It is necessary that the alloy be in the range surrounded by ', B', C' and D'. In addition, the alloy components (X, Y, Z) of A', B', C', and D' in Fig. 4 are expressed as A' (59.8, 59.8,
40, 0.2), B' (39.8, 60, 0.2), C' (5, 60,
35), D′(12, 40, 48). More preferable ranges include A′, B′, E′,
F′, A′: (59.8, 40, 0.2), B′:
(39.8, 60, 0.2), E′: (30, 60, 10), F′:
(50, 40, 10). . The reason for this is that if it deviates from this range, it may not be possible to secure a sufficient amount of adhesion during the electrodeposition process, or even if electrodeposition is possible, the adhesion strength may be low. This is because the activity as an electrode catalyst is not sufficient. Alternatively, even if the amount of the noble metal component considerably exceeds this range, the oxygen overvoltage reduction effect and durability will not be significantly improved. As described above, it is preferable from the viewpoint of adhesive strength of the particles that the amount of oxygen attached to the surface portion of the particles that comes into contact with the metal layer is small. It is preferable to form an oxide film partially on the material to stabilize it. The proportion of such particles in the bath is 1 g/~
It is preferable to set the amount to 200 g/, particularly 1 g/ to 50 g/, and more preferably 1 g/ to 10 g/, in order to improve the adhesion of particles to the electrode surface.
In addition, the temperature conditions during dispersion plating work are 20 to 80℃,
Especially at 30 to 60℃, current density is 1A/dm ² to 20A/
^dm2 , especially 1 A/ ^dm2 to 10 A/ ^dm2 . It goes without saying that additives for reducing strain, additives for promoting co-electrodeposition, etc. may be added to the plating bath as appropriate. In addition, as mentioned above, when providing an intermediate layer between the electrode core and the metal layer containing particles, the electrode core is first plated with Ni or Co, and then the above-mentioned dispersion plating method or melt spraying method is used. A metal layer containing particles is formed thereon by means of. As the plating bath in such a case, the various plating baths mentioned above can be employed. In this way, an electrode is obtained in which the particles of the present invention are attached to the electrode core via a metal layer. Next, specific means for providing the alloy layer having uniform electrode activity on the electrode core will be explained. As mentioned above, specific methods for this may include a coating method, a dipping method, a baking method, an electroplating method, and the like. The coating method is preferably a method of melting and spraying a fine rod or powder of the alloy as shown in FIG.
For this melt spray, a plasma spray device, an oxygen-hydrogen flame spray device, an oxygen-acetylene flame spray device, etc., which are commonly used in the melt coating method, can be used. The immersion method is a method in which an electrode core is immersed in a molten liquid of the above-mentioned alloy to form a coating layer of the alloy on the core, and the temperature of the molten alloy is below the melting point of the alloy.
A temperature 50 to 200℃ higher is better. In the case of Ni-Al-Rh, the melting point is about 1500°C, so it is preferable to form an alloy coating layer on the electrode core by dipping and pulling at about 1600°C. In the baking method, pre-prepared fine powder particles with a particle size of 100μ or less are applied to the electrode core using a suitable polymer compound, especially a water-soluble polymer aqueous solution as a binder, and then heated to bake the binder. This method involves volatilizing the particles, sintering the particles, and fixing them to the substrate. Sintering is usually carried out at a temperature 100 to 300°C lower than the melting point, and preferably sintered under pressure. In the electroplating method, a solution (preferably an aqueous solution) of a metal salt having components X, Y, and Z in the range shown in Figure 4 is prepared, and the electrode core is immersed as a cathode in this solution, and electroplating is performed. This is the so-called alloy plating method. However, this method cannot be adopted when Y is Al or Mg, but is possible when Y is Zn.
For plating conditions, usual conditions may be used; for example, NiSO ₄ 7H ₂ O, ZnSO ₄ , KReO ₄ ,
A Ni-Zn-Re alloy layer can be formed by plating a mixed solution of (NH ₄ ) ₂ SO ₄ at a current density of about 1 A/dm ² and a temperature of about 60° C. with pH set to 4.0. It is also effective to attach a non-electronically conductive substance to the surface of the thus obtained low oxygen overvoltage anode. When the anode of the present invention is used as an anode for water electrolysis of an alkaline aqueous solution, silicate ions may be present in the anolyte, and these may discharge on the anode and silica may be deposited on the anode. In this case, the active surface of the anode will be lost and the oxygen overpotential will increase. In order to prevent such discharge precipitation, a non-electronically conductive substance such as a fluorine-containing resin (such as PTFE) is attached on the anode of the present invention and furthermore on the metal particles protruding from the anode surface. It is effective to keep it. As a specific means for this purpose, a method as disclosed in Japanese Patent Application No. 126921/1988 can be preferably adopted. The anode thus obtained is then treated with caustic alkali (e.g., immersed in an aqueous caustic solution) as necessary to elute and remove at least a portion of the metal of component Y in the alloy particles, and remove the particles or the electrode surface layer. to make it porous. The conditions in such a case are as described above. In addition, when an alloy of the above-mentioned components X, Y, and Z is adopted, it is preferable to perform the caustic alkali treatment as described above. Alternatively, alkaline treatment may be performed while actually performing electrolysis. In such a case, the metal of component Y is eluted during the electrolysis process, and the overvoltage of the anode is reduced. However, although the aqueous caustic alkaline solution produced is slightly contaminated by the eluted metal ions of component Y, this generally does not pose a problem. The electrode of the present invention can of course be used as an anode for electrolysis of aqueous alkaline solutions using a solid electrolyte method or an ion removal method, but can also be used as an anode for water electrolysis of aqueous alkaline solutions using a porous diaphragm (for example, Aspest diaphragm). can also be adopted. Next, examples of the present invention will be described. Examples 1-12 An alloy powder (200 mesh bath) having the composition shown in Table 1 was prepared and used in Examples 1-10, 14-16.
For details, see Example 12 of Japanese Patent Application Laid-open No. 112785/1985.
In addition, for Examples 11 to 13, NiCl ₂ 6H ₂ O in Example 12 of the same publication was replaced with CoCl ₂ 6H ₂ O (concentration
A low oxygen overvoltage electrode was manufactured using a dispersion plating method based on a plating method in which the Ni plate anode was replaced with a Co plate anode (however, the development temperature after plating was 50° C.). A part of the metal particles on the obtained electrode was peeled off and its composition was investigated. The results are also listed in Table 1. Next, these electrodes were constructed using a fluorine-containing cation exchange membrane (manufactured by Asahi Glass Co., Ltd., CF = CF ₂ and CF ₂ = CFO (CF ₂ ) ₃ -, with the cathode made of nickel-made expanded metal).
Copolymer with COOCH ₃ , ion exchange capacity
1.45meq/g resin) was used as an anode for alkaline water electrolysis with an ion exchange membrane, and the water electrolysis test was 15%.
The test was carried out using KOH, 110° C., and a current density of 70 A/dm ² . Table 1 shows the results of measuring oxygen overvoltage.

【table】

[Table] Comparative Examples 1 to 2 Comparative Example 1 was carried out according to Example 12 of JP-A-54-112785, and Comparative Example 2 was prepared by replacing NiCl ₂ 6H ₂ O in Example 12 of the same publication with CoCl ₂ . 6H ₂ O (concentration
300g/), Ni-Al and Co
-A plating electrode with dispersed Al alloy powder was manufactured. A part of the metal particles on the obtained electrode was peeled off and its composition was investigated. The results are also listed in Table 2. A water electrolysis test was conducted under the same conditions as in Examples 1 to 12.
The results are shown in Table 2. Comparative Examples 3 to 6 Anodes were manufactured in the same manner as in the example except that the composition of the alloy powder was changed to Comparative Examples 3 to 6 in Table 2.
Table 2 shows the results of a water electrolysis test conducted in the same manner as in the examples. Comparative Examples 3 and 4 show that no particular performance improvement is observed even when a large amount of the third component is added.
In Comparative Examples 5 and 6, the metal composition of the raw material powder was outside the preferred range, so the oxygen overvoltage was higher than originally.

[Table] Examples 13 to 16 Example 2, Example 4, Example 7, and Example 11
The electrode was used as an anode, the cathode was made of nickel expanded metal, and the diaphragm was made of ethylene and tetrafluoroethylene copolymer cloth (manufactured by Asahi Glass Co., Ltd.).
Accelerated durability tests were conducted on the electrode using five stacked COP sheets (approximately 100 meshes). current density
500A/dm ² , and the number of test days was 15 days. After the exam,
The increase in oxygen overpotential at a current density of 70 A/dm ² was investigated. +10mV, 0mV, + in numerical order of examples
It was 5mV and +5mV. Comparative Examples 7-8 Examples 13-16 for the electrodes of Comparative Examples 1 and 2
The same electrode acceleration durability test was conducted. The increased values of oxygen overvoltage were +60 mV and +70 mV, respectively.

[Brief explanation of the drawing]

Figure 1 is a diagram consisting of three components: X = Ni or Co, Y = Al, Zn, Mg or Si, and Z = noble metal or rhenium. The composition of the alloy with electrode activity for the anode is shown. FIG. 2 is a partial cross-sectional view of the surface of one example of the electrode of the present invention, and FIG. 3 is a partial cross-sectional view of the surface of another example of the electrode of the present invention. Figure 4 is a diagram consisting of three components: X = Ni or Co, Y = Al, Zn, Mg or Si, and Z = noble metal or rhenium.
The composition ranges enclosed by A', B', C', and D' indicate the composition range of the electrode active alloy used in the method of the present invention.

Claims (1)

[Scope of Claims] 1. An alloy consisting of a component X consisting of nickel and/or cobalt, a component Y selected from aluminum, zinc, magnesium, and silicon, and a component Z selected from noble metals and rhenium, wherein the component X,
An anode for water electrolysis made of an alloy in which Y and Z are in the range surrounded by points A, B, C, and D in FIG. A: X=99.6wt%, Y=0wt%, Z=0.4wt% B: X=79.6wt%, Y=20wt%, Z=0.4wt% C: X=40wt%, Y=20wt%, Z= 40wt% D: X = 40wt%, Y = 0wt%, Z = 60wt% 2 On the electrode core, component X consisting of nickel and/or cobalt, component Y selected from aluminum, zinc, magnesium, silicon, and noble metal,
An anode for water electrolysis, which is provided with a layer of an alloy consisting of a component Z selected from rhenium, in which the components X, Y, and Z are in the range surrounded by points A, B, C, and D in Figure 1. . A: X=99.6wt%, Y=0wt%, Z=0.4wt% B: X=79.6wt%, Y=20wt%, Z=0.4wt% C: X=40wt%, Y=20wt%, Z= 40wt% D: X = 40wt%, Y = 0wt%, Z = 60wt% 3 An alloy layer was formed with some of the alloy particles exposed on the surface of the layer provided on the electrode core. The anode for water electrolysis according to claim 2, which is a water electrolysis anode. 4 Component X consisting of nickel and/or cobalt, component Y selected from aluminum, zinc, and magnesium, and component Z selected from noble metals and rhenium are surrounded by points A', B', C', and D' in Figure 4. Electrode active metal particles made of an alloy within the range of 100% are uniformly dispersed in a plating bath, and co-electrodeposited onto the electrode core, or by coating, dipping, baking, or electroplating. A method for producing an anode for water electrolysis, characterized in that a uniform layer of the above-mentioned alloy is provided thereon. A′: X=59.8wt%, Y=40wt%, Z=0.2wt% B′: X=39.8wt%, Y=60wt%, Z=0.2wt% C′: X=5wt%, Y=60wt% , Z = 35wt% D': X = 12wt%, Y = 40wt%, Z = 48wt% 5. Water electrolysis according to claim 4, wherein the coating method is a method of spraying the alloy particles onto the electrode core. Manufacturing method for anodes. 6. The method for producing an anode for water electrolysis according to claim 4, wherein the immersion method is a method of immersing the electrode core in a molten liquid of the alloy. 7. The method for producing an anode for water electrolysis according to claim 4, wherein the electroplating method is an alloy plating method. 8. The method for producing an anode for water electrolysis according to claim 4, wherein the plating bath contains metal ions of the same type as component X. 9. The method for producing an anode for water electrolysis according to claim 4 or 8, wherein the plating bath has a pH of 1.5 to 3.0. 10 An alloy layer provided by co-electrodeposition, dipping, painting, baking or electroplating with a NaOH concentration of 10
~35% in caustic soda aqueous solution at temperature 10-50℃
The method for producing an anode for water electrolysis according to claim 4, wherein the treatment is performed for 0.5 to 3 hours.