JP2020117780A - Electrode for electrolysis and production method of electrode for electrolysis - Google Patents

Abstract

To improve an electric conductivity.SOLUTION: An electrode for electrolysis 1 comprises a titanium substrate 2, an intermediate layer 3, and a catalytic layer 6. The titanium substrate 2 includes a first principal plane 21 and a second principal plane 22. The intermediate layer 3 is formed on the first principal plane 21 side of the titanium substrate 2. The catalytic layer 6 is formed on the intermediate layer 3. The intermediate layer 3 includes a titanium oxide layer 4, a platinum layer 5, and a plurality of conductor parts 50. The titanium oxide layer 4 is formed on the first principal plane 21 of the titanium substrate 2. The platinum layer 5 is formed on the titanium oxide layer 4. The plurality of conductor parts 50, which extend into the titanium substrate 2 to penetrate through the titanium oxide layer 4 from the platinum layer 5, contact the titanium substrate 2.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an electrode for electrolysis and a method for manufacturing an electrode for electrolysis, and more particularly, to an electrode for electrolysis used for generating chlorine by electrolyzing salt water and a method for manufacturing the electrode for electrolysis.

BACKGROUND ART Conventionally, there is known a technique in which dilute saline solution obtained by adding salt to tap water is electrolyzed to generate chlorine, and hypochlorous acid is produced by a reaction between the chlorine and water (Patent Document 1).

Patent Document 1 discloses, as an electrode for electrolysis, an electrode substrate made of titanium or a titanium alloy, a titanium oxide layer provided on the electrode substrate, and iridium oxide provided on the titanium oxide layer in terms of metal. An intermediate oxide layer formed of a composite of 3 to 30 mol% and tantalum oxide 70 to 97 mol%, and 2 to 35 mol% of rhodium oxide and 30 iridium oxide in terms of metal, which are provided on the intermediate oxide layer. ˜80 mol %, tantalum oxide 6-35 mol% and platinum 12-62 mol %, a composite electrode.

JP, 2009-52069, A

The electrode for electrolysis described in Patent Document 1 has a laminated structure of a titanium oxide layer and an intermediate oxide layer between the electrode substrate and the composite (catalyst layer), so that the conductivity decreases. I will end up.

An object of the present disclosure is to provide an electrode for electrolysis and a method for manufacturing the electrode for electrolysis, which can improve conductivity.

An electrode for electrolysis according to an aspect of the present disclosure includes a titanium substrate, an intermediate layer, and a catalyst layer. The titanium substrate has a first main surface and a second main surface opposite to the first main surface. The intermediate layer is formed on the first main surface side of the titanium substrate. The catalyst layer is formed on the intermediate layer. The intermediate layer has a titanium oxide layer, a platinum layer, and a plurality of conductor portions. The titanium oxide layer is formed on the first main surface of the titanium substrate. The platinum layer is formed on the titanium oxide layer. The plurality of conductor portions extend from the platinum layer through the titanium oxide layer into the titanium substrate, and are in contact with the titanium substrate.

A method for manufacturing an electrode for electrolysis according to an aspect of the present disclosure includes an intermediate layer forming step and a catalyst layer forming step. In the intermediate layer forming step, an intermediate layer is formed on the first main surface side of a titanium substrate having a first main surface and a second main surface opposite to the first main surface. In the catalyst layer forming step, a catalyst layer is formed on the intermediate layer. The intermediate layer forming step includes a crack forming step, a titanium hydride film forming step, a coating step, and a heat treatment step. In the crack forming step, a plurality of microcracks extending from the first main surface of the titanium substrate into the titanium substrate are formed. In the titanium hydride film forming step, a titanium hydride film is formed extending over the first main surface of the titanium substrate and the inner peripheral surface of each of the plurality of microcracks in the titanium substrate. In the coating step, a solution containing a solvent and a platinum compound is coated on the titanium hydride film. In the heat treatment step, the platinum compound is thermally decomposed and the titanium hydride film is thermally decomposed by performing heat treatment of drying the solution in an atmosphere containing oxygen.

A method for manufacturing an electrode for electrolysis according to another aspect of the present disclosure includes an intermediate layer forming step and a catalyst layer forming step. In the intermediate layer forming step, an intermediate layer is formed on the first main surface side of a titanium substrate having a first main surface and a second main surface opposite to the first main surface. In the catalyst layer forming step, a catalyst layer is formed on the intermediate layer. The intermediate layer forming step includes a hole forming step, a crack forming step, a titanium hydride film forming step, a coating step, and a heat treatment step. In the hole forming step, a plurality of holes are formed in the first main surface of the titanium substrate. In the crack forming step, a plurality of microcracks extending from the inner peripheral surface of each of the plurality of holes into the titanium substrate is formed. In the titanium hydride film forming step, hydrogenation across the first main surface of the titanium substrate, the inner peripheral surface of each of the plurality of holes in the titanium substrate, and the inner peripheral surface of each of the plurality of microcracks. Form a titanium film. In the coating step, a solution containing a solvent and a platinum compound is coated on the titanium hydride film. In the heat treatment step, the platinum compound is thermally decomposed and the titanium hydride film is thermally decomposed by performing heat treatment of drying the solution in an atmosphere containing oxygen.

According to the electrolysis electrode and the method for producing the electrolysis electrode according to the above aspect of the present disclosure, it is possible to improve the conductivity.

FIG. 1A is a sectional view of an electrode for electrolysis according to the first embodiment. FIG. 1B is an enlarged view of a main part of FIG. 1A. 2A to 2C are process cross-sectional views for explaining the method for manufacturing the electrode for electrolysis according to the first embodiment. FIG. 3 is an explanatory diagram of a crack forming step in the method for producing an electrode for electrolysis described above. FIG. 4 is a process cross-sectional view for explaining a crack forming process in the method for producing an electrode for electrolysis described above. 5A to 5E are process cross-sectional views for explaining the intermediate layer forming process in the method for manufacturing an electrode for electrolysis described above. FIG. 6A is a cross-sectional view of the electrode for electrolysis according to the second embodiment. FIG. 6B is an enlarged view of a main part of FIG. 6A. 7A to 7C are process cross-sectional views for explaining the method for manufacturing the electrode for electrolysis according to the second embodiment. FIG. 8: is explanatory drawing of the hole formation process and crack formation process in the manufacturing method of the same electrode for electrolysis. FIG. 9 is a process cross-sectional view for explaining the hole forming step and the crack forming step in the above-described method for manufacturing an electrode for electrolysis. 10A to 10B are process cross-sectional views for explaining the intermediate layer forming process in the method for manufacturing an electrode for electrolysis described above. 11A to 11B are process cross-sectional views for explaining the intermediate layer forming process in the method for manufacturing an electrode for electrolysis described above.

1A, 1B, 2A to 2C, 3, 4, 5A to 5E, 6A, 6B, 7A to 7C, 8, 9, 10A, 10B, 11A and 11B described in the following first and second embodiments are schematic. It is a schematic diagram, and the ratio of the size and thickness of each constituent element in the diagram does not necessarily reflect the actual dimensional ratio.

(Embodiment 1)
(1.1) Overview Hereinafter, the electrolysis electrode 1 according to the first embodiment will be described with reference to FIGS. 1A and 1B.

The electrode 1 for electrolysis is an electrode used for generating chlorine by electrolyzing salt water. Here, the salt water is, for example, salt water. When the electrolysis electrode 1 is used for electrolyzing salt water, for example, by using the electrolysis electrode 1 as an anode of an anode and a cathode to which a direct current voltage is applied from a power source, salt water is electrolyzed to generate chlorine. Then, the reaction of chlorine with water can generate hypochlorous acid water.

The electrode 1 for electrolysis includes a titanium substrate 2, an intermediate layer 3, and a catalyst layer 6. The intermediate layer 3 is interposed between the titanium substrate 2 and the catalyst layer 6.

(1.2) Each component of the electrode for electrolysis Each component of the electrode for electrolysis 1 will be described in more detail below.

(1.2.1) Titanium Substrate The titanium substrate 2 has a first main surface 21 and a second main surface 22 opposite to the first main surface 21. The plan view shape of the titanium substrate 2 (outer peripheral shape when the titanium substrate 2 is viewed from the thickness direction D1 of the titanium substrate 2) is a rectangular shape. The thickness of the titanium substrate 2 is, for example, 100 μm or more and 2 mm or less, and is 500 μm as an example. The size of the titanium substrate 2 in plan view is, for example, 25 mm×60 mm.

The titanium substrate 2 is pure titanium, but may be doped with at least one impurity selected from palladium, nickel, ruthenium, tantalum, aluminum, and vanadium, for example.

(1.2.2) Catalyst Layer The catalyst layer 6 is formed on the intermediate layer 3. The electrode 1 for electrolysis has an interface between the catalyst layer 6 and the intermediate layer 3. That is, the catalyst layer 6 is provided on the titanium substrate 2 via the intermediate layer 3.

The catalyst layer 6 contains, for example, platinum and iridium. Iridium functions as a catalyst for generating chlorine. In the catalyst layer 6, iridium is dispersed in platinum.

(1.2.3) Intermediate Layer The intermediate layer 3 is formed on the first main surface 21 side of the titanium substrate 2.

The intermediate layer 3 has a titanium oxide layer 4, a platinum layer 5, and a plurality of conductor portions 50.

The titanium oxide layer 4 is formed on the first major surface 21 of the titanium substrate 2. The titanium oxide layer 4 has a film shape.

The platinum layer 5 is formed on the titanium oxide layer 4. The platinum layer 5 has a film shape.

The plurality of conductor portions 50 extend from the platinum layer 5 through the titanium oxide layer 4 into the titanium substrate 2, and are in contact with the titanium substrate 2. The material of each of the plurality of conductor portions 50 is platinum. The plurality of conductor portions 50 are continuous with the platinum layer 5. That is, the plurality of conductor portions 50 are formed integrally with the platinum layer 5. Thereby, in the electrode 1 for electrolysis, the platinum layer 5 is electrically connected to the titanium substrate 2 by the plurality of conductor portions 50.

Each of the plurality of conductor portions 50 includes a branch portion 51 and a plurality of contact portions 52. The branch portion 51 extends from the platinum layer 5 through the titanium oxide layer 4 into the titanium substrate 2 in a branch shape. The plurality of contact portions 52 branch from the branch portion 51, extend into the titanium substrate 2, and are in contact with the titanium substrate 2.

The intermediate layer 3 further includes a plurality of intervening portions 41. The plurality of intervening portions 41 extend from the titanium oxide layer 4 into the titanium substrate 2 along each of the plurality of branch portions 51. Each of the plurality of intervening portions 41 is interposed between the corresponding branch portion 51 among the plurality of branch portions 51 and the titanium substrate 2. The material of each of the plurality of interposition portions 41 is titanium oxide. The plurality of intervening portions 41 are continuous with the titanium oxide layer 4. That is, the plurality of intervening portions 41 are formed integrally with the titanium oxide layer 4.

In the electrode 1 for electrolysis, a part of the titanium oxide layer 4 is in contact with the catalyst layer 6.

(1.3) Method for Manufacturing Electrode for Electrolysis An example of a method for manufacturing the electrode 1 for electrolysis will be described based on FIGS. 2A to 2C, 3, 4 and 5A to 5E. Note that FIG. 5A is an enlarged view of a main part of FIG. 4.

In the method of manufacturing the electrode for electrolysis, the titanium substrate 2 is prepared as shown in FIG. 2A, and the intermediate layer forming step of forming the intermediate layer 3 on the first main surface 21 side of the titanium substrate 2 is performed as shown in FIG. 2B. After that, as shown in FIG. 2C, a catalyst layer forming step of forming the catalyst layer 6 on the intermediate layer 3 is performed.

In the intermediate layer forming step, the intermediate layer 3 is formed by sequentially performing a crack forming step, a titanium hydride film forming step, a coating step and a heat treatment step.

In the crack forming step, as shown in FIGS. 3, 4 and 5A, a plurality of microcracks 24 extending from the first main surface 21 of the titanium substrate 2 into the titanium substrate 2 are formed. Here, in the crack forming step, a plurality of micro cracks 24 are formed by an electric discharge machining method (EDM: Electrical Discharge Machining). The formation position of each of the plurality of microcracks 24 corresponds to the formation position of the corresponding branch portion 51 among the plurality of branch portions 51. The width of the microcracks 24 is, for example, 0.1 μm to 10 μm.

In the crack forming step, for example, as shown in FIG. 3, the EDM wire 9 is opposed to the first main surface 21 of the titanium substrate 2 so as to be substantially parallel to the electric spark 10 between the EDM wire 9 and the titanium substrate 2. By generating the micro cracks 24 in the titanium substrate 2. The arrow D1 in FIG. 3 indicates the moving direction of the EDM wire 9. That is, the EDM wire 9 is moved in the direction D1 along the first main surface 21 of the titanium substrate 2.

In the titanium hydride film forming step, as shown in FIG. 5B, the titanium hydride film 7 extending over the first main surface 21 of the titanium substrate 2 and the inner peripheral surface 241 of each of the plurality of microcracks 24 in the titanium substrate 2 is formed. Form. Here, in the titanium hydride film forming step, for example, hydrogenation is performed by hydrogenating a part of the titanium substrate 2 by hydrogenation with a chemical containing hydrogen fluoride, heat treatment in a hydrogen gas atmosphere, or hydrogen plasma treatment. The titanium film 7 is formed. The temperature of heat treatment (process temperature) in a hydrogen gas atmosphere is, for example, 300°C to 800°C. The process temperature when performing the hydrogen plasma treatment is, for example, room temperature (eg, 27° C.), but is not limited to this. In the case of hydrogen plasma treatment, the process temperature can be lowered as compared with the case of heat treatment in a hydrogen gas atmosphere.

In the coating step, as shown in FIG. 5C, a solution 8 containing a solvent and a platinum compound is coated on the titanium hydride film 7. The solution 8 is a solution in which a platinum compound is dissolved in a solvent. The solvent is, for example, a liquid obtained by mixing ethylene glycol monoethyl ether, hydrochloric acid and ethanol. The platinum compound is, for example, chloroplatinic acid, but not limited to this, and may be, for example, platinum chloride or the like.

In the heat treatment step, the platinum compound is thermally decomposed and the titanium hydride film 7 is thermally decomposed by performing a heat treatment of drying the solution 8 in an atmosphere containing oxygen. In the heat treatment step, the solution 8 is fired to form the platinum layer 5, the plurality of branch portions 51, and the plurality of contact portions 52 as shown in FIG. 5E. The dotted arrow in FIG. 5D schematically shows the path through which the solvent in the solution 8 evaporates in the heat treatment step. Further, in the heat treatment step, while generating H ₂ gas from the titanium hydride film 7, titanium oxide is generated by the reaction between oxygen and titanium, so that the titanium oxide layer 4 and the plurality of intervening layers are formed as shown in FIG. 5E. The part 41 is formed. The solid arrow in FIG. 5D schematically shows the moving path of H ₂ gas generated from the titanium hydride film 7 in the heat treatment step. Each of the titanium oxide layer 4 and the plurality of intervening portions 41 is formed to extend to a space formed by evaporation of the solvent in the solution 8, a space formed by generation of H ₂ gas from the titanium hydride film 7, and the like. Part of the titanium oxide layer 4 formed in the heat treatment step penetrates the platinum layer 5 and is exposed. Further, the contact portion 52 formed in the heat treatment process extends into the titanium substrate 2 through the intervening portion 41 that covers the corresponding branch portion 51 of the plurality of branch portions 51.

In the catalyst layer forming step, the catalyst layer 6 is formed by, for example, applying a solution containing a platinum compound and an iridium compound, which are bases of the catalyst layer 6, and baking the solution. The solution is, for example, a solution in which a platinum compound and an iridium compound are dissolved in a solvent. The solvent is, for example, a liquid obtained by mixing ethylene glycol monoethyl ether, hydrochloric acid and ethanol. The platinum compound is, for example, chloroplatinic acid, but not limited to this, and may be, for example, platinum chloride or the like. The iridium compound is, for example, iridium chloride, but is not limited to this, and may be, for example, iridium chloride, iridium nitrate, or the like. The firing conditions include a firing temperature and a firing time. The firing temperature is, for example, 500° C. to 700° C., and is 560° C. as an example. The firing time is, for example, 10 minutes to 20 minutes, and is 15 minutes as an example.

In the method for manufacturing an electrolysis electrode according to the first embodiment, the electrolysis electrode 1 can be obtained by completing the steps up to the catalyst forming step.

(1.4) Effects In the electrode 1 for electrolysis according to the first embodiment, the intermediate layer 3 is the titanium oxide layer 4 on the first main surface 21 of the titanium substrate 2, the platinum layer 5 on the titanium oxide layer 4, Since a part of each of the plurality of conductor portions 50 including the plurality of conductor portions 50 and extending from the platinum layer 5 into the titanium substrate 2 is in contact with the titanium substrate 2, conductivity can be improved.

Further, the electrode 1 for electrolysis according to the first embodiment extends from the titanium oxide layer 4 into the titanium substrate 2 along each of the plurality of branch portions 51, and each of the plurality of branch portions 51 corresponds to the corresponding branch portion. Corrosion resistance can be improved by further including a plurality of intervening portions 41 interposed between 51 and the titanium substrate 2.

(Embodiment 2)
(2.1) Overview Hereinafter, the electrolysis electrode 1a according to the second embodiment will be described with reference to FIGS. 6A and 6B.

The electrolysis electrode 1a according to the second embodiment is an electrode used for generating chlorine by electrolyzing salt water, like the electrolysis electrode 1 according to the first embodiment.

The electrode 1a for electrolysis includes a titanium substrate 2a, an intermediate layer 3a, and a catalyst layer 6a. The intermediate layer 3a is interposed between the titanium substrate 2a and the catalyst layer 6a.

(2.2) Components of Electrode for Electrolysis Each component of the electrode for electrolysis 1a will be described in more detail below.

(2.2.1) Titanium Substrate The titanium substrate 2a is similar to the titanium substrate 2 in the electrolysis electrode 1 according to the first embodiment, and the first main surface 21a and the second main surface on the side opposite to the first main surface 21a. And a surface 22a. The titanium substrate 2a has a rectangular shape in plan view.

The titanium substrate 2a is pure titanium, but may be doped with at least one impurity selected from palladium, nickel, ruthenium, tantalum, aluminum, and vanadium, for example.

(2.2.2) Catalyst Layer The catalyst layer 6a is formed on the intermediate layer 3a. The electrode 1a for electrolysis has an interface between the catalyst layer 6a and the intermediate layer 3a. That is, the catalyst layer 6a is provided on the titanium substrate 2a via the intermediate layer 3a.

The catalyst layer 6a includes, for example, platinum and iridium, like the catalyst layer 6 in the electrode 1 for electrolysis according to the first embodiment.

(2.2.3) Intermediate Layer The intermediate layer 3a is formed on the first main surface 21a side of the titanium substrate 2a.

The intermediate layer 3a has a titanium oxide layer 4a, a platinum layer 5a, and a plurality of conductor portions 50a.

The titanium oxide layer 4a is formed on the first major surface 21a of the titanium substrate 2a. The titanium oxide layer 4a has a film shape.

The platinum layer 5a is formed on the titanium oxide layer 4a. The platinum layer 5a (see FIG. 11B) has a film shape.

Each of the plurality of conductor portions 50a includes a protruding portion 53, a plurality of first contact portions 54, a plurality of branch portions 55, and a plurality of second contact portions 56. The material of each of the plurality of conductor portions 50a is platinum. The plurality of conductor portions 50a are continuous with the platinum layer 5a. That is, the plurality of conductor portions 50a are formed integrally with the platinum layer 5a. Thereby, in the electrode 1a for electrolysis, the platinum layer 5a is electrically connected to the titanium substrate 2 by the plurality of conductor portions 50a.

The plurality of protrusions 53 penetrate the titanium oxide layer 4a from the platinum layer 5a and protrude into the titanium substrate 2a. Each of the plurality of protrusions 53 has a tapered shape. Each of the plurality of protrusions 53 is formed over the entire length in the direction orthogonal to the paper surface of FIG. 6A.

The plurality of first contact portions 54 extend from the protruding portion 53 into the titanium substrate 2a and are in contact with the titanium substrate 2a.

The plurality of branch portions 55 extend from the protrusion 53 into the titanium substrate 2a in a branch shape.

The plurality of second contact portions 56 branch from each of the plurality of branch portions 55, extend into the titanium substrate 2a, and are in contact with the titanium substrate 2a. As a result, the plurality of second contact portions 56 are electrically connected to the titanium substrate 2a.

The intermediate layer 3a further includes a plurality of first interposition portions 43 and a plurality of second interposition portions 45.

The plurality of first intervening portions 43 extend into the titanium substrate 2a from the titanium oxide layer 4a along each of the plurality of protruding portions 53. Each of the plurality of first intervening portions 43 is interposed between the corresponding protruding portion 53 among the plurality of protruding portions 53 and the titanium substrate 2a. The material of each of the plurality of first interposition portions 43 is titanium oxide. The plurality of first intervening portions 43 are continuous with the titanium oxide layer 4a. That is, the plurality of first intervening portions 43 are formed integrally with the titanium oxide layer 4a.

The plurality of second intervening portions 45 extend from each of the first interposing portions 43 along each of the plurality of branch portions 55 into the titanium substrate 2a. Each of the plurality of second intervening portions 45 is interposed between the corresponding branch portion 55 among the plurality of branch portions 55 and the titanium substrate 2a. The material of each of the plurality of second interposition portions 45 is titanium oxide. The plurality of second intervening portions 45 are continuous with the corresponding first intervening portions 43.

(2.3) Method for manufacturing electrode for electrolysis A method for manufacturing the electrode 1a for electrolysis according to the second embodiment will be described below with reference to FIGS. 7A to 7C, 8, 9, 10A, 10B, 11A and 11B. The description of the same steps as those in the method of manufacturing the electrolysis electrode 1 according to the first embodiment will be appropriately omitted.

In the method for manufacturing an electrode for electrolysis, a titanium substrate 2a is prepared as shown in FIG. 7A, and an intermediate layer forming step of forming an intermediate layer 3a on the first main surface 21a side of the titanium substrate 2a is performed as shown in FIG. 7B. After that, as shown in FIG. 7C, a catalyst layer forming step of forming the catalyst layer 6a on the intermediate layer 3a is performed.

The intermediate layer forming step includes a hole forming step, a crack forming step, a titanium hydride film forming step, a coating step, and a heat treatment step.

In the hole forming step, a plurality of holes 25 (see FIGS. 8 and 9) corresponding to the plurality of protruding portions 53 one-to-one are formed in the first main surface 21a of the titanium substrate 2a. In the crack forming step, a plurality of microcracks 26 extending from the inner peripheral surface 251 of each of the plurality of holes 25 into the titanium substrate 2a is formed. In the hole forming step, a plurality of holes 25 are formed by the electric discharge machining method. Here, in the hole forming step, as shown in FIG. 8, for example, the hole 25 is formed by moving the EDM wire 9 from the first main surface 21a of the titanium substrate 2a in the direction D2 along the thickness direction of the titanium substrate 2a. Meanwhile, by generating electric sparks 10 between the EDM wire 9 and the titanium substrate 2a, the microcracks 26 are formed in the titanium substrate 2a from the inner peripheral surface 251 of the hole 25. In the hole forming step, the process of moving the EDM wire 9 in the direction D2 along the thickness direction of the titanium substrate 2a is performed by changing the relative positional relationship between the EDM wire 9 and the titanium substrate 2a in plan view. Repeat for a number of times. In the method of manufacturing the electrode for electrolysis according to the second embodiment, the hole forming step also serves as the crack forming step.

In the titanium hydride film forming step, as shown in FIG. 10A, the first main surface 21a of the titanium substrate 2a, the inner peripheral surface 251 of each of the plurality of holes 25 in the titanium substrate 2a and each of the plurality of microcracks 26 are formed. A titanium hydride film 7a extending over the peripheral surface 261 is formed. Here, in the titanium hydride film forming step, for example, hydrogenation is performed by hydrogenating a part of the titanium substrate 2a by hydrogenation with a chemical containing hydrogen fluoride, heat treatment in a hydrogen gas atmosphere, or hydrogen plasma treatment. The titanium film 7a is formed. The temperature of the heat treatment in the hydrogen gas atmosphere is, for example, 300°C to 800°C.

In the coating step, as shown in FIG. 10B, a solution 8a containing a solvent and a platinum compound is coated on the titanium hydride film 7a. The solution 8a is a solution in which a platinum compound is dissolved in a solvent. The solvent is, for example, a liquid obtained by mixing ethylene glycol monoethyl ether, hydrochloric acid and ethanol. The platinum compound is, for example, chloroplatinic acid, but not limited to this, and may be, for example, platinum chloride or the like.

In the heat treatment step, the platinum compound is thermally decomposed and the titanium hydride film 7a is thermally decomposed by performing a heat treatment of drying the solution 8a in an atmosphere containing oxygen. In the heat treatment step, the platinum layer 5a, the plurality of protruding portions 53, the plurality of first contact portions 54, the plurality of branch portions 55 and the plurality of second contact portions 56 are formed by baking the solution 8a (see FIG. 11B). ). The dotted arrow in FIG. 11A schematically shows the path through which the solvent in the solution 8a evaporates in the heat treatment step. Further, in the heat treatment step, while the H ₂ gas is generated from the titanium hydride film 7a, the titanium oxide layer 4a, the plurality of first intervening portions 43, and the plurality of first intervening portions 43 are generated by generating titanium oxide by the reaction of oxygen and titanium. The second interposition part 45 is formed (see FIG. 11B). The solid arrow in FIG. 11A schematically shows the moving path of the H ₂ gas generated from the titanium hydride film 7a in the heat treatment step. The titanium oxide layer 4a, the plurality of first intervening portions 43, and the plurality of second intervening portions 45 are spaces formed by evaporation of the solvent in the solution 8a, spaces formed by the generation of H ₂ gas from the titanium hydride film 7a, and the like. Is formed to extend to. The first contact portion 54 formed in the heat treatment process extends through the first intervening portion 43 that covers the corresponding protruding portion 53 and extends into the titanium substrate 2a. The second contact portion 56 formed in the heat treatment process extends through the second interposition portion 45 covering the corresponding branch portion 55 into the titanium substrate 2a.

In the catalyst layer forming step, for example, the catalyst layer 6a is formed by applying a solution containing a platinum compound and an iridium compound, which are the bases of the catalyst layer 6a, and baking the solution. The solution is, for example, a solution in which a platinum compound and an iridium compound are dissolved in a solvent. The solvent is, for example, a liquid obtained by mixing ethylene glycol monoethyl ether, hydrochloric acid and ethanol. The platinum compound is, for example, chloroplatinic acid, but not limited to this, and may be, for example, platinum chloride or the like. The iridium compound is, for example, iridium chloride, but is not limited to this, and may be, for example, iridium chloride, iridium nitrate, or the like. The firing conditions include a firing temperature and a firing time. The firing temperature is, for example, 500° C. to 700° C., and is 560° C. as an example. The firing time is, for example, 10 minutes to 20 minutes, and is 15 minutes as an example.

(2.4) Effects In the electrode for electrolysis 1a according to the second embodiment, the intermediate layer 3a is the titanium oxide layer 4a on the first major surface 21a of the titanium substrate 2a, and the platinum layer 5a is on the titanium oxide layer 4a. The plurality of conductor portions 50a and the plurality of conductor portions 50a extending from the platinum layer 5a into the titanium substrate 2a are in contact with the titanium substrate 2a, so that the conductivity can be improved.

Further, the electrolysis electrode 1a according to the second embodiment can further improve the corrosion resistance by further including the plurality of first interposition portions 43 and the plurality of second interposition portions 45.

Embodiments 1 and 2 are only one of the various embodiments of the present disclosure. The embodiments can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved.

For example, the plan view shape of the titanium substrate 2 in the electrolysis electrode 1 according to the first embodiment is not limited to a rectangular shape, and may be, for example, a square shape. The same applies to the titanium substrate 2a in the electrolysis electrode 1a according to the second embodiment.

In addition, in the electrode 1 for electrolysis according to the first embodiment, the catalyst layer 6 may include an oxide (for example, iridium oxide or the like). In the electrolysis electrode 1a according to the second embodiment, the catalyst layer 6a may include an oxide (for example, iridium oxide or the like), and a part of the titanium oxide layer 4a may be in contact with the catalyst layer 6a.

Further, in the electrode 1 for electrolysis according to the first embodiment, the intermediate layer 3 and the catalyst layer 6 are formed only on the first main surface 21 side of the titanium substrate 2, but the present invention is not limited to this, and the second electrode of the titanium substrate 2 is not limited thereto. The intermediate layer 3 and the catalyst layer 6 may also be formed on the main surface 22 side. In this case, the electrolysis electrode 1 includes a titanium substrate 2, two intermediate layers 3 and two catalyst layers 6. The titanium substrate 2 has a pair of main surfaces (first main surface 21 and second main surface 22). One of the two intermediate layers 3 is formed on the first main surface 21 side of the titanium substrate 2, and the other intermediate layer 3 is formed on the second main surface 22 side. The two catalyst layers 6 correspond one-to-one to the two intermediate layers 3 and are formed on the corresponding intermediate layers 3. The plurality of conductor portions 50 extend from the platinum layer 5 through the titanium oxide layer 4 into the titanium substrate 2, and are in contact with the titanium substrate 2. In the method of manufacturing the electrode 1 for electrolysis, the intermediate layer 3 is formed on each of the pair of main surfaces (the first main surface 21 and the second main surface 22) of the titanium substrate 2, and the catalyst is formed on each intermediate layer 3. Form layer 6. Similarly, in the electrolysis electrode 1a according to the second embodiment, the intermediate layer 3a and the catalyst layer 6a are formed only on the first main surface 21a side of the titanium substrate 2a, but the present invention is not limited to this. The intermediate layer 3a and the catalyst layer 6a may be formed also on the second main surface 22a side. In this case, in the method of manufacturing the electrode 1a for electrolysis, the intermediate layer 3a is formed on each of the pair of main surfaces (the first main surface 21a and the second main surface 22a) of the titanium substrate 2a, and each intermediate layer 3a is formed. The catalyst layer 6a is formed on top.

Further, in the method for manufacturing an electrode for electrolysis according to the first embodiment, for example, when the width of the microcracks 24 is relatively large (for example, 1 μm to 10 μm), titanium hydride is formed by the CVD method in the titanium hydride film forming step. The film 7 may be formed. Further, in the method for manufacturing the electrode for electrolysis according to the second embodiment, in the titanium hydride film forming step, for example, when the width of the microcracks 26 is relatively large (for example, 1 μm to 10 μm), titanium hydride is formed by the CVD method. The film 7a may be formed.

Further, in the method of manufacturing the electrode for electrolysis according to the second embodiment, in the hole forming step, the plurality of holes 25 are formed by utilizing the etching technique, the laser processing technique, etc., and the crack forming step after the hole forming step is performed. A plurality of microcracks 24 extending from the inner peripheral surface 251 of each of the plurality of holes 25 into the titanium substrate 2a may be formed by electrical discharge machining.

(Summary)
The following aspects are disclosed from the embodiments and the like described above.

The electrolysis electrode (1; 1a) according to the first aspect includes a titanium substrate (2; 2a), an intermediate layer (3; 3a), and a catalyst layer (6; 6a). The titanium substrate (2; 2a) has a first main surface (21; 21a) and a second main surface (22; 22a) opposite to the first main surface (21; 21a). The intermediate layer (3; 3a) is formed on the first main surface (21; 21a) side of the titanium substrate (2; 2a). The catalyst layer (6; 6a) is formed on the intermediate layer (3; 3a). The intermediate layer (3; 3a) has a titanium oxide layer (4; 4a), a platinum layer (5; 5a), and a plurality of conductor portions (50; 50a). The titanium oxide layer is formed on the first main surface (21; 21a) of the titanium substrate (2; 2a). The platinum layer (5; 5a) is formed on the titanium oxide layer (4; 4a). The plurality of conductor portions (50; 50a) extend from the platinum layer (5; 5a) through the titanium oxide layer (4; 4a) into the titanium substrate (2; 2a), and the titanium substrate (2; 2a). ).

In the electrode (1; 1a) for electrolysis according to the first aspect, it is possible to improve conductivity.

In the electrolysis electrode (1) according to the second aspect, in the first aspect, each of the plurality of conductor portions (50) includes a branch portion (51) and a plurality of contact portions (52). The branch portion (51) extends from the platinum layer (5) through the titanium oxide layer (4) into the titanium substrate (2) in a branch shape. The plurality of contact portions (52) branch from the branch portion (51), extend into the titanium substrate (2), and are in contact with the titanium substrate (2). The intermediate layer (3) further includes a plurality of intervening portions (41). The plurality of intervening portions (41) extend from the titanium oxide layer (4) along the plurality of branch portions (51) into the titanium substrate (2). Each of the plurality of intervening portions (41) is interposed between the corresponding branch portion (51) among the plurality of branch portions (51) and the titanium substrate (2).

In the electrode for electrolysis (1) according to the second aspect, it is possible to improve the corrosion resistance.

In the electrolysis electrode (1a) according to the third aspect, in the first aspect, each of the plurality of conductor portions (50a) includes a protrusion (53), a plurality of first contact portions (54), and a plurality of first contact portions (54). A branch portion (55) and a plurality of second contact portions (56). The protrusion (53) penetrates the titanium oxide layer (4a) from the platinum layer (5) and protrudes into the titanium substrate (2a). The plurality of first contact portions (54) extend from the protrusion (53) into the titanium substrate (2a) and are in contact with the titanium substrate (2a). The plurality of branch portions (55) extend in a branch shape from the protruding portion (53) into the titanium substrate (2a). The plurality of second contact portions (56) branch from each of the plurality of branch portions (55), extend into the titanium substrate (2a), and are in contact with the titanium substrate (2a). The intermediate layer (3a) further includes a plurality of first intervening portions (43) and a plurality of second intervening portions (45). The plurality of first intervening portions (43) extend from the titanium oxide layer (4a) into the titanium substrate (2a) along each of the plurality of protruding portions (53). Each of the plurality of first intervening portions (43) is interposed between the corresponding protrusion (53) of the plurality of protrusions (53) and the titanium substrate (2a). The plurality of second intervening portions (45) extend into the titanium substrate (2a) from each of the first intervening portions (43) along each of the plurality of branch portions (55). Each of the plurality of second interposition portions (45) is interposed between the corresponding branch portion (55) of the plurality of branch portions (55) and the titanium substrate (2a).

In the electrode (1a) for electrolysis according to the third aspect, it becomes possible to improve the corrosion resistance.

In the electrode (1; 1a) for electrolysis according to the fourth aspect, in any one of the first to third aspects, the catalyst layer (6; 6a) contains an oxide. A part of the titanium oxide layer (4; 4a) is in contact with the catalyst layer (6; 6a).

In the electrolysis electrode (1; 1a) according to the fourth aspect, it is possible to improve the adhesion between the catalyst layer (6; 6a) and the intermediate layer (3; 3a).

The method for producing an electrode for electrolysis according to the fifth aspect includes an intermediate layer forming step and a catalyst layer forming step. In the intermediate layer forming step, the titanium substrate (2) having the first main surface (21) and the second main surface (22) opposite to the first main surface (21) is provided on the first main surface (21) side. The intermediate layer (3) is formed. In the catalyst layer forming step, the catalyst layer (6) is formed on the intermediate layer (3). The intermediate layer forming step includes a crack forming step, a titanium hydride film forming step, a coating step, and a heat treatment step. In the crack forming step, a plurality of microcracks (24) extending from the first main surface (21) of the titanium substrate (2) into the titanium substrate (2) are formed. In the titanium hydride film forming step, titanium hydride that straddles the first main surface (21) of the titanium substrate (2) and the inner peripheral surface (241) of each of the plurality of microcracks (24) in the titanium substrate (2). Form a film (7). In the coating step, a solution (8) containing a solvent and a platinum compound is coated on the titanium hydride film (7). In the heat treatment step, the platinum compound is thermally decomposed and the titanium hydride film (7) is thermally decomposed by performing a heat treatment of drying the solution (8) in an atmosphere containing oxygen.

The electrolysis electrode manufacturing method according to the fifth aspect can improve conductivity.

In the method for manufacturing an electrode for electrolysis according to the sixth aspect, in the fifth aspect, in the crack forming step, a plurality of microcracks (24) are formed by an electric discharge machining method.

In the method of manufacturing an electrode for electrolysis according to the sixth aspect, a plurality of microcracks (24) can be easily formed.

The method for manufacturing an electrode for electrolysis according to the seventh aspect includes an intermediate layer forming step and a catalyst layer forming step. In the intermediate layer forming step, a titanium substrate (2a) having a first main surface (21a) and a second main surface (22a) opposite to the first main surface (21a) is provided on the first main surface (21a) side. The intermediate layer (3a) is formed. In the catalyst layer forming step, the catalyst layer (6a) is formed on the intermediate layer (3a). The intermediate layer forming step includes a hole forming step, a crack forming step, a titanium hydride film forming step, a coating step, and a heat treatment step. In the hole forming step, a plurality of holes (25) are formed in the first main surface (21a) of the titanium substrate (2a). In the crack forming step, a plurality of micro cracks (26) extending from the inner peripheral surface (251) of each of the plurality of holes (25) into the titanium substrate (2a) are formed. In the titanium hydride film forming step, the first main surface (21a) of the titanium substrate (2a), the inner peripheral surface (251) of each of the plurality of holes (25) in the titanium substrate (2a), and the plurality of microcracks (26). ), the titanium hydride film (7a) is formed so as to straddle each inner peripheral surface (261). In the coating step, a solution (8a) containing a solvent and a platinum compound is coated on the titanium hydride film (7a). In the heat treatment step, the platinum compound is thermally decomposed and the titanium hydride film (7a) is thermally decomposed by performing a heat treatment of drying the solution (8a) in an atmosphere containing oxygen.

In the method of manufacturing an electrode for electrolysis according to the seventh aspect, it is possible to improve conductivity.

In the method for manufacturing an electrode for electrolysis according to an eighth aspect, in the seventh aspect, in the hole forming step, a plurality of holes (25) are formed by an electric discharge machining method. The hole forming process also serves as a crack forming process.

In the method of manufacturing the electrode for electrolysis according to the eighth aspect, the plurality of holes (25) and the plurality of microcracks (26) can be formed in the same step.

A method for producing an electrode for electrolysis according to a ninth aspect is the method for producing an electrode for electrolysis according to any one of the fifth to eighth aspects, wherein in the titanium hydride film forming step, hydrogenation treatment with a chemical containing hydrogen fluoride or a hydrogen gas atmosphere is performed. Part of the titanium substrate (2; 2a) is hydrogenated by the heat treatment in step 1 or hydrogen plasma treatment to form a titanium hydride film (7; 7a).

In the method for manufacturing an electrode for electrolysis according to the ninth aspect, the titanium hydride film (7; 7a) can be easily formed.

1, 1a Electrode for electrolysis 2, 2a Titanium substrate 21, 21a First main surface 22, 22a Second main surface 24 Microcrack 241 Inner peripheral surface 25 Hole 251 Inner peripheral surface 26 Microcrack 261 Inner peripheral surface 3, 3a Intermediate layer 4, 4a Titanium oxide layer 41 Intervening part 43 First intervening part 45 Second intervening part 5, 5a Platinum layer 50, 50a Conductor part 51 Branch part 52 Contact part 53 Projection part 54 First contact part 55 Branch part 56 Second contact Part 6, 6a Catalyst layer 7, 7a Titanium hydride film 8, 8a Solution

Claims (9)

A titanium substrate having a first main surface and a second main surface opposite to the first main surface;
An intermediate layer formed on the first main surface side of the titanium substrate;
A catalyst layer formed on the intermediate layer,
The intermediate layer is
A titanium oxide layer formed on the first main surface of the titanium substrate;
A platinum layer formed on the titanium oxide layer,
A plurality of conductor portions which extend from the platinum layer through the titanium oxide layer into the titanium substrate and are in contact with the titanium substrate,
Electrode for electrolysis. Each of the plurality of conductor portions is
Branches extending from the platinum layer through the titanium oxide layer into the titanium substrate in a branch shape,
A plurality of contact portions that branch from the branch portion and extend into the titanium substrate and are in contact with the titanium substrate;
The intermediate layer is
A plurality of titanium oxide layers extending from the titanium oxide layer into the titanium substrate along each of the plurality of branches, each of which is interposed between the corresponding branch of the plurality of branches and the titanium substrate. Further includes an intervening part of
The electrode for electrolysis according to claim 1. Each of the plurality of conductor portions is
A protrusion protruding from the platinum layer into the titanium substrate through the titanium oxide layer,
A plurality of first contact portions extending from the protruding portion into the titanium substrate and in contact with the titanium substrate;
A plurality of branch portions extending in a branch shape from the protrusion into the titanium substrate;
A plurality of second contact portions that branch from each of the plurality of branch portions and extend into the titanium substrate and are in contact with the titanium substrate;
The intermediate layer is
A plurality of extending from the titanium oxide layer into the titanium substrate along each of the plurality of protrusions, each interposed between the corresponding protrusion of the plurality of protrusions and the titanium substrate; A first intervening part of
Each of the first intervening portions extends into the titanium substrate along each of the plurality of branch portions, and each of the first intervening portions is interposed between the corresponding branch portion of the plurality of branch portions and the titanium substrate. Further comprising a plurality of second intervening portions,
The electrode for electrolysis according to claim 1. The catalyst layer contains an oxide,
Part of the titanium oxide layer is in contact with the catalyst layer,
The electrode for electrolysis according to any one of claims 1 to 3. An intermediate layer forming step of forming an intermediate layer on the first main surface side of a titanium substrate having a first main surface and a second main surface opposite to the first main surface;
A catalyst layer forming step of forming a catalyst layer on the intermediate layer,
The intermediate layer forming step,
A crack forming step of forming a plurality of microcracks extending from the first main surface of the titanium substrate into the titanium substrate;
A titanium hydride film forming step of forming a titanium hydride film across the first main surface of the titanium substrate and the inner peripheral surface of each of the plurality of microcracks in the titanium substrate;
A coating step of coating a solution containing a solvent and a platinum compound on the titanium hydride film,
By performing a heat treatment to dry the solution in an atmosphere containing oxygen, while thermally decomposing the platinum compound, a heat treatment step of thermally decomposing the titanium hydride film,
Manufacturing method of electrode for electrolysis. In the crack forming step, the plurality of microcracks are formed by an electric discharge machining method,
The method for producing the electrode for electrolysis according to claim 5. An intermediate layer forming step of forming an intermediate layer on the first main surface side of a titanium substrate having a first main surface and a second main surface opposite to the first main surface;
A catalyst layer forming step of forming a catalyst layer on the intermediate layer,
The intermediate layer forming step,
A hole forming step of forming a plurality of holes in the first main surface of the titanium substrate;
A crack forming step of forming a plurality of microcracks extending from the inner peripheral surface of each of the plurality of holes into the titanium substrate,
A titanium hydride film forming a titanium hydride film extending over the first main surface of the titanium substrate, the inner peripheral surface of each of the plurality of holes in the titanium substrate, and the inner peripheral surface of each of the plurality of microcracks. Forming process,
A coating step of coating a solution containing a solvent and a platinum compound on the titanium hydride film,
By performing a heat treatment to dry the solution in an atmosphere containing oxygen, while thermally decomposing the platinum compound, a heat treatment step of thermally decomposing the titanium hydride film,
Manufacturing method of electrode for electrolysis. In the hole forming step, the plurality of holes are formed by an electric discharge machining method,
The hole forming step also serves as the crack forming step,
The method for manufacturing the electrode for electrolysis according to claim 7. In the titanium hydride film forming step, the titanium hydride film is formed by hydrogenating a part of the titanium substrate by hydrogenation treatment with a chemical containing hydrogen fluoride, heat treatment in a hydrogen gas atmosphere, or hydrogen plasma treatment. Form,
A method for manufacturing the electrode for electrolysis according to claim 5.

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