JP2020139225A - Electrode for electrolysis and method for producing electrode for electrolysis - Google Patents

Abstract

To provide an electrode for electrolysis and a method for producing the electrode for electrolysis which are excellent in durability and efficiency of electrolytic treatment.SOLUTION: An electrode A1 for electrolysis comprises a conductive substrate 1 containing at least titanium, a plurality of recesses 2, and a plurality of composite layers 3. The plurality of recesses 2 are recessed in the thickness direction of the conductive substrate 1 on a first surface 1a of the conductive substrate 1. The plurality of composite layers 3 are respectively formed inside the plurality of recesses 2. The plurality of composite layers 3 each have at least one catalyst layer 31 containing iridium oxide and platinum and at least one tantalum oxide layer 32 containing tantalum oxide. The catalyst layer 31 and the tantalum oxide layer 32 are laminated along the thickness direction.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an electrode for electrolysis and a method for manufacturing the electrode for electrolysis.

Patent Document 1 discloses an electrode for generating ozone. The ozone generating electrode of Patent Document 1 is composed of a substrate, an intermediate layer formed on the surface of the substrate, and a surface layer formed on the surface of the intermediate layer. The mesosphere contains platinum, iridium oxide, and the like, and has conductivity. The surface layer contains a dielectric such as tantalum oxide. Then, in the surface layer, holes extending continuously from the surface of the surface layer to the inside are formed.

Japanese Unexamined Patent Publication No. 2007-46129

In the conventional electrode for electrolysis as in Patent Document 1, tantalum oxide is a dielectric, which has been a factor of lowering the conductivity of the surface layer. Therefore, it becomes difficult to form a conductive path between the surface layer and the substrate (conductive substrate), and the efficiency of electrolysis treatment (electrolysis efficiency) tends to decrease.

Further, in the electrode for electrolysis using iridium oxide, the function as an electrode may be deteriorated due to the aggregation of iridiums, which has a problem in durability.

Therefore, an object of the present disclosure is to provide an electrolysis electrode and a method for producing an electrolysis electrode, which are excellent in durability and efficiency of electrolysis treatment, respectively.

The electrode for electrolysis according to one aspect of the present disclosure includes a conductive substrate containing at least titanium, a plurality of recesses, and a plurality of composite layers. The plurality of recesses are recessed in the thickness direction of the conductive substrate on at least one surface of the conductive substrate. The plurality of composite layers are each formed inside the plurality of recesses. The plurality of composite layers each have at least one catalyst layer containing iridium oxide and platinum, and at least one tantalum oxide layer containing tantalum oxide. The catalyst layer and the tantalum oxide layer are laminated along the thickness direction.

The method for manufacturing an electrode for electrolysis according to one aspect of the present disclosure includes a recess forming step and a filling step. In the recess forming step, a plurality of recesses recessed in the thickness direction of the conductive substrate are formed on at least one surface of the conductive substrate containing titanium. In the filling step, after the recess forming step, either one of a first solution containing iridium oxide and platinum and a second solution containing tantalum oxide is applied to the at least one surface, and the conductive substrate is fired. To do. After that, in the filling step, either one of the first solution and the second solution is applied to the at least one surface, and the conductive substrate is fired. In the method for manufacturing an electrode for electrolysis, the filling step is performed at least once.

As described above, the present disclosure has the effects of being excellent in durability and efficiency of electrolysis treatment, respectively.

FIG. 1 is a cross-sectional view showing an electrode for electrolysis in the embodiment. FIG. 2 is a perspective view showing the same electrode for electrolysis. FIG. 3 is a flowchart showing a method for manufacturing the electrode for electrolysis as described above. FIG. 4 is a plan view showing a cross section of the composite layer of the electrode for electrolysis described above. FIG. 5 is a plan view showing a cross section of the tantalum oxide layer of the above-mentioned electrode for electrolysis. FIG. 6 is a cross-sectional view showing a modified example of the electrolysis electrode of the above.

The following embodiments generally relate to an electrode for electrolysis and a method for manufacturing the electrode for electrolysis. More specifically, the present invention relates to an electrode for electrolysis in which a composite layer is formed on a conductive substrate, and a method for manufacturing the electrode for electrolysis. Each figure described in the following embodiment is a schematic view, and the ratio of the size and the thickness of each component does not necessarily reflect the actual dimensional ratio. The configuration described in the following embodiments is only an example of the present disclosure. The present disclosure is not limited to the following embodiments, and various changes can be made depending on the design and the like as long as the effects of the present disclosure can be achieved.

Hereinafter, the electrode A1 for electrolysis of the present embodiment will be described with reference to FIGS. 1 to 5. The electrode A1 for electrolysis is used for electrolyzing a liquid, and for example, hypochlorous acid (or chlorine) is produced by electrolyzing an electrolyte solution containing water and a salt. Hypochlorous acid is used for sterilizing or deodorizing spaces. The electrolyte solution that the electrode for electrolysis targets for electrolysis is not limited to a specific electrolyte solution.

As shown in FIGS. 1 and 2, the electrolytic electrode A1 includes a conductive substrate 1, a plurality of recesses 2 recessed in at least the first surface 1a of the conductive substrate 1 in the thickness direction of the conductive substrate 1, and a plurality of recesses 2. A plurality of composite layers 3 formed inside the concave portions 2 of the above are provided. The plurality of composite layers 3 each have at least one catalyst layer 31 containing iridium oxide and platinum, and at least one tantalum oxide layer 32 containing tantalum oxide. The catalyst layer 31 and the tantalum oxide layer 32 are laminated in the thickness direction, respectively. The electrode A1 for electrolysis electrolyzes the electrolyte solution by the electrode reaction between the electrolyte solution and the catalyst layer 31 to generate hypochlorous acid.

The electrode A1 for electrolysis is formed in a plate shape. The electrode A1 for electrolysis has a length along the X axis, a width along the Y axis, and a thickness along the Z axis in a three-dimensional space defined by the X axis, the Y axis, and the Z axis that are orthogonal to each other. It is formed in the shape of a rectangular plate. The size of the electrolysis electrode A1 is, for example, the length dimension (dimension along the X axis) 60 mm of the electrolytic electrode A1 having a rectangular plate shape, the width dimension (dimension along the Y axis) 25 mm of the electrolysis electrode A1, and electrolysis. The thickness dimension (dimension along the Z axis) of the electrode A1 for use is 500 μm. However, each dimension of the electrode A1 for electrolysis is not limited to a specific value, and may be other than the above values. Further, the plan view shape of the electrolysis electrode A1 viewed from the thickness direction may be a triangular shape, a polygonal shape of pentagon or more, a circular shape, or the like, and the plan view shape of the electrolysis electrode A1 has a specific shape. Not limited. The plan view shape of the electrolytic electrode A1 is substantially the same as the plan view shape of the conductive substrate 1.

The conductive substrate 1 may be formed of pure titanium, a titanium alloy, or a substrate obtained by adding impurities to pure titanium. That is, the conductive substrate 1 is a plate-shaped substrate containing at least titanium (Ti). The outer surface of the rectangular plate-shaped conductive substrate 1 is formed of six surfaces, and one of the six surfaces defined by the X-axis and the Y-axis is defined as the first surface 1a.

FIG. 3 is a flowchart showing a method of manufacturing the electrode A1 for electrolysis. In the method for manufacturing the electrode A1 for electrolysis, first, the conductive substrate 1 is prepared, and then the recess forming step S1, the filling step S2, and the determination step S3 are performed.

In the recess forming step S1, a plurality of recesses 2 are formed on the first surface 1a of the conductive substrate 1. In the recess forming step S1, it is preferable that a plurality of recesses 2 are formed by laser processing that irradiates the first surface 1a of the conductive substrate 1 with a laser. The plurality of recesses 2 are recessed in the thickness direction of the conductive substrate 1, and are formed in columns having the thickness direction of the conductive substrate 1 as the axial direction. The plurality of recesses 2 of the present embodiment are each formed in a columnar shape. Further, the plurality of recesses 2 may be formed in a prismatic shape or an elliptical columnar shape, respectively. Further, in the recess forming step S1, a plurality of recesses 2 may be formed by performing an etching process such as dry etching on the first surface 1a of the conductive substrate 1. By forming each of the plurality of recesses 2 in a columnar shape, it becomes difficult for the composite layer 3 to peel off or fall off due to thermal expansion of the composite layer 3, and the durability is improved.

The size of the recess 2 along the first surface 1a is preferably 100 nm or more and 50 μm or less. The size of the recess 2 along the first surface 1a can be reduced to 1 μm by laser processing. Further, the size of the recess 2 along the first surface 1a can be reduced to 1 μm or less by laser processing or etching processing in which the first surface 1a is oxidized to adjust the absorption energy of the laser. The thickness direction of the recess 2 is preferably 0.1 μm or more and 100 μm or less. The thickness direction of the recess 2 can be reduced to 1 μm by laser processing. Further, the dimension of the recess 2 in the thickness direction can be reduced to 1 μm or less by laser processing or etching processing in which the first surface 1a is oxidized to adjust the absorption energy of the laser. Further, the occupancy rate of each opening of the plurality of recesses 2 on the first surface 1a is preferably 50% or more and less than 100%. Specifically, the recess 2 of the present embodiment is formed in a columnar shape, and the diameter of the opening of the recess 2 is within the range of 100 nm or more and 50 μm or less. Further, the dimension from the opening of the recess 2 to the bottom surface is within the range of 0.1 μm or more and 100 μm or less. Further, the occupancy rate of each of the circular openings of the plurality of recesses 2 on the first surface 1a is within the range of 50% or more and less than 100%.

The recess 2 may have a groove shape.

In the filling step S2, the composite layer 3 is formed inside each of the plurality of recesses 2. The composite layer 3 has a plurality of catalyst layers 31 and a plurality of tantalum oxide layers 32. Each of the plurality of catalyst layers 31 and the plurality of tantalum oxide layers 32 are alternately laminated along the thickness direction of the conductive substrate 1. In the composite layer 3 of the present embodiment, the catalyst layer 31 is laminated on the bottom surface of the recess 2, and the catalyst layer 31, the tantalum oxide layer 32, ..., The catalyst layer 31, the tantalum oxide layer are directed from the bottom surface of the recess 2 toward the opening. The catalyst layer 31 and the tantalum oxide layer 32 are alternately laminated so as to be 32. That is, in the composite layer 3, the first end portion in the thickness direction in contact with the bottom surface of the recess 2 is the catalyst layer 31, and the second end portion in the thickness direction located on the opening side of the recess 2 is the tantalum oxide layer 32. In other words, in each of the plurality of recesses 2, one of the plurality of catalyst layers 31 is in contact with the bottom surface of the recess 2. Further, in each of the plurality of recesses 2, one of the plurality of tantalum oxide layers 32 is located on the opening side of the recess 2 with respect to the plurality of catalyst layers 31.

Further, the plurality of catalyst layers 31 are formed in a disk shape inside the recess 2, and the side surface of the catalyst layer 31 is in contact with the inner surface of the recess 2. Further, the plurality of tantalum oxide layers 32 are formed in a disk shape inside the recess 2, and the side surface of the tantalum oxide layer 32 is in contact with the inner surface of the recess 2. That is, the side surface of the catalyst layer 31 and the side surface of the tantalum oxide layer 32 are in contact with the conductive substrate 1 by being in contact with the inner side surface of the recess 2.

The filling step S2 includes a first coating step S21, a first firing step S22, a second coating step S23, and a second firing step S24 in order to alternately laminate the catalyst layer 31 and the tantalum oxide layer 32.

In the first coating step S21, the first solution containing iridium oxide and platinum is coated on the first surface 1a of the conductive substrate 1. The first solution is, for example, a mixed solution of platinum (Pt), iridium (Ir), ethylene glycol monoethyl ether, hydrochloric acid, and ethanol (first precursor solution). In the first coating step S21, it is preferable to mask other than the opening of the recess 2 on the first surface 1a.

In the first firing step S22, the conductive substrate 1 coated with the first solution is fired at a firing temperature of 220 ° C. for 10 minutes. As a result, the catalyst layer 31 having platinum and iridium oxide is laminated on the first surface 1a of the conductive substrate 1. The dimension of the catalyst layer 31 in the thickness direction is, for example, about 50 nm.

In the second coating step S23, the second solution containing tantalum oxide is coated on the surface of the catalyst layer 31 generated in the first firing step S22. The second solution is, for example, a mixed solution of tantalum (Ta), ethylene glycol monoethyl ether, hydrochloric acid, and ethanol (second precursor solution). In the second coating step S23, it is preferable to mask the region other than the opening of the recess 2 in advance on the first surface 1a.

In the second firing step S24, the conductive substrate 1 coated with the second solution is fired at a firing temperature of 220 ° C. for 10 minutes. As a result, the tantalum oxide layer 32 having tantalum oxide is laminated on the surface of the catalyst layer 31. The thickness direction of the tantalum oxide layer 32 is, for example, about 100 nm. The thickness direction of the tantalum oxide layer 32 is preferably about 2 to 3 times the thickness direction of the catalyst layer 31.

As described above, in the filling step S2, the catalyst layer 31 is filled in the plurality of recesses 2, and then the tantalum oxide layer 32 is filled. As a result, in the one filling step S2, one catalyst layer 31 and one tantalum oxide layer 32 can be laminated in the thickness direction in each of the plurality of recesses 2. That is, in one filling step S2, a set of catalyst layer 31 and tantalum oxide layer 32 laminated in the thickness direction can be formed.

The determination step S3 compares the number of fillings (the number of executions of the filling step S2) by the filling step S2 described above with a predetermined threshold value. If the number of fillings is less than the threshold value, the filling step S2 is repeated. If the number of fillings is equal to or greater than the threshold value, this process ends. The threshold value may be an integer of 1 or more, but in the present embodiment, the threshold value is preferably an integer N of 2 or more. That is, in the present embodiment, the filling step S2 is repeated N times. When the number of executions of the filling step S2 reaches N, this process ends. As a result, the N catalyst layers 31 and the N tantalum oxide layers 32 are alternately laminated in the recess 2, and the composite layer 3 is formed in the recess 2.

The method for manufacturing the electrode A1 for electrolysis is a heat treatment step in which the conductive substrate 1 is heat-treated at a heating temperature of 560 ° C. for 10 to 15 minutes after the recess forming step S1, the filling step S2, and the determination step S3. It is preferable to do so.

When the diameter of the recess 2 is 10 μm or less, it is preferable that the catalyst layer 31 and the tantalum oxide layer 32 are laminated inside the recess 2 by a spray method in the first coating step S21 and the second coating step S23.

By the recess forming step S1, the filling step S2, and the determination step S3 described above, the conductive substrate 1, the plurality of recesses 2 recessed in the thickness direction on the first surface 1a of the conductive substrate 1, and the inside of the plurality of recesses 2. An electrolytic electrode A1 including a plurality of composite layers 3 formed in each of the above is manufactured. The plurality of composite layers 3 each have at least one catalyst layer 31 containing iridium oxide and platinum, and at least one tantalum oxide layer 32 containing tantalum oxide. The catalyst layer 31 and the tantalum oxide layer 32 are laminated in the thickness direction, respectively. The electrode A1 for electrolysis electrolyzes the electrolyte solution by the electrode reaction between the electrolyte solution and the catalyst layer 31 to generate hypochlorous acid.

However, in the conventional electrode for electrolysis using iridium oxide, the function as an electrode may be deteriorated due to the aggregation of iridium with each other with the lapse of use time. Specifically, chlorine is produced from a single iridium atom. Oxygen is produced from two iridium atoms. Therefore, when iridiums aggregate with each other, the electrode reaction that contributes to the production of oxygen becomes more dominant than the electrode reaction that contributes to the production of hypochlorous acid. As a result, the efficiency of the electrolysis treatment was reduced.

On the other hand, in the electrode A1 for electrolysis, the composite layer 3 is formed in each of the plurality of recesses 2. That is, the plurality of composite layers 3 are separated from each other by the plurality of recesses 2. Therefore, the amount of iridium oxide contained in one composite layer 3 is limited by the size of the recess 2, and the aggregation of iridium oxide with the lapse of use time can be suppressed. As a result, in the electrode A1 for electrolysis, the electrode reaction that contributes to the production of hypochlorous acid becomes dominant over the electrode reaction that contributes to the production of oxygen even after the lapse of use, and the efficiency of the electrolysis treatment becomes dominant. Can be suppressed from decreasing.

Further, each side surface of the plurality of catalyst layers 31 is in contact with the conductive substrate 1. Therefore, most of the iridium oxide contained in each of the plurality of catalyst layers 31 can contribute to the generation of hypochlorous acid, and the efficiency of the electrolytic treatment is improved.

Further, when the side surface of the catalyst layer 31 and the side surface of the tantalum oxide layer 32 are in contact with the inner side surface of the recess 2, the adhesion of the catalyst layer 31 and the tantalum oxide layer 32 to the recess 2 is improved. As a result, the catalyst layer 31 and the tantalum oxide layer 32 are less likely to peel off or fall off, and the durability is improved.

Therefore, the electrode A1 for electrolysis is an electrode having excellent durability and efficiency of electrolysis treatment, respectively.

Further, in the composite layer 3, N catalyst layers 31 and N tantalum oxide layers 32 are alternately laminated. That is, the catalyst layer of the composite layer 3 is divided into N catalyst layers 31, and the iridium oxide contained in the composite layer 3 is dispersed in each of the N catalyst layers 31. Therefore, the aggregation of iridium oxide with the lapse of use time is further suppressed.

In the above-mentioned electrolytic electrode A1, each of the N catalyst layers 31 and the N tantalum oxide layers 32 are alternately laminated inside the recess 2. A catalyst layer 31 is formed on the bottom surface of the recess 2, and the bottom surface of the recess 2 is in contact with the catalyst layer 31. Therefore, the catalyst layer 31 in contact with the bottom surface of the recess 2 can prevent the electrolyte solution from coming into contact with the first surface 1a of the conductive substrate 1. As a result, corrosion of the conductive substrate 1 can be suppressed.

Further, in each of the plurality of recesses 2, one of the plurality of tantalum oxide layers 32 is located on the opening side of each recess 2 with respect to the plurality of catalyst layers 31. That is, the tantalum oxide layer 32 closes the opening of the recess 2. Therefore, it is possible to prevent the iridium oxide of the catalyst layer 31 from being eluted from the composite layer 3 into the electrolyte solution and transferred to another composite layer 3. As a result, the aggregation of iridium oxide with the passage of use time is further suppressed.

Further, by suppressing the diameter of the opening of the recess 2 to 50 μm or less, the amount of iridium oxide contained in one composite layer 3 can be limited to the extent that aggregation of iridium oxide does not occur. Further, by suppressing the dimension of the recess 2 in the thickness direction to 100 μm or less, the amount of iridium oxide contained in one composite layer 3 can be limited to the extent that iridium oxide does not aggregate. Further, by setting the occupancy rate of each opening of the plurality of recesses 2 on the first surface 1a to 50% or more and less than 100%, aggregation of iridium oxide with the lapse of use time is suppressed and electrolysis is performed. The processing efficiency can be increased.

FIG. 4 shows a cross section (a cross section cut along a ZX plane) along the thickness direction of the recess 2, and in the recess 2, five catalyst layers 31 and five tantalum oxide layers 32 are alternately arranged. It is laminated. Then, it is preferable that the tantalum oxide layer 32 is formed with cracks 4 having a width dimension of 0.05 μm or more and 5 μm or less. The width dimension of the crack 4 is the width dimension of the gap of the crack 4. Further, in the cross section of the tantalum oxide layer 32, the occupancy rate of the crack 4 in the cross section is preferably 5% or more and 50% or less. The cross section may be any of a cross section cut in the XY plane, a cross section cut in the ZZ plane, and a cross section cut in the ZZ plane.

Specifically, the size and density of the cracks 4 can be adjusted by controlling the concentration of the second solution containing tantalum oxide applied in the second coating step S23 and the firing temperature in the second firing step S24.

FIG. 5 is a cross section G1 obtained by cutting the tantalum oxide layer 32 in the XY plane, and cracks 4 are formed in the tantalum oxide layer 32. In this cross section G1, the crack 4 extends in a mesh pattern and divides the tantalum oxide layer 32 into a plurality of small regions. The electrolyte solution penetrates into the crack 4 and becomes a flow path for the electrolyte solution. Therefore, the electrolyte solution easily permeates into the composite layer 3, and the electrode reaction between the electrolyte solution and the catalyst layer 31 tends to occur. Then, by setting the width dimension of the crack 4 in the cross section G1 to 0.01 μm or more, a flow path of the electrolyte solution can be formed in the tantalum oxide layer 32. Further, by setting the width dimension of the crack 4 in the cross section G1 to 5 μm or less, the tantalum oxide layer 32 is less likely to peel off or fall off, and the durability is improved. Further, by setting the occupancy rate of the crack 4 in the cross section G1 to 5% or more, a flow path of the electrolyte solution can be formed in the tantalum oxide layer 32. Further, by setting the occupancy rate of the crack 4 in the cross section G1 to 50% or less, the tantalum oxide layer 32 is less likely to peel off or fall off, and the durability is improved.

Further, it is preferable that the catalyst layer 31 is formed with cracks having a width dimension of 0.005 μm or more and 0.05 μm or less. The cracks in the catalyst layer 31 extend in a mesh pattern and divide the catalyst layer 31 into a plurality of small regions. Then, the electrolyte solution penetrates into the cracks of the catalyst layer 31 and becomes a flow path of the electrolyte solution. Therefore, the electrode reaction between the electrolyte solution and the catalyst layer 31 is likely to occur not only on the surface of the catalyst layer 31 but also in the cracks of the catalyst layer 31. Then, by setting the width dimension of the crack 4 to 0.005 μm or more, a flow path of the electrolyte solution can be formed in the catalyst layer 31. Further, by setting the width dimension of the crack to 0.05 μm or less, the catalyst layer 31 is less likely to peel off or fall off, and the durability is improved.

Specifically, by controlling the concentration of the first solution containing iridium oxide and platinum coated in the first coating step S21 and the firing temperature in the first firing step S22, the size and density of cracks in the catalyst layer 31 Etc. can be adjusted.

Further, in the composite layer 3, the tantalum oxide layer 32 may be formed on the bottom surface of the recess 2, and the bottom surface of the recess 2 may be in contact with the tantalum oxide layer 32. Further, the catalyst layer 31 may close the opening of the recess 2. Further, in the composite layer 3, the number of the catalyst layers 31 and the number of the tantalum oxide layers 32 may be the same or different.

(Modification example)
FIG. 6 shows an electrolytic electrode A2 as a modified example. The outer surface of the rectangular plate-shaped conductive substrate 1 is formed of six surfaces, and of the six surfaces, two surfaces defined by the X-axis and the Y-axis are the first surface 1a and the second surface 1b. And. The first surface 1a and the second surface 1b face each other in the thickness direction.

The electrolysis electrode A2 has a plurality of recesses 2 not only on the first surface 1a but also on the second surface 1b, and a composite layer 3 is formed in each of the plurality of recesses 2 on the second surface 1b. That is, the electrolytic electrode A2 has a composite layer 3 on both sides in the thickness direction. Therefore, since the electrolysis electrode A2 causes an electrode reaction on the two surfaces of the first surface 1a and the second surface 1b, the efficiency of the electrolysis treatment can be made higher than that of the electrolysis electrode A1.

As described above, the electrolysis electrodes (A1, A2) of the first aspect according to the embodiment include a conductive substrate (1) containing at least titanium, a plurality of recesses (2), and a plurality of composite layers (3). ) And. The plurality of recesses (2) are recessed in the thickness direction of the conductive substrate (1) on at least one surface (1a, 1b) of the conductive substrate (1). The plurality of composite layers (3) are each formed inside the plurality of recesses (2). The plurality of composite layers (3) each have at least one catalyst layer (31) containing iridium oxide and platinum, and at least one tantalum oxide layer (32) containing tantalum oxide. The catalyst layer (31) and the tantalum oxide layer (32) are laminated along the thickness direction, respectively.

The above-mentioned electrodes for electrolysis (A1 and A2) are excellent in durability and efficiency of electrolysis treatment, respectively.

In the electrode for electrolysis (A1, A2) of the second aspect according to the embodiment, in the first aspect, it is preferable that the plurality of recesses (2) are formed in a columnar shape along the thickness direction.

In the above-mentioned electrolytic electrodes (A1 and A2), the composite layer (3) is less likely to be peeled off or dropped due to thermal expansion of the composite layer (3), and the durability is improved.

In the first or second aspect, the electrolysis electrode (A1, A2) of the third aspect according to the embodiment preferably includes a plurality of catalyst layers (31) and a plurality of tantalum oxide layers (32). .. Each of the plurality of catalyst layers (31) and the plurality of tantalum oxide layers (32) are formed alternately along the thickness direction.

In the above-mentioned electrodes for electrolysis (A1, A2), aggregation of iridium oxide with the lapse of use time is suppressed.

In the electrode for electrolysis (A1, A2) of the fourth aspect according to the embodiment, in the third aspect, in each of the plurality of recesses (2), one catalyst layer (31) out of the plurality of catalyst layers (31) is used. ) Is preferably in contact with the bottom surface of each recess (2).

The above-mentioned electrolytic electrodes (A1 and A2) can suppress corrosion of the conductive substrate (1).

In the electrolysis electrode (A1, A2) of the fifth aspect according to the embodiment, in the third or fourth aspect, in each of the plurality of recesses (2), one of the plurality of tantalum oxide layers (32). It is preferable that the tantalum oxide layer (32) is located closer to the opening side of each recess (2) than the plurality of catalyst layers (31).

In the above-mentioned electrodes for electrolysis (A1, A2), aggregation of iridium oxide with the lapse of use time is suppressed.

In the electrode for electrolysis (A1, A2) of the sixth aspect according to the embodiment, in any one of the first to fifth aspects, on at least one surface (1a, 1b) of the plurality of recesses (2). Each dimension along the line is preferably 100 nm or more and 50 μm or less. Each dimension of the plurality of recesses (2) in the thickness direction is preferably 0.1 μm or more and 100 μm or less. The occupancy rate of each opening of the plurality of recesses (2) on at least one surface (1a, 1b) is preferably 50% or more and less than 100%.

The above-mentioned electrodes for electrolysis (A1, A2) can suppress the aggregation of iridium oxide with the lapse of use time and increase the efficiency of the electrolysis treatment.

In the electrolytic electrodes (A1, A2) of the seventh aspect according to the embodiment, in any one of the first to sixth aspects, the tantalum oxide layer (32) has a width dimension of 0.05 μm or more. Moreover, it is preferable that cracks (4) of 5 μm or less are formed. In the cross section (G1) of the tantalum oxide layer (32), the occupancy rate of the crack (4) in the cross section (G1) is 5% or more and 50% or less.

In the above-mentioned electrodes for electrolysis (A1, A2), a flow path of the electrolyte solution is formed in the tantalum oxide layer (32) so that the electrolyte solution easily permeates into the composite layer (3) and an electrode reaction is likely to occur. Become. In addition, the tantalum oxide layer (32) is less likely to peel off or fall off, and the durability is improved.

In the electrode for electrolysis (A1, A2) of the eighth aspect according to the embodiment, in any one of the first to seventh aspects, the catalyst layer (31) has a width dimension of 0.005 μm or more and a width dimension of 0.005 μm or more. It is preferable that cracks of 0.05 μm or less are formed.

In the above-mentioned electrolytic electrodes (A1 and A2), an electrode reaction is likely to occur not only on the surface of the catalyst layer (31) but also in the cracks of the catalyst layer (31). In addition, the catalyst layer (31) is less likely to peel off or fall off, and the durability is improved.

In the electrode for electrolysis (A2) of the ninth aspect according to the embodiment, in any one of the first to eighth aspects, at least one surface of the conductive substrate (1) facing the thickness direction 2 It is preferably one surface (1a, 1b).

The above-mentioned electrode for electrolysis (A2) can increase the efficiency of electrolysis treatment.

The method for manufacturing the electrolytic electrodes (A1, A2) according to the tenth aspect according to the embodiment includes a recess forming step (S1) and a filling step (S2). The recess forming step (S1) forms a plurality of recesses (2) recessed in the thickness direction of the conductive substrate (1) on at least one surface (1a, 1b) of the conductive substrate (1) containing titanium. .. In the filling step (S2), after the recess forming step (S1), either one of the first solution containing iridium oxide and platinum and the second solution containing tantalum oxide is formed into at least one surface (1a, 1b). , The conductive substrate (1) is fired. Then, in the filling step (S2), either one of the first solution and the second solution is applied to at least one surface (1a, 1b), and the conductive substrate (1) is fired. Then, in the method for manufacturing the electrodes for electrolysis (A1, A2), the filling step (S2) is performed at least once.

The above-mentioned method for producing electrolytic electrodes (A1 and A2) can produce electrolytic electrodes (A1 and A2) having excellent durability and efficiency of electrolysis treatment, respectively.

Further, in the electrode for electrolysis (A1, A2) of the eleventh aspect according to the embodiment, in any one of the first to sixth and eighth to ninth aspects, the tantalum oxide layer (32) is formed. , Cracks (4) are preferably formed.

Further, in the electrode for electrolysis (A1, A2) of the twelfth aspect according to the embodiment, in any one of the first to seventh, ninth, and eleventh aspects, the catalyst layer (31) is It is preferable that cracks are formed.

A1, A2 Electrode for electrolysis 1 Conductive substrate 1a 1st surface of conductive substrate 1b 2nd surface of conductive substrate 2 Recess 3 Composite layer 31 Catalyst layer 32 Tantal oxide layer 4 Crack G1 Cross section S1 Recess formation process S2 Filling process

Claims (10)

With a conductive substrate containing at least titanium
A plurality of recesses recessed in the thickness direction of the conductive substrate on at least one surface of the conductive substrate,
A plurality of composite layers, each formed inside the plurality of recesses, are provided.
The plurality of composite layers each have at least one catalyst layer containing iridium oxide and platinum, and at least one tantalum oxide layer containing tantalum oxide.
An electrode for electrolysis in which the catalyst layer and the tantalum oxide layer are laminated along the thickness direction. The electrode for electrolysis according to claim 1, wherein the plurality of recesses are formed in a columnar shape along the thickness direction. The catalyst layer and the tantalum oxide layer are provided.
The electrode for electrolysis according to claim 1 or 2, wherein each of the plurality of catalyst layers and the plurality of tantalum oxide layers are alternately formed along the thickness direction. The electrode for electrolysis according to claim 3, wherein in each of the plurality of recesses, one of the plurality of catalyst layers is in contact with the bottom surface of each recess. The electrode for electrolysis according to claim 3 or 4, wherein in each of the plurality of recesses, one of the plurality of tantalum oxide layers is located on the opening side of each recess with respect to the plurality of catalyst layers. Each dimension of the plurality of recesses along the at least one surface is 100 nm or more and 50 μm or less.
Each dimension of the plurality of recesses in the thickness direction is 0.1 μm or more and 100 μm or less.
The electrode for electrolysis according to any one of claims 1 to 5, wherein the occupancy rate of each opening of the plurality of recesses on the at least one surface is 50% or more and less than 100%. Cracks having a width dimension of 0.005 μm or more and 5 μm or less are formed in the tantalum oxide layer.
The electrode for electrolysis according to any one of claims 1 to 6, wherein in the cross section of the tantalum oxide layer, the occupancy rate of the crack in the cross section is 5% or more and 50% or less. The electrode for electrolysis according to any one of claims 1 to 7, wherein cracks having a width dimension of 0.005 μm or more and 0.05 μm or less are formed in the catalyst layer. The electrode for electrolysis according to any one of claims 1 to 8, wherein the at least one surface is two surfaces of the conductive substrate facing in the thickness direction. A recess forming step of forming a plurality of recesses recessed in the thickness direction of the conductive substrate on at least one surface of the conductive substrate containing titanium.
After the recess forming step, either one of the first solution containing iridium oxide and platinum and the second solution containing tantalum oxide is applied to the at least one surface, the conductive substrate is fired, and then the first solution is used. The present invention comprises a filling step of applying either one of the first solution and the second solution to the at least one surface and firing the conductive substrate.
A method for manufacturing an electrode for electrolysis, in which the filling step is performed at least once.

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