EP4074864A1 - Electrolysis electrode - Google Patents
Electrolysis electrode Download PDFInfo
- Publication number
- EP4074864A1 EP4074864A1 EP20898042.5A EP20898042A EP4074864A1 EP 4074864 A1 EP4074864 A1 EP 4074864A1 EP 20898042 A EP20898042 A EP 20898042A EP 4074864 A1 EP4074864 A1 EP 4074864A1
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- EP
- European Patent Office
- Prior art keywords
- catalyst layer
- layer
- electrolysis electrode
- conductive substrate
- tantalum oxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 238000005868 electrolysis reaction Methods 0.000 title claims abstract description 104
- 239000003054 catalyst Substances 0.000 claims abstract description 132
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 claims abstract description 73
- 229910001936 tantalum oxide Inorganic materials 0.000 claims abstract description 71
- 239000000758 substrate Substances 0.000 claims abstract description 60
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 58
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 claims abstract description 26
- 229910000457 iridium oxide Inorganic materials 0.000 claims abstract description 26
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000010936 titanium Substances 0.000 claims abstract description 9
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 9
- 229910003446 platinum oxide Inorganic materials 0.000 claims abstract description 8
- 229910052697 platinum Inorganic materials 0.000 claims description 21
- 239000011148 porous material Substances 0.000 claims description 12
- 239000011246 composite particle Substances 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 31
- 239000000243 solution Substances 0.000 description 22
- 238000000034 method Methods 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 19
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 18
- 239000000460 chlorine Substances 0.000 description 18
- 229910052801 chlorine Inorganic materials 0.000 description 18
- 150000003839 salts Chemical class 0.000 description 16
- QWPPOHNGKGFGJK-UHFFFAOYSA-N hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 description 15
- 238000012360 testing method Methods 0.000 description 15
- 238000001035 drying Methods 0.000 description 14
- 238000004519 manufacturing process Methods 0.000 description 14
- 239000002245 particle Substances 0.000 description 13
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 12
- 239000000463 material Substances 0.000 description 12
- 230000008569 process Effects 0.000 description 11
- 229910052741 iridium Inorganic materials 0.000 description 9
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 9
- 239000002904 solvent Substances 0.000 description 8
- 150000003058 platinum compounds Chemical class 0.000 description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 6
- 239000011780 sodium chloride Substances 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 238000007788 roughening Methods 0.000 description 5
- 229910052715 tantalum Inorganic materials 0.000 description 5
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000002131 composite material Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 150000002504 iridium compounds Chemical class 0.000 description 4
- 150000003482 tantalum compounds Chemical class 0.000 description 4
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- 229910001069 Ti alloy Inorganic materials 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 230000003746 surface roughness Effects 0.000 description 3
- 239000008399 tap water Substances 0.000 description 3
- 235000020679 tap water Nutrition 0.000 description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- CLSUSRZJUQMOHH-UHFFFAOYSA-L platinum dichloride Chemical compound Cl[Pt]Cl CLSUSRZJUQMOHH-UHFFFAOYSA-L 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- NGCRLFIYVFOUMZ-UHFFFAOYSA-N 2,3-dichloroquinoxaline-6-carbonyl chloride Chemical compound N1=C(Cl)C(Cl)=NC2=CC(C(=O)Cl)=CC=C21 NGCRLFIYVFOUMZ-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910001252 Pd alloy Inorganic materials 0.000 description 1
- 229910000929 Ru alloy Inorganic materials 0.000 description 1
- 229910001362 Ta alloys Inorganic materials 0.000 description 1
- 229910000756 V alloy Inorganic materials 0.000 description 1
- YJZATOSJMRIRIW-UHFFFAOYSA-N [Ir]=O Chemical group [Ir]=O YJZATOSJMRIRIW-UHFFFAOYSA-N 0.000 description 1
- ABAGVFOSGPMBFK-UHFFFAOYSA-N [Ti].[Ni].[Ru] Chemical compound [Ti].[Ni].[Ru] ABAGVFOSGPMBFK-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- UQZIWOQVLUASCR-UHFFFAOYSA-N alumane;titanium Chemical compound [AlH3].[Ti] UQZIWOQVLUASCR-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- GSNZLGXNWYUHMI-UHFFFAOYSA-N iridium(3+);trinitrate Chemical compound [Ir+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O GSNZLGXNWYUHMI-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- SJLOMQIUPFZJAN-UHFFFAOYSA-N oxorhodium Chemical compound [Rh]=O SJLOMQIUPFZJAN-UHFFFAOYSA-N 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- HWLDNSXPUQTBOD-UHFFFAOYSA-N platinum-iridium alloy Chemical compound [Ir].[Pt] HWLDNSXPUQTBOD-UHFFFAOYSA-N 0.000 description 1
- 229910003450 rhodium oxide Inorganic materials 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- VSSLEOGOUUKTNN-UHFFFAOYSA-N tantalum titanium Chemical compound [Ti].[Ta] VSSLEOGOUUKTNN-UHFFFAOYSA-N 0.000 description 1
- OEIMLTQPLAGXMX-UHFFFAOYSA-I tantalum(v) chloride Chemical compound Cl[Ta](Cl)(Cl)(Cl)Cl OEIMLTQPLAGXMX-UHFFFAOYSA-I 0.000 description 1
- -1 titanium-aluminum-vanadium Chemical compound 0.000 description 1
- DANYXEHCMQHDNX-UHFFFAOYSA-K trichloroiridium Chemical compound Cl[Ir](Cl)Cl DANYXEHCMQHDNX-UHFFFAOYSA-K 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/052—Electrodes comprising one or more electrocatalytic coatings on a substrate
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
- C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
- C25B11/061—Metal or alloy
- C25B11/063—Valve metal, e.g. titanium
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/24—Halogens or compounds thereof
- C25B1/26—Chlorine; Compounds thereof
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
- C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
- C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
- C25B11/031—Porous electrodes
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
- C25B11/081—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the element being a noble metal
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
- C25B11/093—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds at least one noble metal or noble metal oxide and at least one non-noble metal oxide
Definitions
- the present disclosure relates to electrolysis electrodes and specifically relates to an electrolysis electrode including iridium oxide and platinum.
- Patent Literature 1 There is known a technology that produces hypochlorous acid by causing reaction between water and chlorine produced through electrolysis of a diluted sodium chloride solution obtained by adding salt to tap water.
- Patent Literature 1 discloses an electrode for electrolysis that includes: an electrode body made from titanium or titanium alloy; a titanium oxide layer provided on the electrode body; an intermediate oxide layer provided on the titanium oxide layer, the intermediate oxide layer being made of a composite that contains iridium oxide within a range of 3 to 30 mol% and tantalum oxide within a range of 70 to 97 mol% in metal conversion; and a composite body provided on the intermediate oxide layer, the composite body containing rhodium oxide within a range of 2 to 35 mol%, iridium oxide within a range of 30 to 80 mol%, tantalum oxide within a range of 6 to 35 mol%, and platinum within a range of 12 to 62 mol% in metal conversion.
- Electrolysis electrodes are desirably improved in durability.
- Patent Literature 1 JP 2009-52069 A
- An electrolysis electrode includes a conductive substrate, a catalyst layer, and a tantalum oxide layer.
- the conductive substrate includes at least titanium.
- the catalyst layer is provided on the conductive substrate.
- the catalyst layer includes platinum and iridium oxide.
- the tantalum oxide layer is provided on the catalyst layer. In the electrolysis electrode, the catalyst layer is partially exposed.
- FIGS. 1A, 1B , 2 , 3A to 3D , and 4 described in the following embodiment and the like are schematic views, and the ratio of sizes and the ratio of thicknesses of components in the figures do not necessarily reflect actual dimensional ratios.
- An electrolysis electrode 1 according to an embodiment will be described below with reference to FIGS. 1A to 3D .
- the electrolysis electrode 1 is an electrode used to produce chlorine by electrolyzing salt water.
- the salt water is, for example, a sodium chloride solution.
- the electrolysis electrode 1 is used for an application of electrolyzing salt water, and in this case, the electrolysis electrode 1 is used as an anode, of a cathode and the anode to which a direct-current voltage is applied from a power supply, thereby electrolyzing a sodium chloride solution to produce chlorine, and through reaction of the chlorine with water, hypochlorous acid water can be produced.
- the electrolysis electrode 1 includes a conductive substrate 2, a catalyst layer 4, and a tantalum oxide layer 5.
- the catalyst layer 4 is provided on the conductive substrate 2.
- the tantalum oxide layer 5 is provided on the catalyst layer 4.
- the electrolysis electrode 1 further includes an intermediate layer 3 provided between the conductive substrate 2 and the catalyst layer 4.
- the conductive substrate 2 has a first principal surface 21 and a second principal surface 22 located opposite the first principal surface 21.
- the shape of the conductive substrate 2 in plan view (the outer peripheral shape of the conductive substrate 2 when viewed in the thickness direction defined with respect to the conductive substrate 2) is rectangular.
- the thickness of the conductive substrate 2 is, for example, greater than or equal to 100 ⁇ m and less than or equal to 2 mm and is, for example, 500 ⁇ m.
- the size of the conductive substrate 2 in plan view is, for example, 25 mm ⁇ 60 mm.
- the conductive substrate 2 includes at least titanium.
- the conductive substrate 2 is, for example, a titanium substrate.
- the material for the conductive substrate 2 is titanium or an alloy including titanium as a main component (hereinafter referred to as a titanium alloy).
- the titanium alloy is, for example, a titanium-palladium alloy, a titanium-nickel-ruthenium alloy, a titanium-tantalum alloy, a titanium-aluminum alloy, or a titanium-aluminum-vanadium alloy.
- the first principal surface 21 of the conductive substrate 2 is preferably a rough surface to improve adhesiveness to the intermediate layer 3.
- the first principal surface 21 of the conductive substrate 2 is roughened before the intermediate layer 3 is provided.
- an arithmetic mean roughness Ra is, for example, 0.7 ⁇ m
- a maximum height Rz is 7 ⁇ m.
- the arithmetic mean roughness Ra and the maximum height Rz are specified in, for example, JIS B 0601-2001 (ISO 4287-1997).
- the arithmetic mean roughness Ra and the maximum height Rz are values measured from, for example, a Crosssectional Scanning Electron Microscope (SEM) Image.
- the intermediate layer 3 is provided on the conductive substrate 2. More specifically, the intermediate layer 3 is provided on the first principal surface 21 of the conductive substrate 2.
- the electrolysis electrode 1 has an interface between the conductive substrate 2 and the intermediate layer 3.
- the intermediate layer 3 is preferably made of a material having corrosion resistance against salt water and chlorine and having higher corrosion resistance than the conductive substrate 2.
- the material for the intermediate layer 3 is preferably a conductive material having high electrical conductivity.
- the material for the intermediate layer 3 is, for example, transition metal or a mixture including the transition metal and is, for example, platinum; a mixture of tantalum, platinum, and iridium; iridium; iridium oxide; or nickel.
- the material for the intermediate layer 3 is, for example, platinum.
- the thickness of the intermediate layer 3 is, for example, greater than or equal to 0.2 ⁇ m and less than or equal to 5 ⁇ m, and is, for example, 0.6 ⁇ m.
- the catalyst layer 4 is provided on the intermediate layer 3.
- the electrolysis electrode 1 has an interface between the catalyst layer 4 and the intermediate layer 3. That is, the catalyst layer 4 is provided on the intermediate layer 3 on the conductive substrate 2.
- the catalyst layer 4 includes platinum and iridium oxide. As shown in FIG. 1B , 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. 2 , each of the plurality of composite particles 41 includes a platinum particle 411 and iridium oxide particles 412. 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, the iridium oxide is dispersed by the platinum. The iridium oxide functions as a catalyst for producing chlorine. In the catalyst layer 4, the molar ratio of the platinum to the iridium oxide is, for example, but not limited to, 8:5.
- the molar quantity of the iridium oxide is preferably less than or equal to the molar quantity of the platinum.
- the catalyst layer 4 may include iridium in addition to the platinum and the iridium oxide.
- each of the composite particles 41 may include, in addition to the iridium oxide particles 412, at least one iridium particle bonded to the platinum particle 411.
- the platinum particles 411 may be bonded to each other.
- the bonding state in the catalyst layer 4 is not particularly limited.
- the catalyst layer 4 has a plurality of recesses 45 recessed from a principal surface 40 on an opposite side of the catalyst layer 4 from the conductive substrate 2. In the electrolysis electrode 1, the catalyst layer 4 is partially exposed in 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 crack which is linear in plan view in the thickness direction defined with respect to the catalyst layer 4.
- the plurality of cracks (recesses 45) have different shapes. Moreover, each crack may be formed along the thickness direction defined with respect to the catalyst layer 4 or may have a bent on the way in the thickness direction defined with respect to the catalyst layer 4.
- each of the plurality of recesses 45 is, for example, greater than or equal to 0.1 ⁇ m.
- the depth of each of the plurality of recesses 45 may be a depth reaching the intermediate layer 3 or may be a depth not reaching the intermediate layer 3.
- the plurality of recesses 45 do not extend through the intermediate layer 3, and the entirety of the first principal surface 21 of the conductive substrate 2 is covered with the intermediate layer 3.
- the width of each of the plurality of recesses 45 is greater than or equal to 0.1 ⁇ m and less than or equal to 10 ⁇ m and is preferably greater than or equal to 0.3 ⁇ m and less than or equal to 3 ⁇ m.
- each recess 45 in plan view in the thickness direction defined with respect to the conductive substrate 2 is an opening width in a short direction (in a direction orthogonal to the length direction) on the principal surface 40 of the catalyst layer 4.
- 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, within a range of 0.1 ⁇ m to 10 ⁇ m.
- the percentage of S2 to (S1+S2) is, for example, higher than or equal to 5% and lower than or equal to 50%, where S1 is the area of the principal surface 40 of the catalyst layer 4, and S2 is the total area of opening areas of the plurality of recesses 45 in the principal surface 40 of the catalyst layer 4.
- the percentage of S2 to (S1+S2) is preferably higher than or equal to 5% to improve the production efficiency of chlorine.
- the percentage of S2 to (S1+S2) is preferably lower than or equal to 50%, more preferably lower than or equal to 20%, to suppress, for example, peel-off of the catalyst layer 4. That is, the percentage of S2 to (S1+S2) is more preferably higher than or equal to 5% and lower than or equal to 20%.
- the tantalum oxide layer 5 has a function of suppressing elution of the iridium oxide of the catalyst layer 4.
- the tantalum oxide layer 5 has a first portion 51 provided on the principal surface 40 of the catalyst layer 4 and a second portion 52 provided on an inner surface 451 of at least one recess 45 of the plurality of recesses 45 in the catalyst layer 4.
- the tantalum oxide layer 5 preferably has the second portion 52 on the inner surface 451 of each of the plurality of recesses 45 in the catalyst layer 4.
- the molar quantity of tantalum in the tantalum oxide layer 5 and iridium in the iridium oxide is preferably lower than or equal to 60% of the total molar quantity of the molar quantity of the iridium and the molar quantity of the platinum.
- the electrolysis electrode 1 further includes tantalum oxide 43 provided in least one pore 42 of the plurality of pores 42, and the tantalum oxide 43 is in contact with the catalyst layer 4.
- the tantalum oxide 43 is formed, for example, at the time of forming the tantalum oxide layer 5.
- the tantalum oxide 43 is in contact with the composite particles 41 of the catalyst layer 4.
- the conductive substrate 2 is prepared at first, and then, a surface roughening step, an intermediate layer forming step, a catalyst layer forming step, and a tantalum oxide layer forming step are sequentially performed.
- the surface roughening step includes immersing, for example, the conductive substrate 2 in an oxalic acid aqueous solution, thereby roughening the first principal surface 21 of the conductive substrate 2 (see FIG. 3A ).
- the surface roughening step is not an essential step.
- an arithmetic mean roughness Ra is, for example, 0.7 ⁇ m, and a maximum height Rz is 7 ⁇ m.
- the arithmetic mean roughness Ra and the maximum height Rz may be values measured with a surface roughness meter of Zygo Co.
- the intermediate layer forming step includes forming the intermediate layer 3 on the first principal surface 21 of the conductive substrate 2 (see FIG. 3B ).
- the intermediate layer 3 is, for example, a platinum layer.
- the intermediate layer forming step includes applying a solution which will be the intermediate layer 3 and then performing a heating process, and thereafter, baking the solution, thereby forming the intermediate layer 3.
- the solution is a solution obtained by dissolving a platinum compound in a solvent.
- the solvent is, for example, liquid obtained by mixing ethylene glycol monoethyl ether and hydrochloric acid and ethanol.
- the platinum compound is, for example, but not limited to, chloroplatinic acid, and the platinum compound may be, for example, platinum chloride.
- the formation method of the intermediate layer 3 is not limited to the examples described above but may be, for example, a vapor-deposition method, a sputtering method, a CVD method, or a plating method.
- the catalyst layer forming step includes forming the catalyst layer 4 on the intermediate layer 3 (see FIG. 3C ).
- the catalyst layer forming step includes a first step and a second step.
- the first step of the catalyst layer forming step includes performing an application step at least once and a drying step at least once, thereby forming a catalyst material layer which will be the catalyst layer 4 on the intermediate layer 3 on the conductive substrate 2.
- the number of times of performing the application step and the drying step is determined based on, for example, a prescribed thickness of the catalyst layer 4. Regarding the number of times of performing the application step and the drying step, the number of times of performing the application step and the drying step is at least increased as the prescribed thickness of the catalyst layer 4 increases.
- a first specified number of times (e.g., eight times) of application steps and the first specified number of times of drying steps are alternately repeated one by one, thereby forming the catalyst material layer which will be the catalyst layer 4 on the intermediate layer 3 on the conductive substrate 2.
- a solution (hereinafter referred to as a first solution) including the platinum compound which will be the catalyst layer 4 and the iridium compound is directly or indirectly applied onto the intermediate layer 3 on the conductive substrate 2 (the application step is performed), and then, a heating process of drying the first solution by heating under a first condition (the drying step) is performed at least once (e.g., eight times), thereby forming the catalyst material layer which will be the catalyst layer 4.
- the first solution is a solution obtained by dissolving the platinum compound and the iridium compound in a solvent (hereinafter referred to as a first solvent).
- the first solvent is, for example, liquid obtained by mixing ethylene glycol monoethyl ether and hydrochloric acid and ethanol.
- the platinum compound is, for example, but not limited to, chloroplatinic acid, and the platinum compound may be, for example, platinum chloride.
- the chloroplatinic acid is, for example, hydrogen hexachloroplatinate(IV) n-hydrate.
- the iridium compound is, for example, but not limited to, chloroiridic acid, and the iridium compound may be, for example, iridium chloride or iridium nitrate.
- the chloroiridic acid is, for example, hexachloroiridate(IV) n-hydrate.
- the metal concentration (the total concentration of platinum and iridium) of the first solution is, for example, 50 mg/mL. Moreover, the application quantity of the first solution is, for example, 2 ⁇ L/cm 2 .
- the first condition includes a heat process temperature and a heat process time.
- the heat process temperature in the first condition is within a range of 100°C to 400°C, for example, and may be 220°C as an example.
- the heat process time in the first condition is within a range of 5 minutes to 15 minutes, for example, and may be 10 minutes as an example.
- the baking condition includes a baking temperature and a baking time.
- the baking temperature is within a range of 500°C to 700°C, for example, and may be 560°C as an example.
- the baking time is within a range of 5 minutes to 20 minutes, for example, and may be 10 minutes as an example.
- the tantalum oxide layer forming step includes forming the tantalum oxide layer 5 on the catalyst layer 4 (see FIG. 3D ).
- the tantalum oxide layer forming step includes a first step and a second step.
- the first step of the tantalum oxide layer step includes performing an application step at least once and a drying step at least once, thereby forming a material layer which will be the tantalum oxide layer 5 on the catalyst layer 4.
- the number of times of performing the application step and the drying step is determined based on, for example, a prescribed thickness of the tantalum oxide layer 5.
- the number of times of performing the application step and the drying step is at least increased as the prescribed thickness of the tantalum oxide layer 5 increases.
- the application step is performed a second specified number of times (e.g., once) and the drying step is performed the second specified number of times, thereby forming the material layer which will be the tantalum oxide layer 5 on the catalyst layer 4.
- a solution (hereinafter referred to as a second solution) including a tantalum compound which will be the tantalum oxide layer 5 is applied onto the catalyst layer 4 (that is, the application step is performed), and then a heat process of drying the second solution by heating under the second condition (the drying step) is performed at least once (e.g., once), thereby forming the metal layer which will be the tantalum oxide layer 5.
- the second solution is a solution obtained by dissolving the tantalum compound in a solvent (hereinafter referred to as a second solvent).
- the second solvent is, for example, liquid obtained by mixing ethylene glycol monoethyl ether and hydrochloric acid and ethanol.
- the tantalum compound is, for example, but not limited to, tantalum chloride, and the tantalum compound may be, for example, tantalum ethoxide.
- the metal concentration (tantalum concentration) of the second solution is, for example, 50 mg/L.
- the application quantity of the second solution is, for example, 1 ⁇ L/cm 2 .
- the second condition includes a heat process temperature and a heat process time.
- the heat process temperature in the second condition is within a range of 100°C to 400°C and may be 220°C as an example.
- the heat process time in the second condition is within a range of 5 minutes to 15 minutes, for example, and may be 10 minutes as an example.
- the heat process of baking the material layer under a prescribed baking condition is performed, thereby forming the tantalum oxide layer 5 (see FIG. 3D ).
- the baking condition includes a baking temperature and a baking time.
- the baking temperature is within a range of 500°C to 700°C, for example, and may be 560°C as an example.
- the baking time is within a range of 5 minutes to 20 minutes, for example, and may be 10 minutes as an example.
- the tantalum oxide 43 in at least one of the pores 42 in the catalyst layer 4 is formed in the tantalum oxide layer forming step.
- FIG. 5 is a graph of results of a durability test conducted on an electrolysis electrode 1 according to Example of the embodiment, an electrolysis electrode according to Comparative Example 1, and an electrolysis electrode 1r (see FIG. 4 ) according to Comparative Example 2.
- the electrolysis electrode according to Comparative Example 1 is different from the electrolysis electrode 1 according to Example in that Comparative Example 1 does not include the tantalum oxide layer of the electrolysis electrode 1 according to Example.
- the electrolysis electrode 1r according to Comparative Example 2 includes 15 tantalum oxide layers 6 and 15 catalyst layers 7 alternately stacked one by one instead of the catalyst layer 4 and the tantalum oxide layer 5 of the electrolysis electrode 1 according to the embodiment. In FIG. 4 , only three of the tantalum oxide layers 6 and only three of the catalyst layers 7 are shown. In the electrolysis electrode 1r according to Comparative Example 2, the total catalyst amount of the 15 catalyst layers 7 is the same as the catalyst amount of the electrolysis electrode 1 according to Example.
- the catalyst layer 7 includes platinum and iridium oxide. In the electrolysis electrode 1r according to Comparative Example 2, a composite layer including the 15 tantalum oxide layers 6 and the 15 catalyst layers 7 has a plurality of cracks.
- the durability test is accelerated testing.
- the durability test was performed in which two electrolysis electrodes 1 (or two electrolysis electrodes or two electrolysis electrodes 1r) formed under the same condition were adopted as pair of electrodes, and the pair of electrodes were immersed in salt water in an electrolytic bath in a durability test facility.
- polarity reversal was performed each time the pair of electrodes are energized for a predetermined time (3 minutes). In this case, the polarity reversal means that a combination of the anode and the cathode in the pair of electrodes is reversed.
- the polarity reversal means that an electrode of the pair of electrodes which is on a high-potential side is changed such that an electrode used as the anode and an electrode used as the cathode are respectively used as the cathode and the anode.
- the electrolytic bath in the durability test facility has a water inlet and a water outlet for salt water.
- salt water is added so that the electric conductivity of the salt water in the electrolytic bath is 1650 ⁇ 165 ⁇ S/cm.
- the electrolytic bath in the durability test facility is drained while tap water is constantly supplied to the electrolytic bath at a flow rate of 2 L/min.
- the salt water supplied to the electrolytic bath in the durability test facility is a sodium chloride solution obtained by dissolving salt (sodium chloride) in tap water.
- the current value of an energization current in the durability test is 400 mA.
- the electrodes were taken out of the electrolytic bath in the durability test facility at the time of measuring the hypochlorous acid water concentration, and the hypochlorous acid water concentration was measured as described below.
- salt water in an electrolytic bath for measuring a hypochlorous acid water concentration salt water produced by dissolving 4.5 g salt (sodium chloride) in 800 mL pure water was used.
- the current value of an energization current for measuring the hypochlorous acid water concentration is 400 mA.
- the polarity reversal was performed each time the pair of electrodes were energized for a predetermined time (3 minutes), and in this way, the pair of electrodes were energized for a total of 12 minutes.
- electrolysis was performed for 12 minutes under the same condition as the initial aging, and then, some of the electrolysis water was taken out every 3 minutes, and the hypochlorous acid water concentration was measured.
- the free chlorine concentration HACH, Pocket Colorimeter II 58700-00
- the polarity reversal means that a combination of the anode and the cathode in the pair of electrodes is reversed.
- the polarity reversal means that an electrode of the pair of electrodes which is on a high-potential side is changed such that an electrode used as the anode and an electrode used as the cathode are respectively used as the cathode and the anode.
- the abscissa in FIG. 5 represents a durability test time (elapsed time).
- the ordinate in FIG. 5 represents the hypochlorous acid water concentration measured after the energization for a unit time (3 minutes) was performed at the time.
- chlorine produced in the vicinity of the anode contributes to production of hypochlorous acid, and therefore, the hypochlorous acid water concentration is substantially determined based on the amount of the chlorine produced per unit time.
- the hypochlorous acid water concentration is higher and a time until the hypochlorous acid water concentration decreases to or less than a prescribed value (e.g., 5 mg/L) is longer (the durability is improved more) than in the electrolysis electrode according to Comparative Example 1 and the electrolysis electrode 1r according to Comparative Example 2.
- a prescribed value e.g., 5 mg/L
- the durability is determined based on elution caused by consumption of the catalyst layer 4, peel-off of the catalyst layer 4, or the like.
- the tantalum oxide layers 6 and the catalyst layers 7 are alternately stacked, and therefore, a conduction path and a path of gas are narrow, the amount of chlorine produced per unit time is small, and the number of active points not used is large, and therefore, the electrolysis electrode 1r is presumed to have reduced service life.
- chlorine is more easily produced than in the electrolysis electrode 1r according to Comparative Example 2, but the catalyst is more likely to desorb than in the electrolysis electrode 1 according to Example, and therefore, the electrolysis electrode according to Comparative Example 1 is presumed to have shorter service life than the electrolysis electrode 1 according to Example.
- FIG. 5 it can be seen from FIG. 5 that the electrolysis electrode 1 according to Example is capable of producing a larger amount of chlorine and thus has a longer service life than the electrolysis electrode according to Comparative Example 1 and the electrolysis electrode 1r according to Comparative Example 2.
- the electrolysis electrode 1 according to the embodiment includes the tantalum oxide layer 5 provided on the catalyst layer 4 including platinum and iridium oxide, and the catalyst layer 4 is partially exposed, which enables the durability to be improved. This enables the electrolysis electrode 1 according to the embodiment to make the catalyst layer 4 contribute to production of chlorine and to have improved durability compared to the case where the entirety of the principal surface 40 of the catalyst layer 4 is in contact with salt water.
- the electrolysis electrode 1 according to the embodiment includes the tantalum oxide layer 5 and the tantalum oxide 43, which enables platinum iridium to be suppressed from being excessively consumed (eluted) from the catalyst layer 4 during use, thereby suppressing a rapid structural change in the catalyst layer 4, and partial desorption of the catalyst layer 4 and peel-off of the catalyst layer 4 can be suppressed. Moreover, in the electrolysis electrode 1 according to the embodiment, the agglomeration of iridium can be suppressed.
- the electrolysis electrode 1 includes the tantalum oxide 43 which is provided in the plurality of pores 42 in the catalyst layer 4 and which is in contact with the catalyst layer 4, which enables the mechanical intensity of the catalyst layer 4 to be improved and enables excessive consumption of iridium oxide, agglomeration of the iridium oxide, and the like to be suppressed.
- the embodiment is a mere example of various embodiments of the present disclosure. Various modifications may be made to the embodiment depending on design and the like as long as the object of the present disclosure is achieved.
- the shape of the conductive substrate 2 in plan view is not limited to a rectangular shape, but may be, for example, a square shape.
- the catalyst layer 4 is not limited to a porous layer but may be a non-porous layer.
- the plurality of recesses 45 may have the same shape.
- the plurality of recess 45 may be formed by an etching technique, a laser processing technique, or the like. Using these techniques provides the advantages that the degree of freedom of design in terms of the layout and the size of the plurality of recesses 45 is increased and the reproducibility of formation locations of the plurality of recesses 45 is increased.
- the catalyst layer 4 does not have to have the plurality of recesses 45, and in this case, for example, the tantalum oxide layer 5 has at least a plurality of holes (e.g., pin holes or cracks) through which the principal surface 40 of the catalyst layer 4 is partially exposed.
- the tantalum oxide layer 5 has at least a plurality of holes (e.g., pin holes or cracks) through which the principal surface 40 of the catalyst layer 4 is partially exposed.
- the tantalum oxide layer 5 may have a plurality of cracks through which the catalyst layer 4 is partially exposed.
- the thickness of the tantalum oxide layer 5 is greater than or equal to 50 nm, cracks through which the catalyst layer 4 is partially exposed may be formed in the tantalum oxide layer 5 in the second step of the tantalum oxide layer forming step.
- cracks may be formed in the tantalum oxide layer in the second step of the tantalum oxide layer forming step, and in addition, cracks continuous with the cracks in the tantalum oxide layer may be formed in the catalyst layer 4.
- the plurality of holes in the tantalum oxide layer 5 may be formed by an etching technique, a laser processing technique, or the like.
- the electrolysis electrode 1 may include a titanium oxide layer provided between the conductive substrate 2 and the intermediate layer 3.
- the tantalum oxide layer 5 may include tantalum in addition to the tantalum oxide.
- the tantalum oxide layer 5 may be a layer in which tantalum oxide and tantalum are included.
- the electrolysis electrode 1 may further include, on the second principal surface 22 of the conductive substrate 2, a structural component similar to a structural component including the intermediate layer 3, the catalyst layer 4, and the tantalum oxide layer 5 at the side of the first principal surface 21.
- An electrolysis electrode (1) of a first aspect includes a conductive substrate (2), a catalyst layer (4), and a tantalum oxide layer (5).
- the conductive substrate (2) includes at least titanium.
- the catalyst layer (4) is provided on the conductive substrate (2).
- the catalyst layer (4) includes platinum and iridium oxide.
- the tantalum oxide layer (5) is provided on the catalyst layer (4). In the electrolysis electrode (1), the catalyst layer (4) is partially exposed.
- the electrolysis electrode (1) of the first aspect has improved durability.
- the catalyst layer (4) is a porous layer including: a plurality of composite particles (41) each including platinum (a platinum particle 411) and iridium oxide (iridium oxide particles 412); and a plurality of pores (42).
- the electrolysis electrode (1) further includes tantalum oxide (43) provided in at least one pore (42) of the plurality of pores (42), and the tantalum oxide (43) is in contact with the catalyst layer (4).
- the electrolysis electrode (1) according to the second aspect has improved production efficiency of chlorine with improved durability.
- the catalyst layer (4) has a plurality of recesses (45) recessed from a principal surface (40) on an opposite side of the catalyst layer (4) from the conductive substrate (2).
- the tantalum oxide layer (5) has: a first portion (51) provided on the principal surface (40) of the catalyst layer (4); and a second portion (52) provided on an inner surface (451) of at least one recess (45) of the plurality of recesses (45) in the catalyst layer (4).
- the electrolysis electrode (1) according to the third aspect has improved production efficiency of chlorine with improved durability.
- the catalyst layer (4) is partially exposed in the plurality of recesses (45).
- salt water easily enters the catalyst layer (4) in an in-plane direction of the catalyst layer (4) through the inner surface (451) of the at least one recess (45), the inner surface (451) being exposed through the at least one recess (45).
- the catalyst layer (4) readily contributes to production of chlorine, which enables the durability to be improved.
- An electrolysis electrode (1) of a fifth aspect referring to any one of the first to fourth aspects further includes an intermediate layer (3).
- the intermediate layer (3) is provided between the conductive substrate (2) and the catalyst layer (4).
- the intermediate layer (3) includes platinum.
- the conductive substrate (2) has a principal surface (a first principal surface 21) facing the catalyst layer (4), and the principal surface is a rough surface.
- the adhesiveness between the conductive substrate (2) and the intermediate layer (3) is improved, which enables the catalyst layer (4) to be suppressed from peeling off from a side of the conductive substrate (2), thereby improving the durability.
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Abstract
Description
- The present disclosure relates to electrolysis electrodes and specifically relates to an electrolysis electrode including iridium oxide and platinum.
- There is known a technology that produces hypochlorous acid by causing reaction between water and chlorine produced through electrolysis of a diluted sodium chloride solution obtained by adding salt to tap water (Patent Literature 1).
-
Patent Literature 1 discloses an electrode for electrolysis that includes: an electrode body made from titanium or titanium alloy; a titanium oxide layer provided on the electrode body; an intermediate oxide layer provided on the titanium oxide layer, the intermediate oxide layer being made of a composite that contains iridium oxide within a range of 3 to 30 mol% and tantalum oxide within a range of 70 to 97 mol% in metal conversion; and a composite body provided on the intermediate oxide layer, the composite body containing rhodium oxide within a range of 2 to 35 mol%, iridium oxide within a range of 30 to 80 mol%, tantalum oxide within a range of 6 to 35 mol%, and platinum within a range of 12 to 62 mol% in metal conversion. - Electrolysis electrodes are desirably improved in durability.
- Patent Literature 1:
JP 2009-52069 A - It is an object of the present disclosure to provide an electrolysis electrode with improved durability.
- An electrolysis electrode according to an aspect of the present disclosure includes a conductive substrate, a catalyst layer, and a tantalum oxide layer. The conductive substrate includes at least titanium. The catalyst layer is provided on the conductive substrate. The catalyst layer includes platinum and iridium oxide. The tantalum oxide layer is provided on the catalyst layer. In the electrolysis electrode, the catalyst layer is partially exposed.
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FIG. 1A is a sectional view of an electrolysis electrode according to an embodiment; -
FIG. 1B is an illustrative view of a main part of the electrolysis electrode; -
FIG. 2 is an illustrative view of particles included in a catalyst layer of the electrolysis electrode; -
FIGS. 3A to 3D are sectional views illustrating respective steps in a manufacturing method of the electrolysis electrode; -
FIG. 4 is a sectional view of an electrolysis electrode according to Comparative Example 2; and -
FIG. 5 is a graph of results of a durability test conducted on an electrolysis electrode according to Example of the embodiment, an electrolysis electrode according to Comparative Example 1, and an electrolysis electrode according to Comparative Example 2. -
FIGS. 1A, 1B ,2 ,3A to 3D , and4 described in the following embodiment and the like are schematic views, and the ratio of sizes and the ratio of thicknesses of components in the figures do not necessarily reflect actual dimensional ratios. - An
electrolysis electrode 1 according to an embodiment will be described below with reference toFIGS. 1A to 3D . - The
electrolysis electrode 1 is an electrode used to produce chlorine by electrolyzing salt water. In this case, the salt water is, for example, a sodium chloride solution. Suppose theelectrolysis electrode 1 is used for an application of electrolyzing salt water, and in this case, theelectrolysis electrode 1 is used as an anode, of a cathode and the anode to which a direct-current voltage is applied from a power supply, thereby electrolyzing a sodium chloride solution to produce chlorine, and through reaction of the chlorine with water, hypochlorous acid water can be produced. - As illustrated in
FIG. 1A , theelectrolysis electrode 1 includes aconductive substrate 2, acatalyst layer 4, and atantalum oxide layer 5. Thecatalyst layer 4 is provided on theconductive substrate 2. Thetantalum oxide layer 5 is provided on thecatalyst layer 4. Theelectrolysis electrode 1 further includes anintermediate layer 3 provided between theconductive substrate 2 and thecatalyst layer 4. - These components of the
electrolysis electrode 1 will be described in further detail below. - The
conductive substrate 2 has a firstprincipal surface 21 and a secondprincipal surface 22 located opposite the firstprincipal surface 21. The shape of theconductive substrate 2 in plan view (the outer peripheral shape of theconductive substrate 2 when viewed in the thickness direction defined with respect to the conductive substrate 2) is rectangular. The thickness of theconductive substrate 2 is, for example, greater than or equal to 100 µm and less than or equal to 2 mm and is, for example, 500 µm. The size of theconductive substrate 2 in plan view is, for example, 25 mm × 60 mm. - The
conductive substrate 2 includes at least titanium. Theconductive substrate 2 is, for example, a titanium substrate. The material for theconductive substrate 2 is titanium or an alloy including titanium as a main component (hereinafter referred to as a titanium alloy). The titanium alloy is, for example, a titanium-palladium alloy, a titanium-nickel-ruthenium alloy, a titanium-tantalum alloy, a titanium-aluminum alloy, or a titanium-aluminum-vanadium alloy. - The first
principal surface 21 of theconductive substrate 2 is preferably a rough surface to improve adhesiveness to theintermediate layer 3. In theelectrolysis electrode 1 according to the embodiment, the firstprincipal surface 21 of theconductive substrate 2 is roughened before theintermediate layer 3 is provided. Regarding the surface roughness of the firstprincipal surface 21 of theconductive substrate 2, an arithmetic mean roughness Ra is, for example, 0.7 µm, and a maximum height Rz is 7 µm. The arithmetic mean roughness Ra and the maximum height Rz are specified in, for example, JIS B 0601-2001 (ISO 4287-1997). The arithmetic mean roughness Ra and the maximum height Rz are values measured from, for example, a Crosssectional Scanning Electron Microscope (SEM) Image. - The
intermediate layer 3 is provided on theconductive substrate 2. More specifically, theintermediate layer 3 is provided on the firstprincipal surface 21 of theconductive substrate 2. Theelectrolysis electrode 1 has an interface between theconductive substrate 2 and theintermediate layer 3. Theintermediate layer 3 is preferably made of a material having corrosion resistance against salt water and chlorine and having higher corrosion resistance than theconductive substrate 2. Moreover, to increase the electrical conductivity of theelectrolysis electrode 1 as a whole, the material for theintermediate layer 3 is preferably a conductive material having high electrical conductivity. The material for theintermediate layer 3 is, for example, transition metal or a mixture including the transition metal and is, for example, platinum; a mixture of tantalum, platinum, and iridium; iridium; iridium oxide; or nickel. The material for theintermediate layer 3 is, for example, platinum. The thickness of theintermediate layer 3 is, for example, greater than or equal to 0.2 µm and less than or equal to 5 µm, and is, for example, 0.6 µm. - The
catalyst layer 4 is provided on theintermediate layer 3. Theelectrolysis electrode 1 has an interface between thecatalyst layer 4 and theintermediate layer 3. That is, thecatalyst layer 4 is provided on theintermediate layer 3 on theconductive substrate 2. - The
catalyst layer 4 includes platinum and iridium oxide. As shown inFIG. 1B , thecatalyst layer 4 is a porous layer including a plurality ofcomposite particles 41 and a plurality ofpores 42. As shown inFIG. 2 , each of the plurality ofcomposite particles 41 includes aplatinum particle 411 andiridium oxide particles 412. In each of the plurality ofcomposite particles 41, for example, a plurality ofiridium oxide particles 412 are bonded to oneplatinum particle 411. In thecatalyst layer 4, the iridium oxide is dispersed by the platinum. The iridium oxide functions as a catalyst for producing chlorine. In thecatalyst layer 4, the molar ratio of the platinum to the iridium oxide is, for example, but not limited to, 8:5. To suppress iridium from agglomerating over time as theelectrolysis electrode 1 is used, the molar quantity of the iridium oxide is preferably less than or equal to the molar quantity of the platinum. Thecatalyst layer 4 may include iridium in addition to the platinum and the iridium oxide. In this case, each of thecomposite particles 41 may include, in addition to theiridium oxide particles 412, at least one iridium particle bonded to theplatinum particle 411. Moreover, in thecatalyst layer 4, theplatinum particles 411 may be bonded to each other. The bonding state in thecatalyst layer 4 is not particularly limited. - The
catalyst layer 4 has a plurality ofrecesses 45 recessed from aprincipal surface 40 on an opposite side of thecatalyst layer 4 from theconductive substrate 2. In theelectrolysis electrode 1, thecatalyst layer 4 is partially exposed in the plurality ofrecesses 45. Each of the plurality ofrecesses 45 is, for example, a crack formed in thecatalyst layer 4. More specifically, each of the plurality ofrecesses 45 is a crack which is linear in plan view in the thickness direction defined with respect to thecatalyst layer 4. The plurality of cracks (recesses 45) have different shapes. Moreover, each crack may be formed along the thickness direction defined with respect to thecatalyst layer 4 or may have a bent on the way in the thickness direction defined with respect to thecatalyst layer 4. - The depth of each of the plurality of
recesses 45 is, for example, greater than or equal to 0.1 µm. The depth of each of the plurality ofrecesses 45 may be a depth reaching theintermediate layer 3 or may be a depth not reaching theintermediate layer 3. In theelectrolysis electrode 1 according to the embodiment, the plurality ofrecesses 45 do not extend through theintermediate layer 3, and the entirety of the firstprincipal surface 21 of theconductive substrate 2 is covered with theintermediate layer 3. In plan view in the thickness direction defined with respect to theconductive substrate 2, the width of each of the plurality ofrecesses 45 is greater than or equal to 0.1 µm and less than or equal to 10 µm and is preferably greater than or equal to 0.3 µm and less than or equal to 3 µm. The width of eachrecess 45 in plan view in the thickness direction defined with respect to theconductive substrate 2 is an opening width in a short direction (in a direction orthogonal to the length direction) on theprincipal surface 40 of thecatalyst layer 4. In plan view in the thickness direction defined with respect to theconductive substrate 2, the length of each of the plurality ofrecesses 45 is shorter than the length of each side of theconductive substrate 2. - The thickness of the
catalyst layer 4 is, for example, within a range of 0.1 µm to 10 µm. - Moreover, in plan view in the thickness direction defined with respect to the
conductive substrate 2, the percentage of S2 to (S1+S2) is, for example, higher than or equal to 5% and lower than or equal to 50%, where S1 is the area of theprincipal surface 40 of thecatalyst layer 4, and S2 is the total area of opening areas of the plurality ofrecesses 45 in theprincipal surface 40 of thecatalyst layer 4. The percentage of S2 to (S1+S2) is preferably higher than or equal to 5% to improve the production efficiency of chlorine. Moreover, the percentage of S2 to (S1+S2) is preferably lower than or equal to 50%, more preferably lower than or equal to 20%, to suppress, for example, peel-off of thecatalyst layer 4. That is, the percentage of S2 to (S1+S2) is more preferably higher than or equal to 5% and lower than or equal to 20%. - The
tantalum oxide layer 5 has a function of suppressing elution of the iridium oxide of thecatalyst layer 4. - As shown in
FIG. 1B , thetantalum oxide layer 5 has afirst portion 51 provided on theprincipal surface 40 of thecatalyst layer 4 and asecond portion 52 provided on an inner surface 451 of at least onerecess 45 of the plurality ofrecesses 45 in thecatalyst layer 4. Thetantalum oxide layer 5 preferably has thesecond portion 52 on the inner surface 451 of each of the plurality ofrecesses 45 in thecatalyst layer 4. - The molar quantity of tantalum in the
tantalum oxide layer 5 and iridium in the iridium oxide is preferably lower than or equal to 60% of the total molar quantity of the molar quantity of the iridium and the molar quantity of the platinum. - The
electrolysis electrode 1 further includestantalum oxide 43 provided in least onepore 42 of the plurality ofpores 42, and thetantalum oxide 43 is in contact with thecatalyst layer 4. Thetantalum oxide 43 is formed, for example, at the time of forming thetantalum oxide layer 5. Thetantalum oxide 43 is in contact with thecomposite particles 41 of thecatalyst layer 4. - With reference to
FIGS. 3A to 3D , an example of the manufacturing method of theelectrolysis electrode 1 will be described. - In the manufacturing method of the
electrolysis electrode 1, theconductive substrate 2 is prepared at first, and then, a surface roughening step, an intermediate layer forming step, a catalyst layer forming step, and a tantalum oxide layer forming step are sequentially performed. - The surface roughening step includes immersing, for example, the
conductive substrate 2 in an oxalic acid aqueous solution, thereby roughening the firstprincipal surface 21 of the conductive substrate 2 (seeFIG. 3A ). The surface roughening step is not an essential step. Regarding the surface roughness of the firstprincipal surface 21 of theconductive substrate 2 after the surface roughening step, an arithmetic mean roughness Ra is, for example, 0.7 µm, and a maximum height Rz is 7 µm. The arithmetic mean roughness Ra and the maximum height Rz may be values measured with a surface roughness meter of Zygo Co. - The intermediate layer forming step includes forming the
intermediate layer 3 on the firstprincipal surface 21 of the conductive substrate 2 (seeFIG. 3B ). Theintermediate layer 3 is, for example, a platinum layer. The intermediate layer forming step includes applying a solution which will be theintermediate layer 3 and then performing a heating process, and thereafter, baking the solution, thereby forming theintermediate layer 3. The solution is a solution obtained by dissolving a platinum compound in a solvent. The solvent is, for example, liquid obtained by mixing ethylene glycol monoethyl ether and hydrochloric acid and ethanol. The platinum compound is, for example, but not limited to, chloroplatinic acid, and the platinum compound may be, for example, platinum chloride. The formation method of theintermediate layer 3 is not limited to the examples described above but may be, for example, a vapor-deposition method, a sputtering method, a CVD method, or a plating method. - The catalyst layer forming step includes forming the
catalyst layer 4 on the intermediate layer 3 (seeFIG. 3C ). The catalyst layer forming step includes a first step and a second step. - The first step of the catalyst layer forming step includes performing an application step at least once and a drying step at least once, thereby forming a catalyst material layer which will be the
catalyst layer 4 on theintermediate layer 3 on theconductive substrate 2. The number of times of performing the application step and the drying step is determined based on, for example, a prescribed thickness of thecatalyst layer 4. Regarding the number of times of performing the application step and the drying step, the number of times of performing the application step and the drying step is at least increased as the prescribed thickness of thecatalyst layer 4 increases. For example, in the catalyst layer forming step, a first specified number of times (e.g., eight times) of application steps and the first specified number of times of drying steps are alternately repeated one by one, thereby forming the catalyst material layer which will be thecatalyst layer 4 on theintermediate layer 3 on theconductive substrate 2. - In the first step of the catalyst layer forming step, a solution (hereinafter referred to as a first solution) including the platinum compound which will be the
catalyst layer 4 and the iridium compound is directly or indirectly applied onto theintermediate layer 3 on the conductive substrate 2 (the application step is performed), and then, a heating process of drying the first solution by heating under a first condition (the drying step) is performed at least once (e.g., eight times), thereby forming the catalyst material layer which will be thecatalyst layer 4. The first solution is a solution obtained by dissolving the platinum compound and the iridium compound in a solvent (hereinafter referred to as a first solvent). The first solvent is, for example, liquid obtained by mixing ethylene glycol monoethyl ether and hydrochloric acid and ethanol. The platinum compound is, for example, but not limited to, chloroplatinic acid, and the platinum compound may be, for example, platinum chloride. The chloroplatinic acid is, for example, hydrogen hexachloroplatinate(IV) n-hydrate. The iridium compound is, for example, but not limited to, chloroiridic acid, and the iridium compound may be, for example, iridium chloride or iridium nitrate. The chloroiridic acid is, for example, hexachloroiridate(IV) n-hydrate. The metal concentration (the total concentration of platinum and iridium) of the first solution is, for example, 50 mg/mL. Moreover, the application quantity of the first solution is, for example, 2 µL/cm2. The first condition includes a heat process temperature and a heat process time. The heat process temperature in the first condition is within a range of 100°C to 400°C, for example, and may be 220°C as an example. Moreover, the heat process time in the first condition is within a range of 5 minutes to 15 minutes, for example, and may be 10 minutes as an example. - In the second step of the catalyst layer forming step, a heat process of baking the catalyst material layer under a prescribed baking condition is performed, thereby forming the
catalyst layer 4 and the plurality of cracks (the recesses 45) (seeFIG. 3C ). The baking condition includes a baking temperature and a baking time. The baking temperature is within a range of 500°C to 700°C, for example, and may be 560°C as an example. The baking time is within a range of 5 minutes to 20 minutes, for example, and may be 10 minutes as an example. - The tantalum oxide layer forming step includes forming the
tantalum oxide layer 5 on the catalyst layer 4 (seeFIG. 3D ). The tantalum oxide layer forming step includes a first step and a second step. - The first step of the tantalum oxide layer step includes performing an application step at least once and a drying step at least once, thereby forming a material layer which will be the
tantalum oxide layer 5 on thecatalyst layer 4. The number of times of performing the application step and the drying step is determined based on, for example, a prescribed thickness of thetantalum oxide layer 5. Regarding the number of times of performing the application step and the drying step, the number of times of performing the application step and the drying step is at least increased as the prescribed thickness of thetantalum oxide layer 5 increases. For example, in the tantalum oxide layer forming step, the application step is performed a second specified number of times (e.g., once) and the drying step is performed the second specified number of times, thereby forming the material layer which will be thetantalum oxide layer 5 on thecatalyst layer 4. - In the first step of the tantalum oxide layer forming step, a solution (hereinafter referred to as a second solution) including a tantalum compound which will be the
tantalum oxide layer 5 is applied onto the catalyst layer 4 (that is, the application step is performed), and then a heat process of drying the second solution by heating under the second condition (the drying step) is performed at least once (e.g., once), thereby forming the metal layer which will be thetantalum oxide layer 5. The second solution is a solution obtained by dissolving the tantalum compound in a solvent (hereinafter referred to as a second solvent). The second solvent is, for example, liquid obtained by mixing ethylene glycol monoethyl ether and hydrochloric acid and ethanol. The tantalum compound is, for example, but not limited to, tantalum chloride, and the tantalum compound may be, for example, tantalum ethoxide. The metal concentration (tantalum concentration) of the second solution is, for example, 50 mg/L. Moreover, the application quantity of the second solution is, for example, 1 µL/cm2. The second condition includes a heat process temperature and a heat process time. The heat process temperature in the second condition is within a range of 100°C to 400°C and may be 220°C as an example. Moreover, the heat process time in the second condition is within a range of 5 minutes to 15 minutes, for example, and may be 10 minutes as an example. - In the second step of the tantalum oxide layer forming step, the heat process of baking the material layer under a prescribed baking condition is performed, thereby forming the tantalum oxide layer 5 (see
FIG. 3D ). The baking condition includes a baking temperature and a baking time. The baking temperature is within a range of 500°C to 700°C, for example, and may be 560°C as an example. The baking time is within a range of 5 minutes to 20 minutes, for example, and may be 10 minutes as an example. - In the manufacturing method of the
electrolysis electrode 1 described above, thetantalum oxide 43 in at least one of thepores 42 in thecatalyst layer 4 is formed in the tantalum oxide layer forming step. -
FIG. 5 is a graph of results of a durability test conducted on anelectrolysis electrode 1 according to Example of the embodiment, an electrolysis electrode according to Comparative Example 1, and anelectrolysis electrode 1r (seeFIG. 4 ) according to Comparative Example 2. - The electrolysis electrode according to Comparative Example 1 is different from the
electrolysis electrode 1 according to Example in that Comparative Example 1 does not include the tantalum oxide layer of theelectrolysis electrode 1 according to Example. Theelectrolysis electrode 1r according to Comparative Example 2 includes 15tantalum oxide layers 6 and 15 catalyst layers 7 alternately stacked one by one instead of thecatalyst layer 4 and thetantalum oxide layer 5 of theelectrolysis electrode 1 according to the embodiment. InFIG. 4 , only three of thetantalum oxide layers 6 and only three of the catalyst layers 7 are shown. In theelectrolysis electrode 1r according to Comparative Example 2, the total catalyst amount of the 15 catalyst layers 7 is the same as the catalyst amount of theelectrolysis electrode 1 according to Example. Thecatalyst layer 7 includes platinum and iridium oxide. In theelectrolysis electrode 1r according to Comparative Example 2, a composite layer including the 15tantalum oxide layers 6 and the 15 catalyst layers 7 has a plurality of cracks. - The durability test is accelerated testing. The durability test was performed in which two electrolysis electrodes 1 (or two electrolysis electrodes or two
electrolysis electrodes 1r) formed under the same condition were adopted as pair of electrodes, and the pair of electrodes were immersed in salt water in an electrolytic bath in a durability test facility. In the durability test, polarity reversal was performed each time the pair of electrodes are energized for a predetermined time (3 minutes). In this case, the polarity reversal means that a combination of the anode and the cathode in the pair of electrodes is reversed. In other words, the polarity reversal means that an electrode of the pair of electrodes which is on a high-potential side is changed such that an electrode used as the anode and an electrode used as the cathode are respectively used as the cathode and the anode. The electrolytic bath in the durability test facility has a water inlet and a water outlet for salt water. In the durability test, salt water is added so that the electric conductivity of the salt water in the electrolytic bath is 1650±165 µS/cm. Moreover, in the durability test, the electrolytic bath in the durability test facility is drained while tap water is constantly supplied to the electrolytic bath at a flow rate of 2 L/min. The salt water supplied to the electrolytic bath in the durability test facility is a sodium chloride solution obtained by dissolving salt (sodium chloride) in tap water. The current value of an energization current in the durability test is 400 mA. For measuring the hypochlorous acid water concentration, the electrodes were taken out of the electrolytic bath in the durability test facility at the time of measuring the hypochlorous acid water concentration, and the hypochlorous acid water concentration was measured as described below. As salt water in an electrolytic bath for measuring a hypochlorous acid water concentration, salt water produced by dissolving 4.5 g salt (sodium chloride) in 800 mL pure water was used. The current value of an energization current for measuring the hypochlorous acid water concentration is 400 mA. Moreover, in initial aging, the polarity reversal was performed each time the pair of electrodes were energized for a predetermined time (3 minutes), and in this way, the pair of electrodes were energized for a total of 12 minutes. After the initial aging, electrolysis was performed for 12 minutes under the same condition as the initial aging, and then, some of the electrolysis water was taken out every 3 minutes, and the hypochlorous acid water concentration was measured. For the hypochlorous acid water concentration, the free chlorine concentration (HOCl, OCl-) was measured by a pocket residual chlorine meter (HACH, Pocket Colorimeter II 58700-00) based on the DPD method. In this case, the polarity reversal means that a combination of the anode and the cathode in the pair of electrodes is reversed. In other words, the polarity reversal means that an electrode of the pair of electrodes which is on a high-potential side is changed such that an electrode used as the anode and an electrode used as the cathode are respectively used as the cathode and the anode. - The abscissa in
FIG. 5 represents a durability test time (elapsed time). The ordinate inFIG. 5 represents the hypochlorous acid water concentration measured after the energization for a unit time (3 minutes) was performed at the time. In this case, chlorine produced in the vicinity of the anode contributes to production of hypochlorous acid, and therefore, the hypochlorous acid water concentration is substantially determined based on the amount of the chlorine produced per unit time. - From
FIG. 5 , it can be seen that in theelectrolysis electrode 1 according to Example, the hypochlorous acid water concentration is higher and a time until the hypochlorous acid water concentration decreases to or less than a prescribed value (e.g., 5 mg/L) is longer (the durability is improved more) than in the electrolysis electrode according to Comparative Example 1 and theelectrolysis electrode 1r according to Comparative Example 2. Note that the durability is determined based on elution caused by consumption of thecatalyst layer 4, peel-off of thecatalyst layer 4, or the like. In theelectrolysis electrode 1r according to Comparative Example 2, thetantalum oxide layers 6 and the catalyst layers 7 are alternately stacked, and therefore, a conduction path and a path of gas are narrow, the amount of chlorine produced per unit time is small, and the number of active points not used is large, and therefore, theelectrolysis electrode 1r is presumed to have reduced service life. In the electrolysis electrode according to Comparative Example 1, chlorine is more easily produced than in theelectrolysis electrode 1r according to Comparative Example 2, but the catalyst is more likely to desorb than in theelectrolysis electrode 1 according to Example, and therefore, the electrolysis electrode according to Comparative Example 1 is presumed to have shorter service life than theelectrolysis electrode 1 according to Example. In other words, it can be seen fromFIG. 5 that theelectrolysis electrode 1 according to Example is capable of producing a larger amount of chlorine and thus has a longer service life than the electrolysis electrode according to Comparative Example 1 and theelectrolysis electrode 1r according to Comparative Example 2. - The
electrolysis electrode 1 according to the embodiment includes thetantalum oxide layer 5 provided on thecatalyst layer 4 including platinum and iridium oxide, and thecatalyst layer 4 is partially exposed, which enables the durability to be improved. This enables theelectrolysis electrode 1 according to the embodiment to make thecatalyst layer 4 contribute to production of chlorine and to have improved durability compared to the case where the entirety of theprincipal surface 40 of thecatalyst layer 4 is in contact with salt water. Theelectrolysis electrode 1 according to the embodiment includes thetantalum oxide layer 5 and thetantalum oxide 43, which enables platinum iridium to be suppressed from being excessively consumed (eluted) from thecatalyst layer 4 during use, thereby suppressing a rapid structural change in thecatalyst layer 4, and partial desorption of thecatalyst layer 4 and peel-off of thecatalyst layer 4 can be suppressed. Moreover, in theelectrolysis electrode 1 according to the embodiment, the agglomeration of iridium can be suppressed. - Further, the
electrolysis electrode 1 according to the embodiment includes thetantalum oxide 43 which is provided in the plurality ofpores 42 in thecatalyst layer 4 and which is in contact with thecatalyst layer 4, which enables the mechanical intensity of thecatalyst layer 4 to be improved and enables excessive consumption of iridium oxide, agglomeration of the iridium oxide, and the like to be suppressed. - The embodiment is a mere example of various embodiments of the present disclosure. Various modifications may be made to the embodiment depending on design and the like as long as the object of the present disclosure is achieved.
- For example, the shape of the
conductive substrate 2 in plan view is not limited to a rectangular shape, but may be, for example, a square shape. - Moreover, the
catalyst layer 4 is not limited to a porous layer but may be a non-porous layer. - Further, the plurality of
recesses 45 may have the same shape. In this case, for example, in the manufacturing method of theelectrolysis electrode 1, the plurality ofrecess 45 may be formed by an etching technique, a laser processing technique, or the like. Using these techniques provides the advantages that the degree of freedom of design in terms of the layout and the size of the plurality ofrecesses 45 is increased and the reproducibility of formation locations of the plurality ofrecesses 45 is increased. - Moreover, in the
electrolysis electrode 1, thecatalyst layer 4 does not have to have the plurality ofrecesses 45, and in this case, for example, thetantalum oxide layer 5 has at least a plurality of holes (e.g., pin holes or cracks) through which theprincipal surface 40 of thecatalyst layer 4 is partially exposed. - Moreover, in the
electrolysis electrode 1, even in the case of thecatalyst layer 4 having the plurality ofrecesses 45, thetantalum oxide layer 5 may have a plurality of cracks through which thecatalyst layer 4 is partially exposed. In the manufacturing method of theelectrolysis electrode 1 described above, if the thickness of thetantalum oxide layer 5 is greater than or equal to 50 nm, cracks through which thecatalyst layer 4 is partially exposed may be formed in thetantalum oxide layer 5 in the second step of the tantalum oxide layer forming step. Moreover, in the manufacturing method of theelectrolysis electrode 1 described above, cracks may be formed in the tantalum oxide layer in the second step of the tantalum oxide layer forming step, and in addition, cracks continuous with the cracks in the tantalum oxide layer may be formed in thecatalyst layer 4. The plurality of holes in thetantalum oxide layer 5 may be formed by an etching technique, a laser processing technique, or the like. - The
electrolysis electrode 1 may include a titanium oxide layer provided between theconductive substrate 2 and theintermediate layer 3. - The
tantalum oxide layer 5 may include tantalum in addition to the tantalum oxide. In other words, thetantalum oxide layer 5 may be a layer in which tantalum oxide and tantalum are included. - Moreover, the
electrolysis electrode 1 may further include, on the secondprincipal surface 22 of theconductive substrate 2, a structural component similar to a structural component including theintermediate layer 3, thecatalyst layer 4, and thetantalum oxide layer 5 at the side of the firstprincipal surface 21. - The embodiment and the like described above disclose the following aspects in the present specification.
- An electrolysis electrode (1) of a first aspect includes a conductive substrate (2), a catalyst layer (4), and a tantalum oxide layer (5). The conductive substrate (2) includes at least titanium. The catalyst layer (4) is provided on the conductive substrate (2). The catalyst layer (4) includes platinum and iridium oxide. The tantalum oxide layer (5) is provided on the catalyst layer (4). In the electrolysis electrode (1), the catalyst layer (4) is partially exposed.
- The electrolysis electrode (1) of the first aspect has improved durability.
- In an electrolysis electrode (1) of a second aspect referring to the first aspect, the catalyst layer (4) is a porous layer including: a plurality of composite particles (41) each including platinum (a platinum particle 411) and iridium oxide (iridium oxide particles 412); and a plurality of pores (42). The electrolysis electrode (1) further includes tantalum oxide (43) provided in at least one pore (42) of the plurality of pores (42), and the tantalum oxide (43) is in contact with the catalyst layer (4).
- The electrolysis electrode (1) according to the second aspect has improved production efficiency of chlorine with improved durability.
- In an electrolysis electrode (1) of a third aspect referring to the first or second aspect, the catalyst layer (4) has a plurality of recesses (45) recessed from a principal surface (40) on an opposite side of the catalyst layer (4) from the conductive substrate (2). The tantalum oxide layer (5) has: a first portion (51) provided on the principal surface (40) of the catalyst layer (4); and a second portion (52) provided on an inner surface (451) of at least one recess (45) of the plurality of recesses (45) in the catalyst layer (4).
- The electrolysis electrode (1) according to the third aspect has improved production efficiency of chlorine with improved durability.
- In an electrolysis electrode (1) of a fourth aspect referring to the third aspect, the catalyst layer (4) is partially exposed in the plurality of recesses (45).
- In the electrolysis electrode (1) of the fourth aspect, salt water easily enters the catalyst layer (4) in an in-plane direction of the catalyst layer (4) through the inner surface (451) of the at least one recess (45), the inner surface (451) being exposed through the at least one recess (45). Thus, it is presumed that in the electrolysis electrode (1) of the fourth aspect, the catalyst layer (4) readily contributes to production of chlorine, which enables the durability to be improved.
- An electrolysis electrode (1) of a fifth aspect referring to any one of the first to fourth aspects further includes an intermediate layer (3). The intermediate layer (3) is provided between the conductive substrate (2) and the catalyst layer (4). The intermediate layer (3) includes platinum.
- In the electrolysis electrode (1) of the fifth aspect, peel-off of a plurality of catalyst layers (4) is suppressed, which enables the durability to be improved.
- In an electrolysis electrode (1) of a sixth aspect referring to the fifth aspect, the conductive substrate (2) has a principal surface (a first principal surface 21) facing the catalyst layer (4), and the principal surface is a rough surface.
- In the electrolysis electrode (1) of the sixth aspect, adhesiveness between the conductive substrate (2) and the intermediate layer (3) is improved, which enables the catalyst layer (4) to be suppressed from peeling off from a side of the conductive substrate (2), thereby improving the durability.
-
- 1
- Electrolysis Electrode
- 2
- Conductive Substrate
- 21
- First Principal Surface
- 3
- Intermediate Layer
- 4
- Catalyst Layer
- 40
- Principal Surface
- 41
- Composite Particle
- 411
- Platinum Particle
- 412
- Iridium Oxide Particle
- 42
- Pore
- 43
- Tantalum Oxide
- 45
- Recess
- 451
- Inner Surface
- 5
- Tantalum Oxide Layer
- 51
- First Portion
- 52
- Second Portion
Claims (6)
- An electrolysis electrode, comprising:a conductive substrate including at least titanium;a catalyst layer provided on the conductive substrate and including platinum and iridium oxide; anda tantalum oxide layer provided on the catalyst layer,the catalyst layer being partially exposed.
- The electrolysis electrode of claim 1, whereinthe catalyst layer is a porous layer includinga plurality of composite particles each including platinum and iridium oxide anda plurality of pores, andthe electrolysis electrode further includes tantalum oxide provided in at least one pore of the plurality of pores, the tantalum oxide being in contact with the catalyst layer.
- The electrolysis electrode of claim 1 or 2, whereinthe catalyst layer has a plurality of recesses recessed from a principal surface on an opposite side of the catalyst layer from the conductive substrate,the tantalum oxide layer hasa first portion provided on the principal surface in the catalyst layer anda second portion provided on an inner surface of at least one recess of the plurality of recesses in the catalyst layer.
- The electrolysis electrode of claim 3, wherein
the catalyst layer is partially exposed in the plurality of recesses. - The electrolysis electrode of any one of claims 1 to 4, further comprising
an intermediate layer provided between the conductive substrate and the catalyst layer, the intermediate layer including platinum. - The electrolysis electrode of claim 5, wherein
the conductive substrate has a principal surface facing the catalyst layer, the principal surface being a rough surface.
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PCT/JP2020/035612 WO2021117311A1 (en) | 2019-12-13 | 2020-09-18 | Electrolysis electrode |
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WO2023188704A1 (en) * | 2022-03-29 | 2023-10-05 | パナソニックIpマネジメント株式会社 | Electrolysis electrode |
WO2023188992A1 (en) * | 2022-03-31 | 2023-10-05 | パナソニックIpマネジメント株式会社 | Electrode for electrolysis and hypochlorous acid generation device |
WO2023188991A1 (en) * | 2022-03-31 | 2023-10-05 | パナソニックIpマネジメント株式会社 | Electrode for electrolysis and hypochlorous acid generation device |
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CN1156612C (en) * | 2000-09-30 | 2004-07-07 | 华东师范大学 | Non-crack nm-class Ti-based anode and its preparing process |
JP2004323955A (en) * | 2003-04-28 | 2004-11-18 | Wako Sangyo:Kk | Electrode for electrolysis, and manufacturing method therefor |
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KR101079689B1 (en) * | 2009-01-20 | 2011-11-04 | 한국기계연구원 | Mixed Metal Oxide Electrode For Making Sterilized Water With Hypochlorous Acid And Manufacturing Method Thereof |
KR20140047371A (en) * | 2012-10-12 | 2014-04-22 | 주식회사 그렌텍 | Electrode plate for creating sterilized water having hydrophile coating layer |
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