WO2023188704A1

WO2023188704A1 - Electrolysis electrode

Info

Publication number: WO2023188704A1
Application number: PCT/JP2023/001109
Authority: WO
Inventors: 健太細井; 宜弘伊藤; 直樹知念
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2022-03-29
Filing date: 2023-01-17
Publication date: 2023-10-05

Abstract

The present invention addresses the problem of providing an electrolysis electrode with which more chlorine can be generated and improved durability can be achieved. An electrolysis electrode (1) comprises a conductive substrate (2), an intermediate layer (3), and a catalyst layer (4). The conductive substrate (2) contains at least titanium. The intermediate layer (3) is provided on a first main surface (21) of the conductive substrate (2). The intermediate layer (3) contains platinum. The catalyst layer (4) is provided on the intermediate layer (3). The catalyst layer (4) contains platinum and iridium oxide. The intermediate layer (3) includes: a first intermediate layer (31) provided on the first main surface (21) of the conductive substrate (2); and a second intermediate layer (32) provided on the first intermediate layer (31). The first intermediate layer (31) contains platinum. The second intermediate layer (32) contains platinum. The second intermediate layer (32) is a porous layer. The first intermediate layer (31) is a denser layer than the second intermediate layer (32).

Description

Electrode for electrolysis

The present disclosure relates to an electrode for electrolysis, and more particularly, to an electrode for electrolysis containing iridium oxide and platinum.

Conventionally, an electrolytic electrode used to generate chlorine by electrolyzing salt water is known (Patent Document 1).

Patent Document 1 discloses a conductive substrate containing at least titanium, an intermediate layer provided on the conductive substrate and containing platinum, and a catalyst layer provided on the intermediate layer and containing platinum and iridium oxide. An electrode for electrolysis comprising the following is disclosed.

It is desired to improve the amount of chlorine generated and the durability of electrodes for electrolysis.

International Publication No. 2021/117311

An object of the present disclosure is to provide an electrode for electrolysis that can increase the amount of chlorine generated and improve the durability.

An electrode for electrolysis according to one aspect of the present disclosure includes a conductive substrate, an intermediate layer, and a catalyst layer. The conductive substrate has a first main surface and a second main surface opposite to the first main surface. The conductive substrate includes at least titanium. The intermediate layer is provided on the first main surface of the conductive substrate. The intermediate layer includes platinum. The catalyst layer is provided on the intermediate layer. The catalyst layer contains platinum and iridium oxide. The intermediate layer includes a first intermediate layer provided on the first main surface of the conductive substrate, and a second intermediate layer provided on the first intermediate layer. The first intermediate layer includes platinum. The second intermediate layer contains platinum. The second intermediate layer is a porous layer. The first intermediate layer is denser than the second intermediate layer.

FIG. 1 is a cross-sectional view of an electrode for electrolysis according to Embodiment 1. FIG. 2A is an explanatory diagram of main parts of the electrolytic electrode same as above. FIG. 2B is an explanatory diagram of particles contained in the catalyst layer of the electrolytic electrode same as above. FIG. 3 is a cross-sectional SEM image of a sample including a conductive substrate, a first intermediate layer, and a second intermediate layer. FIG. 4 is a cross-sectional view of the electrolysis electrode according to the second embodiment. FIG. 5 is a cross-sectional view of an electrode for electrolysis according to Embodiment 3. FIG. 6 is a plan view showing a first example of the pattern shape of the second intermediate layer in the electrode for electrolysis described above. FIG. 7 is a plan view showing a second example of the pattern shape of the second intermediate layer in the electrode for electrolysis described above. FIG. 8 is a plan view showing a third example of the pattern shape of the second intermediate layer in the electrode for electrolysis described above. FIG. 9 is a plan view showing a fourth example of the pattern shape of the second intermediate layer in the electrode for electrolysis described above. FIG. 10 is a cross-sectional view of an electrode for electrolysis according to Embodiment 4.

1 to 10 described in Embodiments 1 to 4 below are schematic diagrams, and the size and thickness ratios of each component in the diagrams do not necessarily reflect the actual dimensional ratios. Not necessarily.

(Embodiment 1)
Hereinafter, the electrolysis electrode 1 according to Embodiment 1 will be described based on FIGS. 1, 2A, 2B, and 3.

(1) Overview The electrolysis electrode 1 is an electrode used to generate chlorine by electrolyzing salt water. Here, the salt water is, for example, salt water. When the electrolytic electrode 1 is used for electrolyzing salt water, for example, by using the electrolytic electrode 1 as the anode of the anode and cathode to which a DC voltage is applied from the power supply, the salt water is electrolyzed to produce chlorine. can be generated, and hypochlorous acid water can be generated by the reaction between this chlorine and water.

(2) Components of Electrolyte for Electrolysis As shown in FIG. 1, the electrode for electrolysis 1 includes a conductive substrate 2, an intermediate layer 3, and a catalyst layer 4. Intermediate layer 3 is provided on conductive substrate 2 . The catalyst layer 4 is provided on the intermediate layer 3. That is, the intermediate layer 3 is a layer interposed between the conductive substrate 2 and the catalyst layer 4. Further, the electrolysis electrode 1 further includes a tantalum oxide layer 5 provided on the catalyst layer 4.

Hereinafter, each component of the electrolytic electrode 1 will be explained in more detail.

(2.1) Conductive Substrate The plan view shape of the conductive substrate 2 (the outer peripheral shape when the conductive substrate 2 is viewed from the thickness direction of the conductive substrate 2) is rectangular. The thickness of the conductive substrate 2 is, for example, 100 μm or more and 2 mm or less, and is, for example, 500 μm. The size of the conductive substrate 2 in plan view is, for example, 25 mm x 60 mm. The conductive substrate 2 has a first main surface 21 and a second main surface 22 opposite to the first main surface 21 . Further, the conductive substrate 2 has an outer circumferential surface 23 . The outer peripheral surface 23 of the conductive substrate 2 includes, for example, four side surfaces connecting the outer edge 210 of the first main surface 21 and the outer edge 220 of the second main surface 22 of the conductive substrate 2, and and does not include the second main surface 22.

The conductive substrate 2 contains at least titanium. The conductive substrate 2 is, for example, a titanium substrate. The material of the conductive substrate 2 is titanium or an alloy containing titanium as a main component (hereinafter referred to as titanium alloy). Examples of the titanium alloy include titanium-palladium alloy, titanium-nickel-ruthenium alloy, titanium-tantalum alloy, titanium-aluminum alloy, titanium-aluminum-vanadium alloy, and the like.

The first main surface 21 of the conductive substrate 2 is preferably a rough surface from the viewpoint of improving the adhesion of the intermediate layer 3. In the electrolysis electrode 1 according to the first embodiment, the first main surface 21 of the conductive substrate 2 is roughened before the intermediate layer 3 is provided. Here, regarding the surface roughness of the first main surface 21 of the conductive substrate 2, the arithmetic mean roughness Ra is, for example, 0.7 μm, and the maximum height Rz is 7 μm. The arithmetic mean roughness Ra and the maximum height Rz are defined in, for example, JIS B 0601-2001 (ISO 4287-1997). The arithmetic mean roughness Ra and the maximum height Rz are, for example, values measured from a cross-sectional SEM image (Cross-sectional Scanning Electron Microscope Image).

(2.2) Intermediate layer The intermediate layer 3 is provided on the first main surface 21 of the conductive substrate 2. Therefore, the electrolysis electrode 1 has an interface between the conductive substrate 2 and the intermediate layer 3. The intermediate layer 3 is preferably formed of a material that has higher corrosion resistance to salt water and chlorine than the conductive substrate 2. Moreover, from the viewpoint of increasing the electrical conductivity of the entire electrolytic electrode 1, the material of the intermediate layer 3 is preferably a material having electrical conductivity and high electrical conductivity. The material of the intermediate layer 3 is, for example, a transition metal or a mixture containing a transition metal, such as platinum, a mixture of tantalum, platinum, and iridium. The material of the intermediate layer 3 is platinum, for example.

The intermediate layer 3 includes a first intermediate layer 31 provided on the first main surface 21 of the conductive substrate 2 and a second intermediate layer 32 provided on the first intermediate layer 31. The material of the first intermediate layer 31 includes platinum. Further, the material of the second intermediate layer 32 includes platinum. Although the material of the first intermediate layer 31 and the material of the second intermediate layer are the same, at least one of the first intermediate layer 31 and the second intermediate layer 32 may further contain a material other than platinum. The second intermediate layer 32 is a porous layer. The first intermediate layer 31 is a denser layer than the second intermediate layer 32. The bulk density of the first intermediate layer 31 is greater than the bulk density of the second intermediate layer 32. FIG. 3 is a cross-sectional SEM image of a sample in which a first intermediate layer 31 is formed on the first main surface 21 of the conductive substrate 2, and a second intermediate layer 32 is formed on the first intermediate layer 31. In FIG. 3, it can be seen that the second intermediate layer 32 is a porous layer, and the first intermediate layer 31 is a denser layer than the second intermediate layer 32. As shown in FIG. 1, the second intermediate layer 32 has a plurality of pores 325 each having a size of 0.5 μm or more. The second intermediate layer 32 is a porous layer having continuous pores in which two or more of the plurality of pores 325 are connected. The first intermediate layer 31 is a non-porous layer, but may contain pores with a size of less than 0.5 μm.

In plan view from the thickness direction of the conductive substrate 2, the outer edge 320 of the second intermediate layer 32 is located inside the outer edge 310 of the first intermediate layer 31 and the outer edge 20 of the conductive substrate 2.

In the electrolysis electrode 1, the thickness of the second intermediate layer 32 is greater than the thickness of the first intermediate layer 31. The thickness of the first intermediate layer 31 is, for example, 0.01 μm or more and 10 μm or less. The thickness of the second intermediate layer 32 is, for example, 0.1 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less.

(2.3) Catalyst Layer As shown in FIG. 1, the catalyst layer 4 is provided on the intermediate layer 3. The electrolytic electrode 1 has an interface between a catalyst layer 4 and an intermediate layer 3. That is, the catalyst layer 4 is provided on the conductive substrate 2 with the intermediate layer 3 interposed therebetween.

The catalyst layer 4 contains platinum and iridium oxide. The catalyst layer 4 is a porous layer including a plurality of composite particles 41 and a plurality of pores 42, as shown in FIG. 2A. Each of the plurality of composite particles 41 includes platinum particles 411 and iridium oxide particles 412, as shown in FIG. 2B. In each of the plurality of composite particles 41, for example, a plurality of iridium oxide particles 412 are bonded to one platinum particle 411. In the catalyst layer 4, iridium oxide is dispersed by platinum. Iridium oxide functions as a catalyst to generate chlorine. In the catalyst layer 4, the molar ratio of platinum to iridium oxide is, for example, 8:5, but is not limited thereto. From the viewpoint of suppressing the aggregation of iridium that accompanies changes in the electrolytic electrode 1 over time due to use of the electrolytic electrode 1, the molar amount of iridium oxide is preferably equal to or less than the molar amount of platinum. The catalyst layer 4 may contain iridium in addition to platinum and iridium oxide. In this case, in the composite particles 41, iridium particles in addition to the iridium oxide particles 412 may be bonded to the platinum particles 411. Further, in the catalyst layer 4, the platinum particles 411 may be bonded to each other. The bonding state in the catalyst layer 4 is not particularly limited.

As shown in FIG. 1, the catalyst layer 4 has a plurality of recesses 45 recessed from the main surface 40 on the opposite side to the conductive substrate 2 side. In the electrolysis electrode 1, a portion of the catalyst layer 4 is exposed by the plurality of recesses 45. Each of the plurality of recesses 45 is, for example, a crack formed in the catalyst layer 4. More specifically, each of the plurality of recesses 45 is a linear crack when viewed from above in the thickness direction of the catalyst layer 4 . The shapes of the plurality of cracks (recesses 45) are different from each other. Each of the plurality of recesses 45 may be connected to at least one of the plurality of pores 42.

The depth of each of the plurality of recesses 45 is, for example, 0.1 μm or more. The depth of each of the plurality of recesses 45 may be a depth that reaches the intermediate layer 3 or may be a depth that does not reach the intermediate layer 3. In the electrolysis electrode 1 according to the first embodiment, the plurality of recesses 45 are not formed to penetrate the intermediate layer 3, and the entire first main surface 21 of the conductive substrate 2 is covered with the intermediate layer 3. ing. In plan view from the thickness direction of the conductive substrate 2, the width of each of the plurality of recesses 45 is 0.1 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 3 μm or less. The width of the recess 45 in a plan view from the thickness direction of the conductive substrate 2 is the opening width in the lateral direction (direction perpendicular to the longitudinal direction) on the main surface 40 of the catalyst layer 4. In plan view from the thickness direction of the conductive substrate 2, the length of each of the plurality of recesses 45 is shorter than the length of each side of the conductive substrate 2.

The thickness of the catalyst layer 4 is, for example, 0.1 μm to 10 μm.

In addition, in plan view from the thickness direction of the conductive substrate 2, the area of the main surface 40 of the catalyst layer 4 is set as S1, and the total area of the opening areas of each of the plurality of recesses 45 on the main surface 40 of the catalyst layer 4 is In the case of S2, the ratio of S2 to S1+S2 is, for example, 5% to 50%. The ratio of S2 to S1+S2 is preferably 5% or more from the viewpoint of improving chlorine generation efficiency. Further, the ratio of S2 to S1+S2 is preferably 50% or less, more preferably 20% or less, from the viewpoint of suppressing peeling of the catalyst layer 4. That is, it is more preferable that the ratio of S2 to S1+S2 is 5% or more and 20% or less.

(2.4) Tantalum Oxide Layer The tantalum oxide layer 5 has a function of suppressing elution of iridium oxide from the catalyst layer 4.

As shown in FIG. 2A, the tantalum oxide layer 5 includes a first portion 51 provided on the main surface 40 of the catalyst layer 4 and an inner surface 451 of at least one recess 45 among the plurality of recesses 45 in the catalyst layer 4. a second portion 52 provided thereon. Preferably, the tantalum oxide layer 5 has a second portion 52 on the inner surface 451 of each of the plurality of recesses 45 in the catalyst layer 4 .

(2.5) Tantalum Oxide Portion The electrolytic electrode 1 further includes a tantalum oxide portion 43 provided in at least one pore 42 among the plurality of pores 42 of the catalyst layer 4 and in contact with the catalyst layer 4 . The tantalum oxide portion 43 is formed, for example, when the tantalum oxide layer 5 is formed. The tantalum oxide portion 43 is in contact with the composite particles 41 of the catalyst layer 4.

(3) Method for manufacturing electrode for electrolysis A method for manufacturing electrode for electrolysis 1 will be briefly described.

In the method for manufacturing the electrolytic electrode 1, first, a conductive substrate 2 is prepared, and then a surface roughening step, a first intermediate layer forming step, a second intermediate layer forming step, a catalyst layer forming step, and a tantalum oxide layer forming step are performed. Perform the steps sequentially.

In the surface roughening step, the first main surface 21 of the conductive substrate 2 is roughened, for example, by immersing the conductive substrate 2 in an oxalic acid aqueous solution. The surface roughening step is not an essential step.

In the first intermediate layer forming step, the first intermediate layer 31 is formed on the first main surface 21 of the conductive substrate 2. In the first intermediate layer forming step, the first intermediate layer 31 is formed by applying a solution that is the source of the first intermediate layer 31, performing heat treatment, and then performing baking. The solution is a solution in which a platinum compound is dissolved in a solvent. The solvent is, for example, a liquid mixture of ethylene glycol monoethyl ether, hydrochloric acid, and ethanol. The platinum compound is, for example, chloroplatinic acid, but is not limited thereto, and may be, for example, platinum chloride. The method for forming the first intermediate layer 31 is not limited to the above-mentioned example, and may be, for example, a vapor deposition method, a sputtering method, a CVD method, a plating method, or the like.

In the second intermediate layer forming step, the second intermediate layer 32 is formed on the first intermediate layer 31. In the second intermediate layer forming step, the second intermediate layer 32 is formed by screen printing. In the second intermediate layer forming step, the second intermediate layer 32 made of a porous layer is formed by detaching the binder component that adjusts the viscosity of the material paste used in screen printing.

In the catalyst layer forming step, the catalyst layer 4 is formed on the intermediate layer 3 including the first intermediate layer 31 and the second intermediate layer 32. The catalyst layer forming process includes a first step and a second step.

In the first step of the catalyst layer forming process, at least one coating process and at least one drying process are performed to form a catalyst material layer on the intermediate layer 3 on the conductive substrate 2, which will become the source of the catalyst layer 4. form. The number of times of the coating process and the drying process is determined depending on the predetermined thickness of the catalyst layer 4, for example. Regarding the number of times of the coating process and drying process, the thicker the predetermined thickness of the catalyst layer 4, the more the number of times of the coating process and drying process may be increased. For example, in the catalyst layer forming step, the intermediate layer on the conductive substrate 2 is A catalyst material layer that will become the basis of the catalyst layer 4 is formed thereon.

In the first step of the catalyst layer forming process, a solution (hereinafter referred to as the first solution) containing a platinum compound and an iridium compound that will become the source of the catalyst layer 4 is directly or indirectly deposited on the intermediate layer 3 on the conductive substrate 2. ) is coated (after the coating process is performed), and then a heat treatment (drying process) of heating and drying under the first condition is performed at least once (e.g., 8 times), thereby removing the original structure of the catalyst layer 4. A layer of catalyst material is formed. The first solution is a solution in which a platinum compound and an iridium compound are dissolved in a solvent (hereinafter referred to as a first solvent). The first solvent is, for example, a liquid mixture of ethylene glycol monoethyl ether, hydrochloric acid, and ethanol. The platinum compound is, for example, chloroplatinic acid, but is not limited thereto, and may be, for example, platinum chloride. Chloroplatinic acid is, for example, hexachloroplatinic (IV) acid n-hydrate. The iridium compound is, for example, chloroiridic acid, but is not limited thereto, and may be, for example, iridium chloride or iridium nitrate. Chloroiridic acid is, for example, hexachloroiridic (IV) acid n-hydrate. The metal concentration (total concentration of platinum and iridium) of the first solution is, for example, 50 mg/mL. Further, the amount of the first solution applied is, for example, 2 μL/cm ² . The first condition includes a heat treatment temperature and a heat treatment time. The heat treatment temperature under the first condition is, for example, 100°C to 400°C, and is, for example, 220°C. Further, the heat treatment time under the first condition is, for example, 5 minutes to 15 minutes, and is 10 minutes as an example.

In the second step of the catalyst layer forming process, the catalyst layer 4 and a plurality of cracks (recesses 45) are formed by performing heat treatment to fire the catalyst material layer under predetermined firing conditions. The firing conditions include firing temperature and firing time. The firing temperature is, for example, 500°C to 700°C, and one example is 560°C. The firing time is, for example, 5 minutes to 20 minutes, and is 10 minutes as an example.

In the tantalum oxide layer forming step, a tantalum oxide layer 5 is formed on the catalyst layer 4. The tantalum oxide layer forming step includes a first step and a second step.

In the first step of the tantalum oxide layer process, a layer of material that will become the source of the tantalum oxide layer 5 is formed on the catalyst layer 4 by performing at least one coating process and at least one drying process. The number of times of the coating process and the drying process is determined depending on the predetermined thickness of the tantalum oxide layer 5, for example. Regarding the number of times of the coating process and drying process, the thicker the predetermined thickness of the tantalum oxide layer 5, the more the number of times of the coating process and drying process may be increased. For example, in the tantalum oxide layer forming step, the tantalum oxide layer 5 is formed on the catalyst layer 4 by performing the coating step a second prescribed number of times (for example, once) and the drying step the second prescribed number of times. Form a material layer.

In the first step of the tantalum oxide layer forming process, a solution containing a tantalum compound (hereinafter referred to as the second solution) that is the source of the tantalum oxide layer 5 is applied onto the catalyst layer 4 (after the application process is performed). By performing heat treatment (drying step) of heating and drying under the second condition at least once (for example, once), a material layer that becomes the source of the tantalum oxide layer 5 is formed. The second solution is a solution in which a tantalum compound is dissolved in a solvent (hereinafter referred to as a second solvent). The second solvent is, for example, a liquid mixture of ethylene glycol monoethyl ether, hydrochloric acid, and ethanol. The tantalum compound is, for example, tantalum chloride, but is not limited thereto, and may be, for example, tantalum ethoxide. The metal concentration (tantalum concentration) of the second solution is, for example, 50 mg/L. Further, the amount of the second solution applied is, for example, 1 μL/cm ² . The second conditions include heat treatment temperature and heat treatment time. The heat treatment temperature under the second condition is, for example, 100°C to 400°C, and is, for example, 220°C. Further, the heat treatment time under the second condition is, for example, 5 minutes to 15 minutes, and is, for example, 10 minutes.

In the second step of the tantalum oxide layer forming process, the tantalum oxide layer 5 is formed by performing heat treatment to fire the material layer under predetermined firing conditions. The firing conditions include firing temperature and firing time. The firing temperature is, for example, 500°C to 700°C, and one example is 560°C. The firing time is, for example, 5 minutes to 20 minutes, and is 10 minutes as an example.

In the method for manufacturing the electrolytic electrode 1 described above, the tantalum oxide portions 43 within the pores 42 in the catalyst layer 4 are formed in the tantalum oxide layer forming step.

Note that the surface roughening step, the first intermediate layer forming step, the second intermediate layer forming step, the catalyst layer forming step, and the tantalum oxide layer forming step are performed by providing a plurality of conductive substrates 2 and forming a plurality of conductive substrates 2. The process may be performed on a multi-chip board that can be removed. In this case, for example, a plurality of electrolytic electrodes 1 may be obtained by separating the multi-chip substrate into individual conductive substrates 2 after the tantalum oxide layer forming step.

(4) Summary The electrolysis electrode 1 according to the first embodiment includes a conductive substrate 2, an intermediate layer 3, and a catalyst layer 4. The conductive substrate 2 has a first main surface 21 and a second main surface 22 opposite to the first main surface 21 . Conductive substrate 2 contains at least titanium. Intermediate layer 3 is provided on first main surface 21 of conductive substrate 2 . Intermediate layer 3 contains platinum. The catalyst layer 4 is provided on the intermediate layer 3. Catalyst layer 4 contains platinum and iridium oxide. The intermediate layer 3 includes a first intermediate layer 31 provided on the first main surface 21 of the conductive substrate 2 and a second intermediate layer 32 provided on the first intermediate layer 31. The first intermediate layer 31 contains platinum. The second intermediate layer 32 contains platinum. The second intermediate layer 32 is a porous layer. The first intermediate layer 31 is a denser layer than the second intermediate layer 32. According to the electrolysis electrode 1 according to the first embodiment, it is possible to improve the amount of chlorine generated and to improve the durability. More specifically, in the electrolytic electrode 1, since the second intermediate layer 32 is a porous layer, the charge generated in iridium in the catalyst layer 4 is reduced compared to a case where the entire intermediate layer 3 is a dense layer. , it becomes possible to increase the movement route to the conductive substrate 2. In addition, in the electrolytic electrode 1, since the first intermediate layer 31 is a denser layer than the second intermediate layer 32, the intermediate layer 3 and the conductivity are more dense than the case where the entire intermediate layer 3 is a porous layer. The contact area with the substrate 2 can be increased, and the contact resistance between the intermediate layer 3 and the conductive substrate 2 can be reduced. Therefore, in the electrolytic electrode 1, the charges generated by the iridium in the catalyst layer 4 are easily transferred to the conductive substrate 2, so that the amount of chlorine generated can be improved. Further, in the electrolytic electrode 1, the first intermediate layer 31 of the intermediate layer 3 is provided on the first main surface 21 of the conductive substrate 2, thereby reducing the contact area between the intermediate layer 3 and the conductive substrate 2. Since it can be made larger and its adhesion can be improved, it is possible to improve its durability.

Further, the electrolysis electrode 1 according to the first embodiment includes the tantalum oxide layer 5 provided on the catalyst layer 4 containing platinum and iridium oxide, and a part of the catalyst layer 4 is exposed. It becomes possible to improve durability. Here, in the electrolysis electrode 1 according to the first embodiment, the catalyst layer 4 can contribute to the generation of chlorine, and the durability is improved compared to the case where the entire main surface 40 of the catalyst layer 4 is in contact with salt water. becomes possible. By including the tantalum oxide layer 5 and the tantalum oxide portion 43, the electrolytic electrode 1 according to the first embodiment can suppress excessive consumption (elution) of platinum iridium in the catalyst layer 4 during use. It is possible to suppress the occurrence of rapid structural changes in the layer 4, and it is also possible to suppress partial detachment of the catalyst layer 4 and peeling of the catalyst layer 4. Further, the electrolysis electrode 1 according to the first embodiment can suppress aggregation of iridium.

Furthermore, the electrolysis electrode 1 according to the first embodiment has tantalum oxide parts 43 provided in the plurality of pores 42 of the catalyst layer 4 and in contact with the catalyst layer 4, thereby increasing the mechanical strength of the catalyst layer 4. In addition, it becomes possible to suppress excessive consumption of iridium oxide, aggregation of iridium oxide, etc.

(Embodiment 2)
As shown in FIG. 4, the electrolytic electrode 1A according to the second embodiment has a first intermediate layer 31 provided over the first main surface 21, the outer circumferential surface 23, and the second main surface 22 of the conductive substrate 2. This is different from the electrolysis electrode 1 according to the first embodiment in that the electrode 1 is different from the electrode 1 for electrolysis according to the first embodiment. Regarding the electrolysis electrode 1A according to Embodiment 2, the same components as those of the electrolysis electrode 1 according to Embodiment 1 are given the same reference numerals, and the description thereof will be omitted.

In the electrolytic electrode 1A, the first intermediate layer 31 includes a portion 311 that covers at least a portion of the outer circumferential surface 23 of the conductive substrate 2 (the entire outer circumferential surface 23 in the example of FIG. It further includes a portion 312 that covers at least a portion of the main surface 22. In the electrolysis electrode 1A shown in FIG. 4, the portion 312 of the first intermediate layer 31 covers a part of the second main surface 22 of the conductive substrate 2, but does not cover the entire second main surface 22. It's okay.

In addition, in the electrolysis electrode 1A, the catalyst layer 4 also covers a portion 311 that covers the outer peripheral surface 23 of the conductive substrate 2 in the first intermediate layer 31, and the catalyst layer 4 also covers the portion 311 that covers the outer circumferential surface 23 of the conductive substrate 2. The outer edge 400 of the main surface 40 of the catalyst layer 4 is located outside the outer edge 310 of the first intermediate layer 31.

Further, the tantalum oxide layer 5 covers not only the main surface 40 of the catalyst layer 4 but also the outer peripheral surface 46 of the catalyst layer 4.

The electrolysis electrode 1A increases the contact area between the first intermediate layer 31 and the conductive substrate 2 by further including a portion 311 in which the first intermediate layer 31 covers at least a portion of the outer peripheral surface 23 of the conductive substrate 2. It becomes possible to do so.

Further, the electrolytic electrode 1A has a structure in which the first intermediate layer 31 further includes a portion 312 that covers at least a portion of the second main surface 22 of the conductive substrate 2, so that the first intermediate layer 31 and the conductive substrate 2 are separated from each other. It becomes possible to further increase the contact area.

(Embodiment 3)
As shown in FIG. 5, the electrolytic electrode 1B according to the third embodiment is different from the electrolytic electrode 1B according to the first embodiment in that the second intermediate layer 32 is formed in a predetermined pattern and has a plurality of porous parts 323. Different from electrode 1. Regarding the electrolysis electrode 1B according to Embodiment 3, the same components as those of the electrolysis electrode 1 according to Embodiment 1 are given the same reference numerals, and the description thereof will be omitted.

Each of the plurality of porous parts 323 contains porous platinum. Each of the plurality of porous parts 323 is linear when viewed from the thickness direction of the conductive substrate 2. The plurality of porous portions 323 are arranged in stripes on the first intermediate layer 31. In other words, the second intermediate layer 32 has a striped pattern portion P1. The plurality of porous parts 323 are arranged at equal intervals in the first direction D1. The term "equal intervals" as used herein does not necessarily have to be exactly the same interval, but may be any interval within a prescribed range (80% or more and 120% or less of the prescribed distance). The first direction D1 is a direction perpendicular to the thickness direction of the conductive substrate 2 when viewed from the thickness direction of the conductive substrate 2. The longitudinal direction of the plurality of porous parts 323 is a second direction orthogonal to the thickness direction of the conductive substrate 2 and the first direction D1. The width L1 of each porous portion 323 in the first direction D1 is, for example, 10 μm or more and 5 mm or less. Further, the distance SP1 between two adjacent porous portions 323 in the first direction D1 is, for example, 10 μm or more and 100 μm or less.

In the electrolysis electrode 1B according to the third embodiment, since the second intermediate layer 32 includes the striped pattern portion P1, it is possible to increase the contact area between the intermediate layer 3 and the catalyst layer 4.

The second intermediate layer 32 may be formed in any of the pattern shapes shown in FIGS. 6 to 9 as the pattern shape seen from the thickness direction of the conductive substrate 2. In FIGS. 6 to 9, the second intermediate layer 32 is hatched with dots, but these hatchings do not represent the cross section, but rather represent the pattern shape of the second intermediate layer 32 on the first intermediate layer 31. It is only added for ease of viewing.

In the first example shown in FIG. 6, the second intermediate layer 32 includes a plurality of porous parts 323 included in the striped pattern part P1 and a rectangular frame-shaped porous part surrounding the striped pattern part P1. 324. The plurality of porous parts 323 are connected to a rectangular frame-shaped porous part 324. Although the second intermediate layer 32 in the first example shown in FIG. 6 has a rectangular frame-shaped porous portion 324, it may have a configuration that does not have this porous portion 324.

In the second example shown in FIG. 7, the second intermediate layer 32 includes a lattice-shaped pattern portion P2 and a rectangular frame-shaped porous portion 324 surrounding the lattice-shaped pattern portion P2. The pattern portion P2 includes a grid-like porous portion 323. Although the second intermediate layer 32 in the second example shown in FIG. 7 has a rectangular frame-shaped porous portion 324, it may have a configuration that does not have this porous portion 324.

In the third example shown in FIG. 8, the second intermediate layer 32 includes a pattern portion P3 including a plurality of porous portions 323 arranged in a two-dimensional array, and a rectangular frame-shaped porous portion 324. . In plan view from the thickness direction of the conductive substrate 2, each of the plurality of porous parts 323 has a square shape. The length of each side of the plurality of porous parts 323 is 5 μm or more and 5 mm or less. Further, the distance between two adjacent porous portions 323 is, for example, 10 μm or more and 100 μm or less. Although the second intermediate layer 32 in the third example shown in FIG. 8 has a rectangular frame-shaped porous portion 324, it may have a configuration that does not have this porous portion 324. Further, each of the plurality of porous portions 323 is not limited to a square shape, and may be, for example, circular. In this case, the radius of the plurality of porous parts 323 is, for example, 2.5 μm or more and 2.5 mm or less.

In the fourth example shown in FIG. 9, the second intermediate layer 32 includes a rectangular pattern portion P0, a pattern portion P1, a pattern portion P2, and a pattern portion P3. In the fourth example shown in FIG. 9, pattern portion P0, pattern portion P1, pattern portion P2, and pattern portion P3 are arranged in the order of pattern portion P0, pattern portion P1, pattern portion P2, and pattern portion P3. Not limited to.

(Embodiment 4)
As shown in FIG. 10, the electrolytic electrode 1C according to the fourth embodiment has a first intermediate layer 31 provided over the first main surface 21, the outer peripheral surface 23, and the second main surface 22 of the conductive substrate 2. This is different from the electrolysis electrode 1B according to the third embodiment in that the electrode 1B is different from the electrode 1B for electrolysis according to the third embodiment. Regarding the electrolysis electrode 1C according to Embodiment 4, the same components as those of the electrolysis electrode 1B according to Embodiment 3 are given the same reference numerals, and the description thereof will be omitted.

In the electrolytic electrode 1C, the first intermediate layer 31 includes a portion 311 that covers at least a portion of the outer circumferential surface 23 of the conductive substrate 2 (in the example of FIG. 2 further includes a portion 312 that covers at least a portion of the second main surface 22. In the electrolysis electrode 1C shown in FIG. 10, the portion 312 of the first intermediate layer 31 covers a part of the second main surface 22 of the conductive substrate 2, but does not cover the entire second main surface 22. It's okay.

In addition, in the electrolysis electrode 1C, the catalyst layer 4 also covers a portion 311 covering the outer circumferential surface 23 of the conductive substrate 2 in the first intermediate layer 31, and in a plan view from the thickness direction of the conductive substrate 2. , the outer edge 400 of the main surface 40 of the catalyst layer 4 is located outside the outer edge 310 of the first intermediate layer 31 .

The electrolytic electrode 1C further includes a portion 311 in which the first intermediate layer 31 covers at least a portion of the outer peripheral surface 23 of the conductive substrate 2, thereby increasing the contact area between the first intermediate layer 31 and the conductive substrate 2. It becomes possible to do so.

Further, the electrolytic electrode 1C has a structure in which the first intermediate layer 31 further includes a portion 312 that covers at least a portion of the second main surface 22 of the conductive substrate 2, so that the first intermediate layer 31 and the conductive substrate 2 are separated from each other. It becomes possible to further increase the contact area.

(Modified example)
Embodiments 1-4 are just one of various embodiments of the present disclosure. Embodiments 1 to 4 can be modified in various ways depending on the design, etc., as long as the objective of the present disclosure can be achieved.

For example, the plan view shape of the conductive substrate 2 is not limited to a rectangular shape, but may be, for example, a square shape. Further, the shape of the conductive substrate 2 in plan view is not limited to a rectangular shape (rectangular shape, square shape), and may be any shape, for example, a circular shape.

Further, in the

electrolytic electrodes

1, 1A, 1B, and 1C, the thickness of the second intermediate layer 32 may be the same as the thickness of the first intermediate layer 31, or the thickness of the second intermediate layer 32 may be It may be thinner than the thickness of the first intermediate layer 31.

In addition, in the electrolytic electrodes 1 and 1B, in a plan view from the thickness direction of the conductive substrate 2, the outer edge 320 of the second intermediate layer 32, the outer edge 310 of the first intermediate layer 31, and the outer edge 20 of the conductive substrate 2 may overlap.

In the

electrolysis electrodes

1A and 1C, the first intermediate layer 31 includes a portion 311 that covers at least a portion of the outer peripheral surface 23 of the conductive substrate 2 and a portion that covers at least a portion of the second main surface 22 of the conductive substrate 2. 312, but may not include the portion 312 that covers at least a portion of the second main surface 22 of the conductive substrate 2.

Furthermore, the catalyst layer 4 is not limited to being a porous layer, and may be a non-porous layer.

Furthermore, the shapes of the plurality of recesses 45 may be the same. In this case, for example, in the method for manufacturing the electrolysis electrode 1, the plurality of recesses 45 may be formed using etching technology, laser processing technology, or the like. Utilizing these techniques has the advantage of increasing the degree of freedom in designing the layout and size of the plurality of recesses 45, and increasing the reproducibility of the formation positions of the plurality of recesses 45.

Further, in the

electrolysis electrodes

1, 1A, 1B, and 1C, the plurality of recesses 45 may not be provided in the catalyst layer 4; in this case, for example, the tantalum oxide layer 5 may It suffices to have a plurality of holes (for example, pinholes or cracks) that expose parts.

Further, in the

electrolysis electrodes

1, 1A, 1B, and 1C, even if the catalyst layer 4 is provided with a plurality of recesses 45, the tantalum oxide layer 5 has a plurality of cracks that expose a part of the catalyst layer 4. may be formed. In the method for manufacturing the electrolytic electrode 1 described above, when the thickness of the tantalum oxide layer 5 is 50 nm or more, cracks that expose a part of the catalyst layer 4 in the tantalum oxide layer 5 occur in the second step of the tantalum oxide layer forming process. may be formed. Further, in the method for manufacturing the electrolytic electrode 1 described above, cracks are formed in the tantalum oxide layer 5 in the second step of the tantalum oxide layer forming process, and cracks connected to the cracks in the tantalum oxide layer 5 are formed in the catalyst layer 4. Sometimes it is done. The plurality of holes in the tantalum oxide layer 5 may be formed using etching technology, laser processing technology, or the like.

The

electrolysis electrodes

1, 1A, 1B, and 1C may include a titanium oxide layer interposed between the conductive substrate 2 and the intermediate layer 3.

The tantalum oxide layer 5 may contain tantalum in addition to tantalum oxide. In other words, the tantalum oxide layer 5 may be a layer in which tantalum oxide and tantalum are mixed.

Further, the

electrolytic electrodes

1, 1A, 1B, and 1C are structures including an intermediate layer 3, a catalyst layer 4, and a tantalum oxide layer 5 on the second main surface 22 of the conductive substrate 2 on the first main surface 21 side. It may further include a structure similar to the above.

(summary)
From Embodiments 1 to 4 described above, the following aspects are disclosed in this specification.

The electrolysis electrode (1; 1A; 1B; 1C) according to the first aspect includes a conductive substrate (2), an intermediate layer (3), and a catalyst layer (4). The conductive substrate (2) has a first main surface (21) and a second main surface (22) opposite to the first main surface (21). The conductive substrate (2) contains at least titanium. The intermediate layer (3) is provided on the first main surface (21) of the conductive substrate (2). The intermediate layer (3) contains platinum. The catalyst layer (4) is provided on the intermediate layer (3). The catalyst layer (4) contains platinum and iridium oxide. The intermediate layer (3) includes a first intermediate layer (31) provided on the first main surface (21) of the conductive substrate (2) and a first intermediate layer (31) provided on the first intermediate layer (31). 2 intermediate layers (32). The first intermediate layer (31) contains platinum. The second intermediate layer (32) contains platinum. The second intermediate layer (32) is a porous layer. The first intermediate layer (31) is a denser layer than the second intermediate layer (32).

According to the electrolysis electrode (1; 1A; 1B; 1C) according to the first aspect, it is possible to improve the amount of chlorine generated and to improve the durability.

In the electrolytic electrode (1; 1A; 1B; 1C) according to the second aspect, in the first aspect, the second intermediate layer (32) is The outer edge (320) is located inside the outer edge (310) of the first intermediate layer (31) and the outer edge (20) of the conductive substrate (2).

According to the electrolytic electrode (1; 1A; 1B; 1C) according to the second aspect, it is possible to improve the uniformity of the thickness of the second intermediate layer (32), and the second intermediate layer ( 32) It becomes possible to reduce the amount of materials used.

In the electrolysis electrode (1; 1A; 1B; 1C) according to the third aspect, in the first or second aspect, the thickness of the second intermediate layer (32) is greater than the thickness of the first intermediate layer (31). big.

According to the electrolytic electrode (1; 1A; 1B; 1C) according to the third aspect, it is possible to improve durability.

According to the electrolysis electrode (1A; 1C) according to the fourth aspect, in any one of the first to third aspects, the conductive substrate (2) has an outer edge (210 ) and the outer edge (220) of the second main surface (22). The first intermediate layer (31) further includes a portion (311) that covers at least a portion of the outer peripheral surface (23) of the conductive substrate (2).

According to the electrolysis electrode (1A; 1C) according to the fourth aspect, it is possible to increase the contact area between the first intermediate layer (31) and the conductive substrate (2).

In the electrolytic electrode (1A; 1C) according to the fifth aspect, in the fourth aspect, the first intermediate layer (31) covers at least a portion of the second main surface (22) of the conductive substrate (2). It further includes a covering portion (312).

According to the electrolysis electrode (1A; 1C) according to the fifth aspect, it is possible to further increase the contact area between the first intermediate layer (31) and the conductive substrate (2).

In the electrolytic electrode (1B; 1C) according to the sixth aspect, in any one of the first to fifth aspects, the second intermediate layer (32) includes a striped pattern portion (P1).

In the electrolysis electrode (1B; 1C) according to the sixth aspect, it is possible to increase the contact area between the intermediate layer (3) and the catalyst layer (4).

In the electrolysis electrode (1B, 1C) according to the seventh aspect, in any one of the first to sixth aspects, the second intermediate layer (32) includes a lattice-like pattern portion (P2).

In the electrolysis electrode (1B; 1C) according to the seventh aspect, it is possible to increase the contact area between the intermediate layer (3) and the catalyst layer (4).

In the electrolysis electrode (1B; 1C) according to the eighth aspect, in any one of the first to seventh aspects, the second intermediate layer (32) includes a plurality of porous layers arranged in a two-dimensional array. The pattern portion (P3) includes a pattern portion (323).

In the electrolysis electrode (1B; 1C) according to the eighth aspect, it is possible to increase the contact area between the intermediate layer (3) and the catalyst layer (4).

The electrolytic electrode (1; 1A; 1B; 1C) according to the ninth aspect, in any one of the first to eighth aspects, further includes a tantalum oxide layer (5). A tantalum oxide layer (5) is provided on the catalyst layer (4). In the electrolysis electrodes (1; 1A; 1B; 1C), a part of the catalyst layer (4) is exposed.

In the electrolysis electrode (1; 1A; 1B; 1C) according to the ninth aspect, it is possible to improve durability.

In the electrolysis electrode (1; 1A; 1B; 1C) according to the tenth aspect, in the ninth aspect, the catalyst layer (4) includes platinum (platinum particles 411) and iridium oxide (iridium oxide particles 412), respectively. The porous layer includes a plurality of composite particles (41) including a plurality of composite particles (41) and a plurality of pores (42). The electrolytic electrode (1; 1A; 1B; 1C) further includes a tantalum oxide part (43) provided in at least one pore (42) among the plurality of pores (42) and in contact with the catalyst layer (4). .

In the electrolysis electrode (1; 1A; 1B; 1C) according to the tenth aspect, it is possible to improve the chlorine generation efficiency while improving the durability.

In the electrolysis electrode (1; 1A; 1B; 1C) according to the eleventh aspect, in the ninth or tenth aspect, the catalyst layer (4) has a main surface ( It has a plurality of recesses (45) recessed from 40). The tantalum oxide layer (5) has a first portion (51) provided on the main surface (40) of the catalyst layer (4) and at least one of the plurality of recesses (45) in the catalyst layer (4). a second portion (52) provided on the inner surface (451) of the recess (45).

In the electrolytic electrode (1; 1A; 1B; 1C) according to the eleventh aspect, it is possible to improve the chlorine generation efficiency while improving the durability.

In the twelfth aspect of the electrolysis electrode (1; 1A; 1B; 1C), in the eleventh aspect, the catalyst layer (4) is partially exposed by the plurality of recesses (45). ing.

In the electrolysis electrode (1; 1A; 1B; 1C) according to the twelfth aspect, salt water flows into the catalyst layer (4) from the inner surface (451) of the recess (45) exposed by the recess (45). (4) It becomes easier to penetrate in the in-plane direction. As a result, in the electrolysis electrode (1; 1A; 1B; 1C) according to the twelfth aspect, it is assumed that the catalyst layer (4) can more easily contribute to chlorine generation, making it possible to improve durability. .

In the electrolysis electrode (1; 1A; 1B; 1C) according to the thirteenth aspect, in any one of the first to twelfth aspects, the first main surface (21) of the conductive substrate (2) has a rough surface. It is a surface.

In the electrolysis electrode (1; 1A; 1B; 1C) according to the thirteenth aspect, it is possible to improve the adhesion between the conductive substrate (2) and the intermediate layer (3), and the catalyst layer (4) It becomes possible to suppress peeling from the conductive substrate (2) side, and it becomes possible to improve durability.

1, 1A; 1B; 1C Electrolysis electrode 2 Conductive substrate 20 Outer edge 21 First main surface 210 Outer edge 22 Second main surface 220 Outer edge 23 Outer peripheral surface 3 Intermediate layer 31 First intermediate layer 310 Outer edge 311 Part 312 Part 32 Second Intermediate layer 320 Outer edge 323 Porous part 4 Catalyst layer 40 Main surface 41 Composite particle 411 Platinum particle 412 Iridium oxide particle 42 Pore 43 Tantalum oxide part 45 Recessed part 451 Inner surface 5 Tantalum oxide layer 51 First part 52 Second part P1 Pattern part P2 Pattern section P3 Pattern section

Claims

a conductive substrate having a first main surface and a second main surface opposite to the first main surface, and containing at least titanium;
an intermediate layer provided on the first main surface of the conductive substrate and containing platinum;
a catalyst layer provided on the intermediate layer and containing platinum and iridium oxide,
The intermediate layer is
a first intermediate layer provided on the first main surface of the conductive substrate and containing platinum;
a second intermediate layer provided on the first intermediate layer and containing platinum;
The second intermediate layer is a porous layer,
The first intermediate layer is a denser layer than the second intermediate layer.
Electrode for electrolysis.
In plan view from the thickness direction of the conductive substrate, the outer edge of the second intermediate layer is located inside the outer edge of the first intermediate layer and the outer edge of the conductive substrate.
The electrode for electrolysis according to claim 1.
the thickness of the second intermediate layer is greater than the thickness of the first intermediate layer;
The electrode for electrolysis according to claim 1 or 2.
The conductive substrate further has an outer peripheral surface connecting an outer edge of the first main surface and an outer edge of the second main surface,
The first intermediate layer further includes a portion that covers at least a portion of the outer peripheral surface of the conductive substrate.
The electrode for electrolysis according to any one of claims 1 to 3.
The first intermediate layer further includes a portion covering at least a portion of the second main surface of the conductive substrate.
The electrode for electrolysis according to claim 4.
The second intermediate layer includes a striped pattern portion.
The electrode for electrolysis according to any one of claims 1 to 5.
The second intermediate layer includes a grid pattern part.
The electrode for electrolysis according to any one of claims 1 to 6.
The second intermediate layer includes a pattern portion having a plurality of porous portions arranged in a two-dimensional array.
The electrode for electrolysis according to any one of claims 1 to 7.
Further comprising a tantalum oxide layer provided on the catalyst layer,
In the electrolysis electrode, a part of the catalyst layer is exposed,
The electrode for electrolysis according to any one of claims 1 to 8.
The catalyst layer is a porous layer including a plurality of composite particles each containing platinum and iridium oxide and a plurality of pores,
further comprising a tantalum oxide portion provided in at least one of the plurality of pores and in contact with the catalyst layer;
The electrode for electrolysis according to claim 9.
The catalyst layer has a plurality of recesses recessed from the main surface opposite to the conductive substrate side,
The tantalum oxide layer includes a first portion provided on the main surface of the catalyst layer, and a second portion provided on the inner surface of at least one of the plurality of recesses in the catalyst layer. ,including,
The electrode for electrolysis according to claim 9 or 10.
In the catalyst layer, the part of the catalyst layer is exposed by the plurality of recesses,
The electrode for electrolysis according to claim 11.
the first main surface of the conductive substrate is a rough surface;
The electrode for electrolysis according to any one of claims 1 to 12.