CA2859939A1 - High-load durable anode for oxygen generation and manufacturing method for the same - Google Patents
High-load durable anode for oxygen generation and manufacturing method for the same Download PDFInfo
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- CA2859939A1 CA2859939A1 CA2859939A CA2859939A CA2859939A1 CA 2859939 A1 CA2859939 A1 CA 2859939A1 CA 2859939 A CA2859939 A CA 2859939A CA 2859939 A CA2859939 A CA 2859939A CA 2859939 A1 CA2859939 A1 CA 2859939A1
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- catalyst layer
- degrees celsius
- iridium oxide
- metal substrate
- conductive metal
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 54
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 54
- 239000001301 oxygen Substances 0.000 title claims abstract description 54
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 24
- 239000003054 catalyst Substances 0.000 claims abstract description 154
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 claims abstract description 124
- 229910000457 iridium oxide Inorganic materials 0.000 claims abstract description 100
- 229910052751 metal Inorganic materials 0.000 claims abstract description 62
- 239000002184 metal Substances 0.000 claims abstract description 62
- 239000000758 substrate Substances 0.000 claims abstract description 56
- 239000011248 coating agent Substances 0.000 claims abstract description 39
- 238000000576 coating method Methods 0.000 claims abstract description 39
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 23
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims description 16
- 239000010936 titanium Substances 0.000 claims description 16
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 15
- 229910052719 titanium Inorganic materials 0.000 claims description 15
- 230000015572 biosynthetic process Effects 0.000 claims description 7
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 7
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- 238000007733 ion plating Methods 0.000 claims description 5
- 239000004615 ingredient Substances 0.000 claims description 4
- 238000005868 electrolysis reaction Methods 0.000 abstract description 52
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 7
- 239000011889 copper foil Substances 0.000 abstract description 6
- 238000000605 extraction Methods 0.000 abstract description 5
- 239000007788 liquid Substances 0.000 abstract description 5
- 229910000831 Steel Inorganic materials 0.000 abstract description 4
- 229910052782 aluminium Inorganic materials 0.000 abstract description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 4
- 239000010959 steel Substances 0.000 abstract description 4
- 239000011888 foil Substances 0.000 abstract description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 38
- 239000000047 product Substances 0.000 description 38
- 239000000243 solution Substances 0.000 description 17
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 10
- 239000013078 crystal Substances 0.000 description 9
- 238000002441 X-ray diffraction Methods 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 8
- 230000003247 decreasing effect Effects 0.000 description 8
- 238000011156 evaluation Methods 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910001362 Ta alloys Inorganic materials 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 235000011149 sulphuric acid Nutrition 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000002484 cyclic voltammetry Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 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 description 3
- 229910001936 tantalum oxide Inorganic materials 0.000 description 3
- 108010010803 Gelatin Proteins 0.000 description 2
- 229910001069 Ti alloy Inorganic materials 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000002425 crystallisation Methods 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003487 electrochemical reaction Methods 0.000 description 2
- 238000005363 electrowinning Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229920000159 gelatin Polymers 0.000 description 2
- 239000008273 gelatin Substances 0.000 description 2
- 235000019322 gelatine Nutrition 0.000 description 2
- 235000011852 gelatine desserts Nutrition 0.000 description 2
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910000464 lead oxide Inorganic materials 0.000 description 2
- MINVSWONZWKMDC-UHFFFAOYSA-L mercuriooxysulfonyloxymercury Chemical compound [Hg+].[Hg+].[O-]S([O-])(=O)=O MINVSWONZWKMDC-UHFFFAOYSA-L 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000006259 organic additive Substances 0.000 description 2
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- OEIMLTQPLAGXMX-UHFFFAOYSA-I tantalum(v) chloride Chemical compound Cl[Ta](Cl)(Cl)(Cl)Cl OEIMLTQPLAGXMX-UHFFFAOYSA-I 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000001149 thermolysis Methods 0.000 description 2
- KPZGRMZPZLOPBS-UHFFFAOYSA-N 1,3-dichloro-2,2-bis(chloromethyl)propane Chemical compound ClCC(CCl)(CCl)CCl KPZGRMZPZLOPBS-UHFFFAOYSA-N 0.000 description 1
- 229910021639 Iridium tetrachloride Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000002050 diffraction method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- RVPVRDXYQKGNMQ-UHFFFAOYSA-N lead(2+) Chemical compound [Pb+2] RVPVRDXYQKGNMQ-UHFFFAOYSA-N 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- CALMYRPSSNRCFD-UHFFFAOYSA-J tetrachloroiridium Chemical compound Cl[Ir](Cl)(Cl)Cl CALMYRPSSNRCFD-UHFFFAOYSA-J 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- -1 titanium Chemical class 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- 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
- C25B1/02—Hydrogen or oxygen
- C25B1/04—Hydrogen or oxygen by electrolysis of water
-
- 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
- C25B11/053—Electrodes comprising one or more electrocatalytic coatings on a substrate characterised by multilayer electrocatalytic coatings
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
- C23C14/32—Vacuum evaporation by explosion; by evaporation and subsequent ionisation of the vapours, e.g. ion-plating
-
- 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
- C25B1/02—Hydrogen or oxygen
-
- 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
-
- 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
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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
- C25B11/073—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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
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- Organic Chemistry (AREA)
- Electrochemistry (AREA)
- Inorganic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Catalysts (AREA)
- Electrolytic Production Of Metals (AREA)
- Laminated Bodies (AREA)
Abstract
The present invention aims to provide a high-load durable anode for oxygen generation and a manufacturing method for the same used for industrial electrolyses including manufacturing of electrolytic metal foils such as electrolytic copper foil, aluminum liquid contact and continuously electrogalvanized steel plate, and metal extraction, having superior durability under high-load electrolysis conditions. The present invention features an anode for oxygen generation and a manufacturing method for the same comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more, the coating is baked in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius to form the catalyst layer containing amorphous iridium oxide and the catalyst layer containing the amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to crystallize almost all amount of iridium oxide in the catalyst layer.
Description
DESCRIPTION
Title of Invention HIGH-LOAD DURABLE ANODE FOR OXYGEN GENERATION AND
MANUFACTURING METHOD FOR THE SAME
Technical Field The present invention relates to an anode for oxygen generation used for various industrial electrolyses and a manufacturing method for the same; more in detail, it relates to a high-load durable anode for oxygen generation and a manufacturing method for the same used for industrial electrolyses including manufacturing of electrolytic metal foils such as electrolytic copper foil, aluminum liquid contact, and continuously electrogalvanized steel plate, and metal extraction, having superior durability under high-load electrolysis conditions.
Background Art In industrial electrolyses including manufacturing of electrolytic copper foil, aluminum liquid contact, continuously electrogalvanized steel plate and metal extraction, oxygen generation is involved at the anode. For this reason, the anode which is coated chiefly with iridium oxide having durability to oxygen generation, as electrode catalyst, on the titanium metal substrate has been widely applied.
Generally speaking, in this type of industrial electrolysis involving oxygen generation at the anode, electrolysis is usually performed at a constant electric current in view of production efficiency, energy saving, etc. Current density has been in a range from several A/dm2 mainly applied in the industrial fields including metal extraction to 100A/dm2 at maximum for manufacturing electrolytic copper foil.
However, nowadays, it is often seen that electrolysis is performed at a current density of 300A/dm2 - 700A/dm2 or more for higher product quality or for providing special performance characteristics. Such high electric current is not supplied to all the anodes installed to the industrial electrolysis system, but rather, it is considered that an anode is installed as an auxiliary one at a specific point where high-load electrolysis condition is applied to provide special performance characteristics to the product obtained from the electrolysis.
Under the electrolysis at such a high current density, the electrode catalyst layer is highly loaded and electric current tends to be concentrated there, causing rapid consumption of the electrode catalyst layer. Moreover, organic substances or impurity elements added for stabilizing products cause various electrochemical and chemical reactions, the concentration of hydrogen ion increases resulting from the oxygen generation reaction, lowering the pH value, and consumption of electrode catalyst is expedited.
One solution to solve these problems may be to increase the surface area of the electrode catalyst layer so as to decrease the actual electric current load. For instance, one solution is to apply a substrate of mesh or punched metal, instead of conventional plate substrates, to increase the surface area physically. Use of these substrates, however, involves undesirable extra processing costs.
Furthermore, actual current density decreased by physically increased surface area of the substrate does not improve the electric current concentration at the electrode catalyst layer, resulting in little suppression effect on catalyst consumption.
In the thermolysis formation method of the electrode catalyst layer by repeating coating and baking, if the amount of coating iridium per time is increased, it is simply considered that the formed catalyst layer is soft and fluffy; but by this method only, increase in the effective surface area of the catalyst layer of the electrode is limited and improvements in consumption of the catalyst layer under high-load conditions and in durability could not be observed clearly.
Title of Invention HIGH-LOAD DURABLE ANODE FOR OXYGEN GENERATION AND
MANUFACTURING METHOD FOR THE SAME
Technical Field The present invention relates to an anode for oxygen generation used for various industrial electrolyses and a manufacturing method for the same; more in detail, it relates to a high-load durable anode for oxygen generation and a manufacturing method for the same used for industrial electrolyses including manufacturing of electrolytic metal foils such as electrolytic copper foil, aluminum liquid contact, and continuously electrogalvanized steel plate, and metal extraction, having superior durability under high-load electrolysis conditions.
Background Art In industrial electrolyses including manufacturing of electrolytic copper foil, aluminum liquid contact, continuously electrogalvanized steel plate and metal extraction, oxygen generation is involved at the anode. For this reason, the anode which is coated chiefly with iridium oxide having durability to oxygen generation, as electrode catalyst, on the titanium metal substrate has been widely applied.
Generally speaking, in this type of industrial electrolysis involving oxygen generation at the anode, electrolysis is usually performed at a constant electric current in view of production efficiency, energy saving, etc. Current density has been in a range from several A/dm2 mainly applied in the industrial fields including metal extraction to 100A/dm2 at maximum for manufacturing electrolytic copper foil.
However, nowadays, it is often seen that electrolysis is performed at a current density of 300A/dm2 - 700A/dm2 or more for higher product quality or for providing special performance characteristics. Such high electric current is not supplied to all the anodes installed to the industrial electrolysis system, but rather, it is considered that an anode is installed as an auxiliary one at a specific point where high-load electrolysis condition is applied to provide special performance characteristics to the product obtained from the electrolysis.
Under the electrolysis at such a high current density, the electrode catalyst layer is highly loaded and electric current tends to be concentrated there, causing rapid consumption of the electrode catalyst layer. Moreover, organic substances or impurity elements added for stabilizing products cause various electrochemical and chemical reactions, the concentration of hydrogen ion increases resulting from the oxygen generation reaction, lowering the pH value, and consumption of electrode catalyst is expedited.
One solution to solve these problems may be to increase the surface area of the electrode catalyst layer so as to decrease the actual electric current load. For instance, one solution is to apply a substrate of mesh or punched metal, instead of conventional plate substrates, to increase the surface area physically. Use of these substrates, however, involves undesirable extra processing costs.
Furthermore, actual current density decreased by physically increased surface area of the substrate does not improve the electric current concentration at the electrode catalyst layer, resulting in little suppression effect on catalyst consumption.
In the thermolysis formation method of the electrode catalyst layer by repeating coating and baking, if the amount of coating iridium per time is increased, it is simply considered that the formed catalyst layer is soft and fluffy; but by this method only, increase in the effective surface area of the catalyst layer of the electrode is limited and improvements in consumption of the catalyst layer under high-load conditions and in durability could not be observed clearly.
As an electrode for this kind of electrolysis, electrode with a low oxygen generation potential and a long service life is required. Conventionally, as electrode of this type, an insoluble electrode comprising a conductive metal substrate, such as titanium, covered with a catalyst layer containing precious metal or precious metal oxide has been applied. For example, PTL 1 discloses an insoluble electrode prepared in such a manner that a catalyst layer containing iridium oxide and valve metal oxide is coated on a substrate of conductive metals, such as titanium, heated in oxidizing atmosphere and baked at a temperature of 650 degrees Celsius - 850 degrees Celsius, to crystallize valve metal oxide partially. This electrode, however, has the following drawbacks. Since the electrode is baked at a temperature of 650 degrees Celsius or more, the metal substrate, such as of titanium causes interfacial corrosion, and becomes poor conductor, causing oxygen overvoltage to increase to an unserviceable degree as electrode. Moreover, the crystallite diameter of iridium oxide in the catalyst layer enlarges, resulting in decreased effective surface area of the catalyst layer, leading to a poor catalytic activity.
PTL 2 discloses use of an anode for copper plating and copper foil manufacturing prepared in such a manner that a catalyst layer comprising amorphous iridium oxide and amorphous tantalum oxide in a mixed state is provided on a substrate of conductive metal, such as titanium. This electrode, however, features amorphous iridium oxide, and is insufficient in electrode durability. The reason why durability decreases when amorphous iridium oxide is applied is that amorphous iridium oxide shows unstable bonding between iridium and oxygen, compared with crystalline iridium oxide.
PTL 3 discloses an electrode coated with a catalyst layer comprising a double layer structure by a lower layer of crystalline iridium oxide and an upper layer of amorphous iridium oxide, in order to suppress consumption of the catalyst layer and to enhance durability of the electrode. The electrode disclosed by PTL 3 is insufficient in electrode durability because the upper layer of the catalyst layer is amorphous iridium oxide. Moreover, crystalline iridium oxide exists only in the lower layer, not uniformly distributed over the entire catalyst layer, resulting in insufficient electrode durability.
PTL 4 discloses an anode for zinc electrowinning in which a catalyst layer containing amorphous iridium oxide as a prerequisite and crystalline iridium oxide, as a mixed state is provided on a substrate of conductive metal like titanium.
PTL
5 discloses an anode for cobalt electrowinning in which a catalyst layer containing amorphous iridium oxide as a prerequisite and crystalline iridium oxide, as a mixed state is provided on a substrate of conductive metal like titanium.
However, it is thought that electrode durability of these two electrodes is not enough because they contain a large amount of amorphous iridium oxide, as prerequisite.
To solve these problems, the inventors of the present invention have developed, aiming chiefly at decreasing oxygen generation overvoltage for the case that the amount of coating of iridium per time is 2g/m2 or less, (1) the baking method to form a catalyst layer in which crystalline iridium oxide and amorphous iridium oxide coexist by low temperature baking (370 degrees Celsius - 400 degrees Celsius) plus high temperature post-bake (520 degrees Celsius - 600 degrees Celsius); and (2) the baking method to form a catalyst layer in which almost complete crystalline iridium oxide only is contained by high temperature baking (410 degrees Celsius - 450 degrees Celsius) plus high temperature post-bake (520 degrees Celsius - 560 degrees Celsius); and patent applications have been made for these two methods as of the same date with the present application.
According to these two inventions, lead adhesion resistivity can be achieved when the amount of iridium coating per time is 2g/m2 or less, in the electrolysis condition of current density not more than 100A/dm2, and at the same time, improvement of durability from increase of the effective area of catalyst layer and reduction of oxygen generation overvoltage can be achieved.
Recently, however, in order to enhance the quality of products or to provide special performance characteristics to products, electrolysis at a current density of 300A/dm2 ¨ 700A/dm2 or more has been frequently conducted. Recent trend is that such high electric current is not supplied to all the anodes installed to the industrial electrolysis system, but rather, an auxiliary anode is installed at a specific point where high-load electrolysis condition is applied to provide special performance characteristics to products obtained from the electrolysis.
Under the electrolysis at such a high current density, the electrode catalyst layer is highly loaded and electric current tends to be concentrated there, causing rapid consumption of the electrode catalyst layer. Moreover, organic substance or impurity elements added for stabilizing product quality cause various electrochemical and chemical reactions, the concentration of hydrogen ion increases in concomitant with the oxygen generation reaction, lowering the pH
value, and consumption of electrode catalyst is further expedited. From these phenomena, it became clear that the enhancement of durability by the increase of the effective area of catalyst layer and the reduction of oxygen generation overvoltage may not always be achieved by the inventions relating to the above-mentioned two patent applications by the inventors of the present invention.
Citation List Patent Literature PTL 1: JP2002-275697A (JP3654204B) PTL 2: JP2004-238697A (JP3914162B) PTL 3: JP2007-146215A
PTL 2 discloses use of an anode for copper plating and copper foil manufacturing prepared in such a manner that a catalyst layer comprising amorphous iridium oxide and amorphous tantalum oxide in a mixed state is provided on a substrate of conductive metal, such as titanium. This electrode, however, features amorphous iridium oxide, and is insufficient in electrode durability. The reason why durability decreases when amorphous iridium oxide is applied is that amorphous iridium oxide shows unstable bonding between iridium and oxygen, compared with crystalline iridium oxide.
PTL 3 discloses an electrode coated with a catalyst layer comprising a double layer structure by a lower layer of crystalline iridium oxide and an upper layer of amorphous iridium oxide, in order to suppress consumption of the catalyst layer and to enhance durability of the electrode. The electrode disclosed by PTL 3 is insufficient in electrode durability because the upper layer of the catalyst layer is amorphous iridium oxide. Moreover, crystalline iridium oxide exists only in the lower layer, not uniformly distributed over the entire catalyst layer, resulting in insufficient electrode durability.
PTL 4 discloses an anode for zinc electrowinning in which a catalyst layer containing amorphous iridium oxide as a prerequisite and crystalline iridium oxide, as a mixed state is provided on a substrate of conductive metal like titanium.
PTL
5 discloses an anode for cobalt electrowinning in which a catalyst layer containing amorphous iridium oxide as a prerequisite and crystalline iridium oxide, as a mixed state is provided on a substrate of conductive metal like titanium.
However, it is thought that electrode durability of these two electrodes is not enough because they contain a large amount of amorphous iridium oxide, as prerequisite.
To solve these problems, the inventors of the present invention have developed, aiming chiefly at decreasing oxygen generation overvoltage for the case that the amount of coating of iridium per time is 2g/m2 or less, (1) the baking method to form a catalyst layer in which crystalline iridium oxide and amorphous iridium oxide coexist by low temperature baking (370 degrees Celsius - 400 degrees Celsius) plus high temperature post-bake (520 degrees Celsius - 600 degrees Celsius); and (2) the baking method to form a catalyst layer in which almost complete crystalline iridium oxide only is contained by high temperature baking (410 degrees Celsius - 450 degrees Celsius) plus high temperature post-bake (520 degrees Celsius - 560 degrees Celsius); and patent applications have been made for these two methods as of the same date with the present application.
According to these two inventions, lead adhesion resistivity can be achieved when the amount of iridium coating per time is 2g/m2 or less, in the electrolysis condition of current density not more than 100A/dm2, and at the same time, improvement of durability from increase of the effective area of catalyst layer and reduction of oxygen generation overvoltage can be achieved.
Recently, however, in order to enhance the quality of products or to provide special performance characteristics to products, electrolysis at a current density of 300A/dm2 ¨ 700A/dm2 or more has been frequently conducted. Recent trend is that such high electric current is not supplied to all the anodes installed to the industrial electrolysis system, but rather, an auxiliary anode is installed at a specific point where high-load electrolysis condition is applied to provide special performance characteristics to products obtained from the electrolysis.
Under the electrolysis at such a high current density, the electrode catalyst layer is highly loaded and electric current tends to be concentrated there, causing rapid consumption of the electrode catalyst layer. Moreover, organic substance or impurity elements added for stabilizing product quality cause various electrochemical and chemical reactions, the concentration of hydrogen ion increases in concomitant with the oxygen generation reaction, lowering the pH
value, and consumption of electrode catalyst is further expedited. From these phenomena, it became clear that the enhancement of durability by the increase of the effective area of catalyst layer and the reduction of oxygen generation overvoltage may not always be achieved by the inventions relating to the above-mentioned two patent applications by the inventors of the present invention.
Citation List Patent Literature PTL 1: JP2002-275697A (JP3654204B) PTL 2: JP2004-238697A (JP3914162B) PTL 3: JP2007-146215A
PTL 4: JP2009-293117A (JP4516617B) PTL 5: JP2010-001556A (JP4516618B) Summary of Invention Technical Problem In order to solve the above-mentioned problems, the present invention aims to provide a high-load durable anode for oxygen generation and a manufacturing method for the same, having a superior durability under the conditions of high-load, which can improve current distribution to the electrode catalyst layer, suppress consumption of the electrode catalyst and improve durability of the electrode catalyst by enlarging effective surface area of the electrode catalyst layer under the conditions of high-load.
Solution to Problem As the first solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more, the coating is baked in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius to form the catalyst layer containing amorphous iridium oxide and the catalyst layer containing the amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius -600 degrees Celsius to crystallize almost all amount of iridium oxide in the catalyst layer.
As the second solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the degree of crystallinity of iridium oxide in the catalyst layer after the post-baking is made to be 80% or more.
As the third solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the crystallite diameter of iridium oxide in the catalyst layer is 9.0nm or less.
As the fourth solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein a base layer containing tantalum and titanium ingredients is formed by the arc ion plating (hereafter called AIP) process on the conductive metal substrate before the formation of the catalyst layer.
As the fifth solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation, wherein the amount of coating of iridium per time for a catalyst layer is 2 g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to crystallize almost all amount of iridium oxide in the catalyst layer.
As the sixth solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation, wherein the amount of coating of iridium per time for a catalyst layer is 2g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to make the degree of crystallinity of iridium oxide in the catalyst layer to be 80% or more.
As the seventh solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation, wherein the amount of coating of iridium per time for a catalyst layer is 2g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to make the crystallite diameter of iridium oxide in the catalyst layer to be 9.0nm or less.
As the eighth solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein an AIP base layer containing tantalum and titanium ingredients is formed by the AIP process on the conductive metal substrate before the formation of the catalyst layer.
Advantageous Effects of Invention In the formation for the electrode catalyst layer containing iridium oxide by the present invention, the amount of coating of iridium per time of the catalyst layer is 2g/m2 or more, baking is conducted, instead of the conventional repeated baking operations at 500 degrees Celsius or more, which are the perfect crystal deposition temperature, by two steps: baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius to form a catalyst layer containing amorphous iridium oxide and post-baking in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to suppress the crystallite diameter of iridium oxide in the electrode catalyst layer preferably to 9.0nm or less and to crystallize most of the iridium oxide preferably to 80% or more in crystallinity. Thus, the growth of crystallite diameter of iridium oxide was able to be suppressed and the effective surface area of the catalyst layer was able to be increased. Thus, according to the present invention, the growth of crystallite diameter of iridium oxide can be suppressed. As the reasons, the following are considered. The baking is conducted by two stages: first, coating and baking is repeated in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and then post-baking in a further high temperature of 520 degrees Celsius - 600 degrees Celsius. Compared with the baking at a high temperature from the beginning by the conventional method, crystallite diameter under the present invention will not enlarge beyond a certain degree. If the growth of crystallite diameter of iridium oxide is suppressed, the smaller the crystallite =
diameter is, the larger the effective surface area of the catalyst layer will be. Then, the oxygen generation overvoltage of the electrode can be decreased, oxygen generation is promoted, and the reaction to form Pb02 from lead ion can be suppressed. In this way, Pb02 attachment and covering on the electrode were suppressed.
Further, according to the present invention, simultaneously with increase in the effective surface area of catalyst layer, electric current is evenly distributed, that is, the concentration of electric current is suppressed, and consumption of the catalyst layer by electrolysis is reduced, which leads to improvement of electrode durability.
Furthermore, according to the present invention, improved quality of products and provision of special performance characteristics to products are achieved by controlling the amount of coating of iridium to 2g/m2 or more per time. When electrolysis is performed at a current density of 300A/dm2 - 700A/dm2 or more, or also an auxiliary anode is provided at a specified spot under a high load electrolysis conditions to give special performance characteristics to products obtained from electrolysis, load to the electrode catalyst layer can be lessened, electric current concentration can be prevented and consumption of electrode catalyst layer can be suppressed.
Brief Description of Drawings [Fig. 1] Fig. 1 is a graph indicating the change of degree of crystallinity of iridium oxide (1r02) of the catalyst layer by baking temperature and post-bake temperature.
[Fig. 2] Fig. 2 is a graph indicating the change of crystallite diameter of iridium oxide (Ir02) of the catalyst layer by baking temperature and post-bake temperature.
[Fig. 3] Fig. 3 is a graph indicating the change of the electrostatic capacity of the electrode by baking temperature and post-bake temperature.
[Fig. 4] Fig. 4 is a graph indicating the dependence of oxygen overvoltage on baking conditions.
Description of Embodiments The following explains embodiments of the present invention, in detail, in reference to the figures. In the present invention, it is found that if the effective surface area of the electrode catalyst layer is increased to suppress adhesive reaction of lead oxide to the electrode surface, oxygen generation overvoltage can be reduced and then, oxygen generation is promoted and at the same time the adhesive reaction of lead oxide can be suppressed. In addition, the present invention has been completed from the idea that it is necessary that iridium oxide of the catalyst layer is mainly crystalline in order to improve the electrode durability at the same time, and experiments were repeated.
In the present invention, a two-step baking is performed, first, in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius to form a catalyst layer containing amorphous Ir02 in the baking, then, in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to post-bake, through which the iridium oxide of the catalyst layer is almost completely crystallized.
Through the experiments conducted by inventors of the present invention, it has been proved that the catalyst layer containing amorphous iridium oxide, which can greatly increase the effective surface area, consumes amorphous iridium oxide quite rapidly by electrolysis and durability is reduced relatively. In other words, it is considered that the electrode durability cannot be improved unless iridium oxide of the catalyst layer is crystallized. Therefore, in order to achieve the purpose of the present invention that the effective surface area of the electrode catalyst layer is increased and the overvoltage of the electrode is reduced, the present invention applies two-step baking: high temperature baking plus high temperature post-baking in order to control the crystallite diameter of iridium oxide of the catalyst layer, through which iridium oxide crystal, smaller in size than the conventional product precipitates, resulting in increased effective surface area of the electrode catalyst layer and reduced overvoltage.
In the present invention, a catalyst layer containing amorphous iridium oxide is formed on the surface of the conductive metal substrate by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius;
thereafter, the catalyst layer of amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to crystallize the iridium oxide in the catalyst layer almost completely.
According to the present invention, improved quality of products and provision of special performance characteristics to products are achieved by controlling the amount of coating of iridium to 2g/m2 or more per time. When electrolysis is performed at a current density of 300A/dm2 - 700A/dm2 or more, or also an auxiliary anode is provided at a specified spot under a high load electrolysis conditions to give special performance characteristics to products obtained from electrolysis, load to the electrode catalyst layer can be lessened, electric current concentration can be prevented and consumption of electrode catalyst layer can be suppressed.
The baking temperature in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the post-baking temperature in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius are determined by the crystal particle size and the degree of crystallinity of iridium oxide to be formed in the catalyst layer, and the catalyst layer with a low oxygen overvoltage and a high corrosion resistance is formed in the above-mentioned temperature region.
In the present invention, the growth of the crystallite diameter of iridium oxide was able to be suppressed and the effective surface area of the catalyst layer was able to be increased by controlling the crystallite diameter of the iridium oxide in the electrode catalyst layer to a small number, preferably equal to or less than 9.0nm and most of the iridium oxide was crystallized, preferably, to the degree of crystallinity equal to or more than 80%.
Prior to forming the catalyst layer, if the AIP base layer containing tantalum and titanium components is provided on the conductive metal substrate, it is possible to prevent further interfacial corrosion of the metal substrate.
The base layer consisting of TiTa0x oxide layer may be applied instead of the AIP base layer.
The catalyst layer was formed in such a manner that hydrochloric acid aqueous solution of IrC13/Ta2C15 as a coating liquid was coated on the AIP coated titanium substrate at 3g-Ir/m2 per time and baked at a temperature by which part of Ir02 crystallizes (430 - 480 degrees Celsius). After repeating the coating and baking process until the necessary support amount of the catalyst was obtained, one hour post-bake was conducted at a further high temperature (520 degrees Celsius -degrees Celsius). In this way, the electrode sample was prepared. The prepared sample was measured for Ir02 crystalline of the catalyst layer by X-ray diffraction, oxygen generation overvoltage, electrostatic capacity of electrode, etc. and evaluated for sulfuric acid electrolysis and gelatin-added sulfuric acid electrolysis and lead adherence test.
As a result, it has been found that most of the Ir02 of the formed catalyst layer was crystalline, the crystallite diameter became smaller, and the electrode effective surface area increased. Accelerated life evaluation was carried out and found that, as to be described later, sulfuric acid electrolysis life was about 1.4 times that of the conventional product, and gelatin-added sulfuric acid electrolysis life was about 1.5 times that of the conventional product, proving improvement in durability.
The experimental conditions and methods by the present invention are as follows.
In order to investigate formation temperature of amorphous iridium oxide and the range of post-bake temperature for successive crystallization, a sample shown in Table 1 was manufactured and subjected to measurements of X-ray diffraction, cyclic voltammetry, oxygen overvoltage, etc.
The surface of titanium plate (JIS-I) was subjected to the dry blast with iron grit (G120 size), followed by pickling in an aqueous solution of concentrated hydrochloric acid for 10 minutes at the boiling point for cleaning treatment of the metal substrate of the electrode. The cleaned metal substrate of the electrode was set to the AIP unit applying Ti-Ta alloy target as a vapor source and a coating of tantalum and titanium alloy was applied as the base layer on the surface of the [Table 1]
Alloy disk comprising Ta:Ti=60wt%:40wt%
Target(vapor source) (back surface cooling) Vacuum pressure 1.5x10-2 Pa or less Metal substrate temperature 500 degrees Celsius or less Coating pressure 3.0x10-1-4.0x10-1Pa Vapor source charge power 20-30V, 140-160A
Coating time 15-20 minutes Coating thickness 2micuron(weight increase conversion) The coated metal substrate was heat-treated at 530 degrees Celsius in an Then, the coating solution prepared by dissolving iridium ,tetrachloride and tantalum pentachloride in concentrated hydrochloric acid was applied on the coated metal substrate. After drying, the thermal decomposition coating was conducted for 15 minutes in the electric furnace of air circulation type at a Then, the coated sample with catalyst layer was subjected to the post bake in the electric furnace of air circulation type for one hour at a temperature shown in Table 2 to manufacture an electrode for electrolysis. In addition, a sample not subjected to post-bake was manufactured for comparison purpose.
Baking temperature and post-bake temperature of each sample are shown in Table 2.
Experimental items for evaluation (1) Degree of crystallinity and measurement of crystallite diameter Ir02 crystallinity and crystallite diameter of the catalyst layer were measured by X-rays diffractometry.
The degree of crystallinity was estimated from the diffraction peak intensity.
(2) Electrostatic capacity of electrode Method: cyclic voltammetry Electrolyte : 150 g/L H2SO4 aq.
Electrolysis temperature : 60 degrees Celsius Electrolysis area : 10x10 mm2 Counter electrode : Zr plate (20 mmx70 mm) Reference electrode : Mercurous sulphate electrode (SSE) (3) Measurement of oxygen overvoltage Method: current interrupt method Electrolyte : 150 g/L H2SO4 aq.
Electrolysis temperature : 60 degrees Celsius Electrolysis area : 10x10 mm2 Counter electrode : Zr plate (20 mmx70 mm) Reference electrode : Mercurous sulphate electrode (SSE) [Table 2]
Oxygen Baking Post-bake Degree of Crystallite Electrostatic generation temperature temperature crystallinity diameter capacity Sample No. overvoltage (V vs. SSE
( C) ( C) (%) (nm) (C/m2) @100A/dm2) 1 none 0 0 88.8 0.851 2 520 100 7.7 21.6 0.963 3 560 100 7.8 15.4 0.987 4 600 100 7.7 11.6 1.021 none . 72 9.3 13.7 0.983 6 520 85 8.5 18.1 1.011 7 560 82 8.5 14.4 1.031 a 600 98 8.7 14.5 1.035 (Conventional 500-520 none 100 9.1 7.6 1.051 product) The changes of Ir02 crystal characteristics by the baking temperature and the post-bake temperature were as follows.
5 As for the estimation of degree of crystallinity, the intensity of the crystal diffraction peak (0=28 degrees) of each sample is expressed as a ratio when compared with the intensity of the crystal diffraction peak (0=28 degrees) of the conventional product which is assumed as 100. The results are given in Table 2.
In addition, Fig. 1 is a graph showing the degree of crystallinity based on the data in Table 2.
As is clear from Table 2 and Fig. 1, the degree of crystallinity of iridium oxide after post-bake of Samples 2-4 and Samples 6-8 of the example by the present invention, which had been subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius was 80%
or more. On the other hand, iridium oxide attributable to the electrode catalyst layer treated by the baking at 430 degrees Celsius without post-bake (Sample 1) did not show a clear peak, proving that the catalyst layer of this sample comprises amorphous iridium oxide. The degree of crystallinity of the electrode catalyst layer baked at 480 degrees Celsius without post-bake (Sample 5) was 72% with a lot of remaining amorphous iridium oxide. In addition, Sample 9, which is a conventional product was fully crystallized, showing the degree of crystallinity being 100%, but the crystallite diameter increases to 9.1nm, resulting in a low value of the electrostatic capacity of electrode at 7.6 with small effective surface area.
In other words, as the change of the degree of crystallinity by a high temperature post-bake, clear peak of Ir02 attributable to the electrode catalyst layer was observed after baking at 430 degrees Celsius and post-bake in a further high temperature, showing that amorphous Ir02 of the catalyst layer had changed to crystalline by a high temperature post-bake. In addition, it was found that the peak intensity was similar to that of the conventional product at any post-bake temperatures, showing that amorphous Ir02 did not remain. On the other hand, the products treated by the baking at 480 degrees Celsius showed a further high degree of crystallinity by a high temperature post-bake. However, it was found that a small amount of amorphous Ir02 still existed after post-bake at 520 degrees Celsius and 560 degrees Celsius. By contrast, the degree of crystallinity of Ir02 after the post-bake at 600 degrees Celsius was almost equivalent to the conventional product, showing full crystallization.
Then, the crystallite diameter was calculated from X-ray diffraction. The results are shown in Table 2. Fig. 2 was prepared based on the data in Table 2 relating to the crystallite diameter.
The crystal diameter of the amorphous Ir02 formed by the baking at 430 degrees Celsius without post-bake is indicated as "0". It was found that if post-bake is applied, amorphous Ir02 was crystallized, but the crystallite diameter of the formed crystal became smaller than that of the conventional product. In addition, there is little mutual dependence observed between the post-bake temperature and the crystallite diameter of Ir02.
On the other hand, the crystallite diameter of the baked product in 480 degrees Celsius followed by post-bake gave a smaller one than the conventional product, regardless of the post-bake temperature. In other words, crystallinity of Ir02 of the catalyst layer formed in a low temperature baking increased by post-bake, but the increasing of Ir02 crystallite diameter was able to be suppressed.
As is evident from the data on the crystallite diameter in Table 2 and Fig. 2, the crystallite diameter of iridium oxide after post-bake of Samples 2-4 and Samples 6-8 of the examples by the present invention, which was subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius -degrees Celsius was 9.0nm or less. On the other hand, iridium oxide attributable to the electrode catalyst layer treated by the baking at 430 degrees Celsius without post-bake (Sample 1) did not show a clear peak, proving that the catalyst layer of this sample comprises amorphous iridium oxide. The crystallite diameter of the electrode catalyst layer baked at 480 degrees Celsius without post-bake (Sample 5) was large to 9.3nm. The crystallite diameter of iridium oxide of Sample 9, which is the conventional product, was as large as 9.1nm.
Then, measurements were made about the change of effective surface area of the electrode catalyst layer prepared by high temperature baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius.
Electrostatic capacity of the electrode calculated by the cyclic voltammetry method is shown in Table 2. Electrostatic capacity of the electrode is proportional to the effective surface area of electrode, and it may be right to say that the higher the capacity, the higher the effective surface area also is. Fig. 3 shows the relationship between the electrostatic capacity and the baking conditions of the catalyst layer, based on the data in Table 2.
As is clear from Table 2 and Fig. 3, the electrostatic capacity of the electrode of Samples 2-4 and Samples 6-8 of the example by the present invention, which were subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius increased to a high point of 11.6 or more. On the other hand, 1102 of the catalyst layer formed by baking at 430 degrees Celsius without post-bake (Sample 1) showed the largest effective surface area (the electrolytic capacity of the electrode), since it is amorphous.
After conducting post-bake, the effective surface area (the electrolytic capacity of the electrode) decreased since Ir02 was crystallized, but it was still higher compared with the conventional product. This may be because the formed crystallite diameter was smaller than the conventional product. In addition, it was observed that the electrode effective surface area (the electrolytic capacity of the electrode) tended to decrease with the increasing of post-bake temperature.
Also, it has been found that if post-bake is conducted after the baking at 480 degrees Celsius (Samples 5-8), the effective surface areas (the electrolytic capacity of the electrode) are almost the same regardless of the post-bake temperature, meanwhile they doubled compared with the conventional product.
This is probably due to a smaller 1r02 crystallite diameter compared with the conventional product and also a small amount of amorphous 1r02 remaining.
Moreover, even if the post-bake temperature is increased, there was no change in the electrode effective surface area (the electrolytic capacity of the electrode).
The oxygen generation overvoltage (V vs. SSE @ 100A/dm2) of each sample was measured. The results are shown in Table 2. In addition, the dependence of the oxygen generation overvoltage on baking conditions is shown in Fig. 4. The trend of changing in the graph of Fig. 4 was reverse to that of Fig. 3. With increase of the electrode effective surface area, the oxygen generation overvoltage of the samples tended to decrease. As the reason, it is considered that increased electrode effective surface area contributed to dispersion of electric current distribution, lowering the actual electric current.
The product with the largest effective surface area baked at 430 degrees Celsius without post-bake showed the lowest oxygen overvoltage, but oxygen overvoltage increased as a result of decreased effective surface area by post-bake. Similar trend was observed with the product baked at 480 degrees Celsius in dependence of oxygen overvoltage on the post-bake temperature. In addition, the oxygen overvoltage of these samples was found to be higher than that of the conventional product. This seems to be because the surface area increased compared with the conventional product.
In Table 2 and Fig. 4, it is indicated oxygen overvoltage of Samples 2-4 and Samples 6-8 of the examples by the present invention, which were subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius decreased.
As mentioned above, the electrode manufactured by the baking means of baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius features to have a smaller Ir02 crystal of the catalyst layer compared with the conventional product and an increased electrode surface area. In these samples, electric current distribution can be dispersed under a high-load condition and actual electric current load was decreased, from which such effects as suppression of catalyst consumption and improvement in durability can be expected.
Examples The following describes examples by the present invention; provided, however, the present invention is not limited to these examples.
<Example 1>
The surface of titanium plate (JIS-I) was subjected to the dry blast with iron grit (G120 size), followed by pickling in an aqueous solution of concentrated hydrochloric acid for 10 minutes at the boiling point for cleaning treatment of the metal substrate of the electrode. The cleaned metal substrate of the electrode is set to the AIP unit applying Ti-Ta alloy target as a vapor source and a coating of tantalum and titanium alloy was applied as the AIP base layer on the surface of the metal substrate of the electrode. Coating condition is shown in Table 1.
The coated metal substrate was treated at 530 degrees Celsius in an electric furnace of air circulation type for 180 minutes.
Then, the coating solution prepared by dissolving iridium tetrachloride and tantalum pentachloride in concentrated hydrochloric acid is applied on the coated metal substrate. After drying, the thermolysis coating was conducted for 15 minutes in the electric furnace of air circulation type at 480 degrees Celsius to form an electrode catalyst layer comprising mixture oxides of iridium oxide and tantalum oxide. The amount of coating solution was determined so that the thickness of coating per time of the coating solution corresponds to approx. 3.0g/m2, as iridium metal. This coating-baking operation was repeated nine times to obtain the electrode catalyst layer of approx. 27.0g/m2, converted for metal iridium.
The X-ray diffraction was carried out for this sample. A clear peak of iridium oxide attributable to the electrode catalyst layer was observed, but the intensity of the peak was lower than that of Comparative Example 1, indicating that crystalline Ir02 had been partially precipitated.
Next, an electrode for electrolysis was manufactured in such a manner that the sample coated with the catalyst layer is post-baked in an electric furnace of air circulation type at 520 degrees Celsius for one hour.
The X-ray diffraction was carried out for the sample with post-baking. A clear peak of iridium oxide attributable to the electrode catalyst layer was observed, but the intensity of the peak was still lower than that of Comparative Example 1, though was higher than before the post-bake. From this, it has been known that the degree of crystallinity of the catalyst layer formed by the low temperature baking, before the post-bake, has increased, but amorphous Ir02 still remains partially.
About the electrode for electrolysis prepared in the above-mentioned manner, two types of life evaluation test were conducted for: Pure sulfuric acid solution and sulfuric acid solution with gelatin. Results are shown in Table 4. When compared with Comparative Example 1 (Conventional Product) in Table 4, the life for sulfuric acid electrolysis was 1.7 times and the life of gelatin-added sulfuric acid electrolysis was 1.1 times, identifying that durability to both sulfuric acid and organic additive has improved.
[Table 3]
Gelatin-added Sulfuric acid electrolysis sulfuric acid electrolysis Current density 500 A/dm2 300 A/dm2 150 g/L of H2SO4 aq. + 50 ppm Electrolyte 150 g/L of H2SO4 aq.
gelatin Electrolysis temperature 60 C
Counter electrode Zr plate Criterion of electrolysis At the time when a cell voltage increased 1.0 V
than an initial life cell voltage.
<Example 2>
The electrode for evaluation was manufactured in the same manner as with Example 1 except that post-bake was conducted in an electric furnace of air circulation type for one hour at 560 degrees Celsius and the same electrolysis evaluation was performed.
The X-ray diffraction performed after post-bake showed the degree of Ir02 crystallinity and crystallite diameter of the catalyst layer equivalent to Example 1.
As shown in Table 4, when compared with Comparative Example 1 (Conventional Product) in Table 4, the life of sulfuric acid electrolysis was 1.5 times and the life of gelatin-added sulfuric acid electrolysis was 1.3 times, identifying that durability to both sulfuric acid and organic additive has improved.
<Comparative Example 1>
The electrode catalyst layer comprising the mixture oxide of iridium oxide and tantalum oxide was formed as with Example 1, but changing the baking temperature in the electric furnace of circulation air type to 520 degrees Celsius and the baking time to fifteen minutes. The electrode thus manufactured without post-bake was evaluated for electrolysis by the X-ray diffraction as with Example 1.
The X-ray diffraction was performed on this sample, from which a clear peak of iridium oxide attributable to the electrode catalyst layer was observed, verifying that Ir02 in the catalyst layer is crystalline.
Life evaluation was made as with Example 1. From the results shown in Table 4, it has been made clear that the method of the low temperature baking plus high temperature post-bake, as suggested in the present invention, improves durability in electrolysis under high-load conditions.
<Comparative Example 2>
In the same manner as with Example 1 except that post-bake was carried out, the electrode for evaluation was manufactured and electrolysis evaluation was carried out in the same manner with Example 1.
As shown in Table 4, lives of the electrode baked at 480 degrees Celsius without post-bake for sulfuric acid electrolysis and gelatin-added sulfuric acid electrolysis were equivalent to that of the conventional product, proving no improvement in durability.
[Table 4]
Baking Post-bake Life of sulfuric Life of gelatin-added temperature temperature acid electrolysis sulfuric acid electrolysis ( C) ( C) (hr) (hr) Example Comparative 1 520 2508 978 Example 2 480 2604 1073 Industrial Applicability The present invention relates to an anode for oxygen generation used for various industrial electrolyses and a manufacturing method for the same; more in detail, it is applicable to a high-load durable anode for oxygen generation used for industrial electrolyses including manufacturing of electrolytic metal foils such as electrolytic copper foil, aluminum liquid contact, continuously electrogalvanized steel plate and metal extraction, having superior durability under high-load electrolysis conditions.
Solution to Problem As the first solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more, the coating is baked in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius to form the catalyst layer containing amorphous iridium oxide and the catalyst layer containing the amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius -600 degrees Celsius to crystallize almost all amount of iridium oxide in the catalyst layer.
As the second solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the degree of crystallinity of iridium oxide in the catalyst layer after the post-baking is made to be 80% or more.
As the third solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the crystallite diameter of iridium oxide in the catalyst layer is 9.0nm or less.
As the fourth solution to achieve the above-mentioned purposes, the present invention provides an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein a base layer containing tantalum and titanium ingredients is formed by the arc ion plating (hereafter called AIP) process on the conductive metal substrate before the formation of the catalyst layer.
As the fifth solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation, wherein the amount of coating of iridium per time for a catalyst layer is 2 g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to crystallize almost all amount of iridium oxide in the catalyst layer.
As the sixth solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation, wherein the amount of coating of iridium per time for a catalyst layer is 2g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to make the degree of crystallinity of iridium oxide in the catalyst layer to be 80% or more.
As the seventh solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation, wherein the amount of coating of iridium per time for a catalyst layer is 2g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to make the crystallite diameter of iridium oxide in the catalyst layer to be 9.0nm or less.
As the eighth solution to achieve the above-mentioned purposes, the present invention provides a manufacturing method for an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein an AIP base layer containing tantalum and titanium ingredients is formed by the AIP process on the conductive metal substrate before the formation of the catalyst layer.
Advantageous Effects of Invention In the formation for the electrode catalyst layer containing iridium oxide by the present invention, the amount of coating of iridium per time of the catalyst layer is 2g/m2 or more, baking is conducted, instead of the conventional repeated baking operations at 500 degrees Celsius or more, which are the perfect crystal deposition temperature, by two steps: baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius to form a catalyst layer containing amorphous iridium oxide and post-baking in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to suppress the crystallite diameter of iridium oxide in the electrode catalyst layer preferably to 9.0nm or less and to crystallize most of the iridium oxide preferably to 80% or more in crystallinity. Thus, the growth of crystallite diameter of iridium oxide was able to be suppressed and the effective surface area of the catalyst layer was able to be increased. Thus, according to the present invention, the growth of crystallite diameter of iridium oxide can be suppressed. As the reasons, the following are considered. The baking is conducted by two stages: first, coating and baking is repeated in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and then post-baking in a further high temperature of 520 degrees Celsius - 600 degrees Celsius. Compared with the baking at a high temperature from the beginning by the conventional method, crystallite diameter under the present invention will not enlarge beyond a certain degree. If the growth of crystallite diameter of iridium oxide is suppressed, the smaller the crystallite =
diameter is, the larger the effective surface area of the catalyst layer will be. Then, the oxygen generation overvoltage of the electrode can be decreased, oxygen generation is promoted, and the reaction to form Pb02 from lead ion can be suppressed. In this way, Pb02 attachment and covering on the electrode were suppressed.
Further, according to the present invention, simultaneously with increase in the effective surface area of catalyst layer, electric current is evenly distributed, that is, the concentration of electric current is suppressed, and consumption of the catalyst layer by electrolysis is reduced, which leads to improvement of electrode durability.
Furthermore, according to the present invention, improved quality of products and provision of special performance characteristics to products are achieved by controlling the amount of coating of iridium to 2g/m2 or more per time. When electrolysis is performed at a current density of 300A/dm2 - 700A/dm2 or more, or also an auxiliary anode is provided at a specified spot under a high load electrolysis conditions to give special performance characteristics to products obtained from electrolysis, load to the electrode catalyst layer can be lessened, electric current concentration can be prevented and consumption of electrode catalyst layer can be suppressed.
Brief Description of Drawings [Fig. 1] Fig. 1 is a graph indicating the change of degree of crystallinity of iridium oxide (1r02) of the catalyst layer by baking temperature and post-bake temperature.
[Fig. 2] Fig. 2 is a graph indicating the change of crystallite diameter of iridium oxide (Ir02) of the catalyst layer by baking temperature and post-bake temperature.
[Fig. 3] Fig. 3 is a graph indicating the change of the electrostatic capacity of the electrode by baking temperature and post-bake temperature.
[Fig. 4] Fig. 4 is a graph indicating the dependence of oxygen overvoltage on baking conditions.
Description of Embodiments The following explains embodiments of the present invention, in detail, in reference to the figures. In the present invention, it is found that if the effective surface area of the electrode catalyst layer is increased to suppress adhesive reaction of lead oxide to the electrode surface, oxygen generation overvoltage can be reduced and then, oxygen generation is promoted and at the same time the adhesive reaction of lead oxide can be suppressed. In addition, the present invention has been completed from the idea that it is necessary that iridium oxide of the catalyst layer is mainly crystalline in order to improve the electrode durability at the same time, and experiments were repeated.
In the present invention, a two-step baking is performed, first, in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius to form a catalyst layer containing amorphous Ir02 in the baking, then, in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to post-bake, through which the iridium oxide of the catalyst layer is almost completely crystallized.
Through the experiments conducted by inventors of the present invention, it has been proved that the catalyst layer containing amorphous iridium oxide, which can greatly increase the effective surface area, consumes amorphous iridium oxide quite rapidly by electrolysis and durability is reduced relatively. In other words, it is considered that the electrode durability cannot be improved unless iridium oxide of the catalyst layer is crystallized. Therefore, in order to achieve the purpose of the present invention that the effective surface area of the electrode catalyst layer is increased and the overvoltage of the electrode is reduced, the present invention applies two-step baking: high temperature baking plus high temperature post-baking in order to control the crystallite diameter of iridium oxide of the catalyst layer, through which iridium oxide crystal, smaller in size than the conventional product precipitates, resulting in increased effective surface area of the electrode catalyst layer and reduced overvoltage.
In the present invention, a catalyst layer containing amorphous iridium oxide is formed on the surface of the conductive metal substrate by baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius;
thereafter, the catalyst layer of amorphous iridium oxide is post-baked in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius to crystallize the iridium oxide in the catalyst layer almost completely.
According to the present invention, improved quality of products and provision of special performance characteristics to products are achieved by controlling the amount of coating of iridium to 2g/m2 or more per time. When electrolysis is performed at a current density of 300A/dm2 - 700A/dm2 or more, or also an auxiliary anode is provided at a specified spot under a high load electrolysis conditions to give special performance characteristics to products obtained from electrolysis, load to the electrode catalyst layer can be lessened, electric current concentration can be prevented and consumption of electrode catalyst layer can be suppressed.
The baking temperature in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius and the post-baking temperature in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius are determined by the crystal particle size and the degree of crystallinity of iridium oxide to be formed in the catalyst layer, and the catalyst layer with a low oxygen overvoltage and a high corrosion resistance is formed in the above-mentioned temperature region.
In the present invention, the growth of the crystallite diameter of iridium oxide was able to be suppressed and the effective surface area of the catalyst layer was able to be increased by controlling the crystallite diameter of the iridium oxide in the electrode catalyst layer to a small number, preferably equal to or less than 9.0nm and most of the iridium oxide was crystallized, preferably, to the degree of crystallinity equal to or more than 80%.
Prior to forming the catalyst layer, if the AIP base layer containing tantalum and titanium components is provided on the conductive metal substrate, it is possible to prevent further interfacial corrosion of the metal substrate.
The base layer consisting of TiTa0x oxide layer may be applied instead of the AIP base layer.
The catalyst layer was formed in such a manner that hydrochloric acid aqueous solution of IrC13/Ta2C15 as a coating liquid was coated on the AIP coated titanium substrate at 3g-Ir/m2 per time and baked at a temperature by which part of Ir02 crystallizes (430 - 480 degrees Celsius). After repeating the coating and baking process until the necessary support amount of the catalyst was obtained, one hour post-bake was conducted at a further high temperature (520 degrees Celsius -degrees Celsius). In this way, the electrode sample was prepared. The prepared sample was measured for Ir02 crystalline of the catalyst layer by X-ray diffraction, oxygen generation overvoltage, electrostatic capacity of electrode, etc. and evaluated for sulfuric acid electrolysis and gelatin-added sulfuric acid electrolysis and lead adherence test.
As a result, it has been found that most of the Ir02 of the formed catalyst layer was crystalline, the crystallite diameter became smaller, and the electrode effective surface area increased. Accelerated life evaluation was carried out and found that, as to be described later, sulfuric acid electrolysis life was about 1.4 times that of the conventional product, and gelatin-added sulfuric acid electrolysis life was about 1.5 times that of the conventional product, proving improvement in durability.
The experimental conditions and methods by the present invention are as follows.
In order to investigate formation temperature of amorphous iridium oxide and the range of post-bake temperature for successive crystallization, a sample shown in Table 1 was manufactured and subjected to measurements of X-ray diffraction, cyclic voltammetry, oxygen overvoltage, etc.
The surface of titanium plate (JIS-I) was subjected to the dry blast with iron grit (G120 size), followed by pickling in an aqueous solution of concentrated hydrochloric acid for 10 minutes at the boiling point for cleaning treatment of the metal substrate of the electrode. The cleaned metal substrate of the electrode was set to the AIP unit applying Ti-Ta alloy target as a vapor source and a coating of tantalum and titanium alloy was applied as the base layer on the surface of the [Table 1]
Alloy disk comprising Ta:Ti=60wt%:40wt%
Target(vapor source) (back surface cooling) Vacuum pressure 1.5x10-2 Pa or less Metal substrate temperature 500 degrees Celsius or less Coating pressure 3.0x10-1-4.0x10-1Pa Vapor source charge power 20-30V, 140-160A
Coating time 15-20 minutes Coating thickness 2micuron(weight increase conversion) The coated metal substrate was heat-treated at 530 degrees Celsius in an Then, the coating solution prepared by dissolving iridium ,tetrachloride and tantalum pentachloride in concentrated hydrochloric acid was applied on the coated metal substrate. After drying, the thermal decomposition coating was conducted for 15 minutes in the electric furnace of air circulation type at a Then, the coated sample with catalyst layer was subjected to the post bake in the electric furnace of air circulation type for one hour at a temperature shown in Table 2 to manufacture an electrode for electrolysis. In addition, a sample not subjected to post-bake was manufactured for comparison purpose.
Baking temperature and post-bake temperature of each sample are shown in Table 2.
Experimental items for evaluation (1) Degree of crystallinity and measurement of crystallite diameter Ir02 crystallinity and crystallite diameter of the catalyst layer were measured by X-rays diffractometry.
The degree of crystallinity was estimated from the diffraction peak intensity.
(2) Electrostatic capacity of electrode Method: cyclic voltammetry Electrolyte : 150 g/L H2SO4 aq.
Electrolysis temperature : 60 degrees Celsius Electrolysis area : 10x10 mm2 Counter electrode : Zr plate (20 mmx70 mm) Reference electrode : Mercurous sulphate electrode (SSE) (3) Measurement of oxygen overvoltage Method: current interrupt method Electrolyte : 150 g/L H2SO4 aq.
Electrolysis temperature : 60 degrees Celsius Electrolysis area : 10x10 mm2 Counter electrode : Zr plate (20 mmx70 mm) Reference electrode : Mercurous sulphate electrode (SSE) [Table 2]
Oxygen Baking Post-bake Degree of Crystallite Electrostatic generation temperature temperature crystallinity diameter capacity Sample No. overvoltage (V vs. SSE
( C) ( C) (%) (nm) (C/m2) @100A/dm2) 1 none 0 0 88.8 0.851 2 520 100 7.7 21.6 0.963 3 560 100 7.8 15.4 0.987 4 600 100 7.7 11.6 1.021 none . 72 9.3 13.7 0.983 6 520 85 8.5 18.1 1.011 7 560 82 8.5 14.4 1.031 a 600 98 8.7 14.5 1.035 (Conventional 500-520 none 100 9.1 7.6 1.051 product) The changes of Ir02 crystal characteristics by the baking temperature and the post-bake temperature were as follows.
5 As for the estimation of degree of crystallinity, the intensity of the crystal diffraction peak (0=28 degrees) of each sample is expressed as a ratio when compared with the intensity of the crystal diffraction peak (0=28 degrees) of the conventional product which is assumed as 100. The results are given in Table 2.
In addition, Fig. 1 is a graph showing the degree of crystallinity based on the data in Table 2.
As is clear from Table 2 and Fig. 1, the degree of crystallinity of iridium oxide after post-bake of Samples 2-4 and Samples 6-8 of the example by the present invention, which had been subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius was 80%
or more. On the other hand, iridium oxide attributable to the electrode catalyst layer treated by the baking at 430 degrees Celsius without post-bake (Sample 1) did not show a clear peak, proving that the catalyst layer of this sample comprises amorphous iridium oxide. The degree of crystallinity of the electrode catalyst layer baked at 480 degrees Celsius without post-bake (Sample 5) was 72% with a lot of remaining amorphous iridium oxide. In addition, Sample 9, which is a conventional product was fully crystallized, showing the degree of crystallinity being 100%, but the crystallite diameter increases to 9.1nm, resulting in a low value of the electrostatic capacity of electrode at 7.6 with small effective surface area.
In other words, as the change of the degree of crystallinity by a high temperature post-bake, clear peak of Ir02 attributable to the electrode catalyst layer was observed after baking at 430 degrees Celsius and post-bake in a further high temperature, showing that amorphous Ir02 of the catalyst layer had changed to crystalline by a high temperature post-bake. In addition, it was found that the peak intensity was similar to that of the conventional product at any post-bake temperatures, showing that amorphous Ir02 did not remain. On the other hand, the products treated by the baking at 480 degrees Celsius showed a further high degree of crystallinity by a high temperature post-bake. However, it was found that a small amount of amorphous Ir02 still existed after post-bake at 520 degrees Celsius and 560 degrees Celsius. By contrast, the degree of crystallinity of Ir02 after the post-bake at 600 degrees Celsius was almost equivalent to the conventional product, showing full crystallization.
Then, the crystallite diameter was calculated from X-ray diffraction. The results are shown in Table 2. Fig. 2 was prepared based on the data in Table 2 relating to the crystallite diameter.
The crystal diameter of the amorphous Ir02 formed by the baking at 430 degrees Celsius without post-bake is indicated as "0". It was found that if post-bake is applied, amorphous Ir02 was crystallized, but the crystallite diameter of the formed crystal became smaller than that of the conventional product. In addition, there is little mutual dependence observed between the post-bake temperature and the crystallite diameter of Ir02.
On the other hand, the crystallite diameter of the baked product in 480 degrees Celsius followed by post-bake gave a smaller one than the conventional product, regardless of the post-bake temperature. In other words, crystallinity of Ir02 of the catalyst layer formed in a low temperature baking increased by post-bake, but the increasing of Ir02 crystallite diameter was able to be suppressed.
As is evident from the data on the crystallite diameter in Table 2 and Fig. 2, the crystallite diameter of iridium oxide after post-bake of Samples 2-4 and Samples 6-8 of the examples by the present invention, which was subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius -degrees Celsius was 9.0nm or less. On the other hand, iridium oxide attributable to the electrode catalyst layer treated by the baking at 430 degrees Celsius without post-bake (Sample 1) did not show a clear peak, proving that the catalyst layer of this sample comprises amorphous iridium oxide. The crystallite diameter of the electrode catalyst layer baked at 480 degrees Celsius without post-bake (Sample 5) was large to 9.3nm. The crystallite diameter of iridium oxide of Sample 9, which is the conventional product, was as large as 9.1nm.
Then, measurements were made about the change of effective surface area of the electrode catalyst layer prepared by high temperature baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius.
Electrostatic capacity of the electrode calculated by the cyclic voltammetry method is shown in Table 2. Electrostatic capacity of the electrode is proportional to the effective surface area of electrode, and it may be right to say that the higher the capacity, the higher the effective surface area also is. Fig. 3 shows the relationship between the electrostatic capacity and the baking conditions of the catalyst layer, based on the data in Table 2.
As is clear from Table 2 and Fig. 3, the electrostatic capacity of the electrode of Samples 2-4 and Samples 6-8 of the example by the present invention, which were subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius increased to a high point of 11.6 or more. On the other hand, 1102 of the catalyst layer formed by baking at 430 degrees Celsius without post-bake (Sample 1) showed the largest effective surface area (the electrolytic capacity of the electrode), since it is amorphous.
After conducting post-bake, the effective surface area (the electrolytic capacity of the electrode) decreased since Ir02 was crystallized, but it was still higher compared with the conventional product. This may be because the formed crystallite diameter was smaller than the conventional product. In addition, it was observed that the electrode effective surface area (the electrolytic capacity of the electrode) tended to decrease with the increasing of post-bake temperature.
Also, it has been found that if post-bake is conducted after the baking at 480 degrees Celsius (Samples 5-8), the effective surface areas (the electrolytic capacity of the electrode) are almost the same regardless of the post-bake temperature, meanwhile they doubled compared with the conventional product.
This is probably due to a smaller 1r02 crystallite diameter compared with the conventional product and also a small amount of amorphous 1r02 remaining.
Moreover, even if the post-bake temperature is increased, there was no change in the electrode effective surface area (the electrolytic capacity of the electrode).
The oxygen generation overvoltage (V vs. SSE @ 100A/dm2) of each sample was measured. The results are shown in Table 2. In addition, the dependence of the oxygen generation overvoltage on baking conditions is shown in Fig. 4. The trend of changing in the graph of Fig. 4 was reverse to that of Fig. 3. With increase of the electrode effective surface area, the oxygen generation overvoltage of the samples tended to decrease. As the reason, it is considered that increased electrode effective surface area contributed to dispersion of electric current distribution, lowering the actual electric current.
The product with the largest effective surface area baked at 430 degrees Celsius without post-bake showed the lowest oxygen overvoltage, but oxygen overvoltage increased as a result of decreased effective surface area by post-bake. Similar trend was observed with the product baked at 480 degrees Celsius in dependence of oxygen overvoltage on the post-bake temperature. In addition, the oxygen overvoltage of these samples was found to be higher than that of the conventional product. This seems to be because the surface area increased compared with the conventional product.
In Table 2 and Fig. 4, it is indicated oxygen overvoltage of Samples 2-4 and Samples 6-8 of the examples by the present invention, which were subjected to baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius decreased.
As mentioned above, the electrode manufactured by the baking means of baking in a relatively high temperature region of 430 degrees Celsius - 480 degrees Celsius plus post-bake in a further high temperature region of 520 degrees Celsius - 600 degrees Celsius features to have a smaller Ir02 crystal of the catalyst layer compared with the conventional product and an increased electrode surface area. In these samples, electric current distribution can be dispersed under a high-load condition and actual electric current load was decreased, from which such effects as suppression of catalyst consumption and improvement in durability can be expected.
Examples The following describes examples by the present invention; provided, however, the present invention is not limited to these examples.
<Example 1>
The surface of titanium plate (JIS-I) was subjected to the dry blast with iron grit (G120 size), followed by pickling in an aqueous solution of concentrated hydrochloric acid for 10 minutes at the boiling point for cleaning treatment of the metal substrate of the electrode. The cleaned metal substrate of the electrode is set to the AIP unit applying Ti-Ta alloy target as a vapor source and a coating of tantalum and titanium alloy was applied as the AIP base layer on the surface of the metal substrate of the electrode. Coating condition is shown in Table 1.
The coated metal substrate was treated at 530 degrees Celsius in an electric furnace of air circulation type for 180 minutes.
Then, the coating solution prepared by dissolving iridium tetrachloride and tantalum pentachloride in concentrated hydrochloric acid is applied on the coated metal substrate. After drying, the thermolysis coating was conducted for 15 minutes in the electric furnace of air circulation type at 480 degrees Celsius to form an electrode catalyst layer comprising mixture oxides of iridium oxide and tantalum oxide. The amount of coating solution was determined so that the thickness of coating per time of the coating solution corresponds to approx. 3.0g/m2, as iridium metal. This coating-baking operation was repeated nine times to obtain the electrode catalyst layer of approx. 27.0g/m2, converted for metal iridium.
The X-ray diffraction was carried out for this sample. A clear peak of iridium oxide attributable to the electrode catalyst layer was observed, but the intensity of the peak was lower than that of Comparative Example 1, indicating that crystalline Ir02 had been partially precipitated.
Next, an electrode for electrolysis was manufactured in such a manner that the sample coated with the catalyst layer is post-baked in an electric furnace of air circulation type at 520 degrees Celsius for one hour.
The X-ray diffraction was carried out for the sample with post-baking. A clear peak of iridium oxide attributable to the electrode catalyst layer was observed, but the intensity of the peak was still lower than that of Comparative Example 1, though was higher than before the post-bake. From this, it has been known that the degree of crystallinity of the catalyst layer formed by the low temperature baking, before the post-bake, has increased, but amorphous Ir02 still remains partially.
About the electrode for electrolysis prepared in the above-mentioned manner, two types of life evaluation test were conducted for: Pure sulfuric acid solution and sulfuric acid solution with gelatin. Results are shown in Table 4. When compared with Comparative Example 1 (Conventional Product) in Table 4, the life for sulfuric acid electrolysis was 1.7 times and the life of gelatin-added sulfuric acid electrolysis was 1.1 times, identifying that durability to both sulfuric acid and organic additive has improved.
[Table 3]
Gelatin-added Sulfuric acid electrolysis sulfuric acid electrolysis Current density 500 A/dm2 300 A/dm2 150 g/L of H2SO4 aq. + 50 ppm Electrolyte 150 g/L of H2SO4 aq.
gelatin Electrolysis temperature 60 C
Counter electrode Zr plate Criterion of electrolysis At the time when a cell voltage increased 1.0 V
than an initial life cell voltage.
<Example 2>
The electrode for evaluation was manufactured in the same manner as with Example 1 except that post-bake was conducted in an electric furnace of air circulation type for one hour at 560 degrees Celsius and the same electrolysis evaluation was performed.
The X-ray diffraction performed after post-bake showed the degree of Ir02 crystallinity and crystallite diameter of the catalyst layer equivalent to Example 1.
As shown in Table 4, when compared with Comparative Example 1 (Conventional Product) in Table 4, the life of sulfuric acid electrolysis was 1.5 times and the life of gelatin-added sulfuric acid electrolysis was 1.3 times, identifying that durability to both sulfuric acid and organic additive has improved.
<Comparative Example 1>
The electrode catalyst layer comprising the mixture oxide of iridium oxide and tantalum oxide was formed as with Example 1, but changing the baking temperature in the electric furnace of circulation air type to 520 degrees Celsius and the baking time to fifteen minutes. The electrode thus manufactured without post-bake was evaluated for electrolysis by the X-ray diffraction as with Example 1.
The X-ray diffraction was performed on this sample, from which a clear peak of iridium oxide attributable to the electrode catalyst layer was observed, verifying that Ir02 in the catalyst layer is crystalline.
Life evaluation was made as with Example 1. From the results shown in Table 4, it has been made clear that the method of the low temperature baking plus high temperature post-bake, as suggested in the present invention, improves durability in electrolysis under high-load conditions.
<Comparative Example 2>
In the same manner as with Example 1 except that post-bake was carried out, the electrode for evaluation was manufactured and electrolysis evaluation was carried out in the same manner with Example 1.
As shown in Table 4, lives of the electrode baked at 480 degrees Celsius without post-bake for sulfuric acid electrolysis and gelatin-added sulfuric acid electrolysis were equivalent to that of the conventional product, proving no improvement in durability.
[Table 4]
Baking Post-bake Life of sulfuric Life of gelatin-added temperature temperature acid electrolysis sulfuric acid electrolysis ( C) ( C) (hr) (hr) Example Comparative 1 520 2508 978 Example 2 480 2604 1073 Industrial Applicability The present invention relates to an anode for oxygen generation used for various industrial electrolyses and a manufacturing method for the same; more in detail, it is applicable to a high-load durable anode for oxygen generation used for industrial electrolyses including manufacturing of electrolytic metal foils such as electrolytic copper foil, aluminum liquid contact, continuously electrogalvanized steel plate and metal extraction, having superior durability under high-load electrolysis conditions.
Claims (8)
- [Claim 1]
An anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more, the coating is baked in a high temperature region of 430 degrees Celsius -480 degrees Celsius to form the catalyst layer containing amorphous iridium oxide and the catalyst layer containing the amorphous iridium oxide is post-baked in a high temperature region of 520 degrees Celsius - 600 degrees Celsius to crystallize almost all amount of iridium oxide in the catalyst layer. - [Claim 2]
The anode for oxygen generation as in Claim 1, comprising the conductive metal substrate and the catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the degree of crystallinity of iridium oxide in the catalyst layer after the post-bake is made to be 80% or more. - [Claim 3]
The anode for oxygen generation, as in Claim 1 or 2, comprising the conductive metal substrate and the catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the crystallite diameter of iridium oxide in the catalyst layer is made to be 9.0nm or less. - [Claim 4]
The anode for oxygen generation, as in any one of Claims 1-3, comprising the conductive metal substrate and the catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein an arc ion plating base layer containing tantalum and titanium ingredients is formed by the arc ion plating process on the conductive metal substrate before the formation of the catalyst layer. - [Claim 5]
A manufacturing method for an anode for oxygen generation comprising a conductive metal substrate and a catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed on the surface of the conductive metal substrate by baking in a high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a high temperature region of 520 degrees Celsius - 600 degrees Celsius to crystallize almost all amount of iridium oxide in the catalyst layer. - [Claim 6]
The manufacturing method for the anode for oxygen generation, as in Claim 5, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed on the surface of the conductive metal substrate by baking in a high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a high temperature region of 520 degrees Celsius - 600 degrees Celsius to make the degree of crystallinity of iridium oxide in the catalyst layer to be 80% or more. - [Claim 7]
The manufacturing method for the anode for oxygen generation, as in Claim 5 or 6, wherein the amount of coating of iridium per time for the catalyst layer is 2g/m2 or more and the catalyst layer containing amorphous iridium oxide is formed on the surface of the conductive metal substrate by baking in a high temperature region of 430 degrees Celsius - 480 degrees Celsius and the catalyst layer containing amorphous iridium oxide is post-baked in a high temperature region of 520 degrees Celsius - 600 degrees Celsius to make crystallite diameter of iridium oxide in the catalyst layer to be 9.0nm or less. - [Claim 8]
The manufacturing method for the anode for oxygen generation, as in any one of Claims 5-7, comprising the conductive metal substrate and the catalyst layer containing iridium oxide formed on the conductive metal substrate, wherein the arc ion plating base layer containing tantalum and titanium ingredients is formed by the arc ion plating process on the conductive metal substrate before the formation of the catalyst layer.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2011283846 | 2011-12-26 | ||
| JP2011-283846 | 2011-12-26 | ||
| PCT/JP2012/083168 WO2013099780A2 (en) | 2011-12-26 | 2012-12-14 | High-load durable anode for oxygen generation and manufacturing method for the same |
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| Publication Number | Publication Date |
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| CA2859939A1 true CA2859939A1 (en) | 2013-07-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2859939A Abandoned CA2859939A1 (en) | 2011-12-26 | 2012-12-14 | High-load durable anode for oxygen generation and manufacturing method for the same |
Country Status (14)
| Country | Link |
|---|---|
| US (1) | US20150075978A1 (en) |
| JP (1) | JP5686455B2 (en) |
| KR (1) | KR101583179B1 (en) |
| CN (1) | CN104024481A (en) |
| AU (1) | AU2012361801A1 (en) |
| CA (1) | CA2859939A1 (en) |
| CL (1) | CL2014001717A1 (en) |
| MX (1) | MX2014007759A (en) |
| MY (1) | MY162043A (en) |
| PE (1) | PE20142157A1 (en) |
| PH (1) | PH12014501345B1 (en) |
| TW (1) | TWI541385B (en) |
| WO (1) | WO2013099780A2 (en) |
| ZA (1) | ZA201404259B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6498305B2 (en) * | 2015-09-18 | 2019-04-10 | 旭化成株式会社 | Anode for water electrolysis, electrolysis cell, and method for producing anode for water electrolysis |
| JP2017115232A (en) * | 2015-12-25 | 2017-06-29 | 株式会社東芝 | Electrode, membrane electrode composite, electrochemical cell and stack |
| RU2720309C1 (en) * | 2016-11-22 | 2020-04-28 | Асахи Касеи Кабусики Кайся | Electrode for electrolysis |
| KR102126183B1 (en) * | 2017-11-29 | 2020-06-24 | 한국과학기술연구원 | Diffusion layer and oxygen electrode composite layers of polymer electrolyte membrane water electrolysis apparatus and method for preparing the same and polymer electrolyte membrane water electrolysis apparatus using the same |
| US11965255B2 (en) * | 2018-06-12 | 2024-04-23 | Japan Science And Technology Agency | Catalyst and method of use thereof |
| CN110760894A (en) * | 2019-10-28 | 2020-02-07 | 昆明冶金研究院 | Preparation method of titanium coating anode |
| EP4474530A1 (en) * | 2022-03-31 | 2024-12-11 | De Nora Permelec Ltd | Electrolysis electrode and method for producing same |
Family Cites Families (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56116892A (en) * | 1980-02-20 | 1981-09-12 | Japan Carlit Co Ltd:The | Insoluble anode for generating oxygen and preparation thereof |
| DE3731285A1 (en) * | 1987-09-17 | 1989-04-06 | Conradty Metallelek | Dimensionally stable anode, method for manufacturing it, and use thereof |
| JPH0499294A (en) * | 1990-08-09 | 1992-03-31 | Daiso Co Ltd | Oxygen generating anode and its production |
| NL9101753A (en) * | 1991-10-21 | 1993-05-17 | Magneto Chemie Bv | ANODES WITH EXTENDED LIFE AND METHODS FOR THEIR MANUFACTURE. |
| US5587058A (en) * | 1995-09-21 | 1996-12-24 | Karpov Institute Of Physical Chemicstry | Electrode and method of preparation thereof |
| US7247229B2 (en) * | 1999-06-28 | 2007-07-24 | Eltech Systems Corporation | Coatings for the inhibition of undesirable oxidation in an electrochemical cell |
| US6527939B1 (en) * | 1999-06-28 | 2003-03-04 | Eltech Systems Corporation | Method of producing copper foil with an anode having multiple coating layers |
| JP3654204B2 (en) | 2001-03-15 | 2005-06-02 | ダイソー株式会社 | Oxygen generating anode |
| JP3914162B2 (en) | 2003-02-07 | 2007-05-16 | ダイソー株式会社 | Oxygen generating electrode |
| US7258778B2 (en) * | 2003-03-24 | 2007-08-21 | Eltech Systems Corporation | Electrocatalytic coating with lower platinum group metals and electrode made therefrom |
| MX2007002355A (en) * | 2004-09-01 | 2007-05-11 | Eltech Systems Corp | Pd-containing coating for low chlorine overvoltage. |
| JP4771130B2 (en) | 2005-11-25 | 2011-09-14 | ダイソー株式会社 | Oxygen generating electrode |
| CN1995464A (en) * | 2006-11-28 | 2007-07-11 | 北京科技大学 | Nanocrystalline iridium series oxide coating electrode preparation method |
| TWI453306B (en) * | 2008-03-31 | 2014-09-21 | Permelec Electrode Ltd | Method for manufacturing electrode for electrolysis |
| JP4516617B2 (en) * | 2008-06-09 | 2010-08-04 | 学校法人同志社 | Anode for electrowinning zinc and electrowinning method |
| JP4516618B2 (en) | 2008-06-23 | 2010-08-04 | 学校法人同志社 | Anode for electrolytic collection of cobalt and electrolytic collection method |
| JP5681343B2 (en) * | 2008-09-01 | 2015-03-04 | 旭化成ケミカルズ株式会社 | Electrode for electrolysis |
| US20120279853A1 (en) * | 2009-12-25 | 2012-11-08 | Asahi Kasei Chemicals Corporation | Cathode, electrolytic cell for electrolysis of alkali metal chloride, and method for producing negative electrode |
| CN101914782A (en) * | 2010-07-27 | 2010-12-15 | 武汉大学 | Metal oxide anode suitable for electric Fenton system and preparation method thereof |
| CN102168283B (en) * | 2011-04-08 | 2014-01-15 | 江苏美特林科特殊合金有限公司 | Electrode coating and preparation method thereof |
-
2012
- 2012-12-14 KR KR1020147019024A patent/KR101583179B1/en not_active Expired - Fee Related
- 2012-12-14 PE PE2014001028A patent/PE20142157A1/en not_active Application Discontinuation
- 2012-12-14 JP JP2014512990A patent/JP5686455B2/en not_active Expired - Fee Related
- 2012-12-14 WO PCT/JP2012/083168 patent/WO2013099780A2/en active Application Filing
- 2012-12-14 CA CA2859939A patent/CA2859939A1/en not_active Abandoned
- 2012-12-14 AU AU2012361801A patent/AU2012361801A1/en not_active Abandoned
- 2012-12-14 MX MX2014007759A patent/MX2014007759A/en unknown
- 2012-12-14 US US14/367,309 patent/US20150075978A1/en not_active Abandoned
- 2012-12-14 CN CN201280064839.0A patent/CN104024481A/en active Pending
- 2012-12-14 MY MYPI2014701496A patent/MY162043A/en unknown
- 2012-12-26 TW TW101150074A patent/TWI541385B/en not_active IP Right Cessation
-
2014
- 2014-06-10 ZA ZA2014/04259A patent/ZA201404259B/en unknown
- 2014-06-13 PH PH12014501345A patent/PH12014501345B1/en unknown
- 2014-06-24 CL CL2014001717A patent/CL2014001717A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| MX2014007759A (en) | 2015-04-14 |
| TW201339372A (en) | 2013-10-01 |
| PH12014501345A1 (en) | 2014-09-15 |
| PH12014501345B1 (en) | 2018-07-13 |
| WO2013099780A2 (en) | 2013-07-04 |
| KR20140101425A (en) | 2014-08-19 |
| JP5686455B2 (en) | 2015-03-18 |
| JP2014530292A (en) | 2014-11-17 |
| MY162043A (en) | 2017-05-31 |
| WO2013099780A3 (en) | 2013-10-10 |
| US20150075978A1 (en) | 2015-03-19 |
| TWI541385B (en) | 2016-07-11 |
| CL2014001717A1 (en) | 2014-09-05 |
| KR101583179B1 (en) | 2016-01-07 |
| CN104024481A (en) | 2014-09-03 |
| ZA201404259B (en) | 2015-09-30 |
| PE20142157A1 (en) | 2015-01-17 |
| AU2012361801A1 (en) | 2014-06-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |
Effective date: 20161214 |