WO2022264960A1 - イリジウム-マンガン酸化物複合材料、イリジウム-マンガン酸化物複合電極材料、及びこれらの製造方法 - Google Patents
イリジウム-マンガン酸化物複合材料、イリジウム-マンガン酸化物複合電極材料、及びこれらの製造方法 Download PDFInfo
- Publication number
- WO2022264960A1 WO2022264960A1 PCT/JP2022/023599 JP2022023599W WO2022264960A1 WO 2022264960 A1 WO2022264960 A1 WO 2022264960A1 JP 2022023599 W JP2022023599 W JP 2022023599W WO 2022264960 A1 WO2022264960 A1 WO 2022264960A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- iridium
- manganese oxide
- oxide composite
- manganese
- composite material
- Prior art date
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 202
- ZWWLICUSXWKZBB-UHFFFAOYSA-N iridium(3+) manganese(2+) oxygen(2-) Chemical compound [O-2].[Mn+2].[Ir+3] ZWWLICUSXWKZBB-UHFFFAOYSA-N 0.000 title claims abstract description 198
- 239000007772 electrode material Substances 0.000 title claims abstract description 88
- 238000000034 method Methods 0.000 title claims abstract description 14
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 claims abstract description 174
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 94
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims abstract description 92
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 70
- 239000001301 oxygen Substances 0.000 claims abstract description 68
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 65
- 238000005868 electrolysis reaction Methods 0.000 claims abstract description 56
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000000463 material Substances 0.000 claims abstract description 34
- 239000000835 fiber Substances 0.000 claims abstract description 20
- 239000000758 substrate Substances 0.000 claims description 59
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 50
- 229910052751 metal Inorganic materials 0.000 claims description 38
- 239000002184 metal Substances 0.000 claims description 37
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 35
- 239000011572 manganese Substances 0.000 claims description 34
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 33
- 150000002503 iridium Chemical class 0.000 claims description 33
- 238000004519 manufacturing process Methods 0.000 claims description 32
- 229910052748 manganese Inorganic materials 0.000 claims description 31
- 239000011259 mixed solution Substances 0.000 claims description 29
- 238000005259 measurement Methods 0.000 claims description 28
- 239000012266 salt solution Substances 0.000 claims description 27
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 26
- 239000010936 titanium Substances 0.000 claims description 25
- 238000000137 annealing Methods 0.000 claims description 23
- 229910052719 titanium Inorganic materials 0.000 claims description 23
- 229910052697 platinum Inorganic materials 0.000 claims description 17
- 238000001228 spectrum Methods 0.000 claims description 17
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 claims description 16
- 239000012528 membrane Substances 0.000 claims description 15
- 238000000833 X-ray absorption fine structure spectroscopy Methods 0.000 claims description 14
- GZMKWMMWAHQTHD-UHFFFAOYSA-L [Mn++].OS([O-])(=O)=O.OS([O-])(=O)=O Chemical compound [Mn++].OS([O-])(=O)=O.OS([O-])(=O)=O GZMKWMMWAHQTHD-UHFFFAOYSA-L 0.000 claims description 14
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 13
- 238000004998 X ray absorption near edge structure spectroscopy Methods 0.000 claims description 12
- 238000010521 absorption reaction Methods 0.000 claims description 12
- 239000001257 hydrogen Substances 0.000 claims description 12
- 229910052739 hydrogen Inorganic materials 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 11
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- 239000013078 crystal Substances 0.000 claims description 10
- 238000007654 immersion Methods 0.000 claims description 9
- 239000005518 polymer electrolyte Substances 0.000 claims description 9
- SHMWNGFNWYELHA-UHFFFAOYSA-N iridium manganese Chemical compound [Mn].[Ir] SHMWNGFNWYELHA-UHFFFAOYSA-N 0.000 claims description 3
- 239000003054 catalyst Substances 0.000 abstract description 57
- 230000003197 catalytic effect Effects 0.000 abstract description 12
- 229940099596 manganese sulfate Drugs 0.000 description 21
- 235000007079 manganese sulphate Nutrition 0.000 description 21
- 239000011702 manganese sulphate Substances 0.000 description 21
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 21
- 238000000151 deposition Methods 0.000 description 13
- 230000000694 effects Effects 0.000 description 13
- 239000011248 coating agent Substances 0.000 description 12
- 238000000576 coating method Methods 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000011156 evaluation Methods 0.000 description 10
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 230000002378 acidificating effect Effects 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000004070 electrodeposition Methods 0.000 description 6
- 239000010410 layer Substances 0.000 description 6
- 238000003786 synthesis reaction Methods 0.000 description 6
- 230000008021 deposition Effects 0.000 description 5
- 238000002848 electrochemical method Methods 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
- -1 platinum group metals Chemical class 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 239000001569 carbon dioxide Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 239000008235 industrial water Substances 0.000 description 4
- 230000003993 interaction Effects 0.000 description 4
- 229910001437 manganese ion Inorganic materials 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 229910052723 transition metal Inorganic materials 0.000 description 4
- 150000003624 transition metals Chemical class 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 238000010828 elution Methods 0.000 description 3
- 229910000457 iridium oxide Inorganic materials 0.000 description 3
- 150000002926 oxygen Chemical class 0.000 description 3
- 230000000704 physical effect Effects 0.000 description 3
- 229910052700 potassium Inorganic materials 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- 239000011163 secondary particle Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 229920000557 Nafion® Polymers 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 150000001450 anions Chemical class 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000010411 electrocatalyst Substances 0.000 description 2
- 239000002659 electrodeposit Substances 0.000 description 2
- 239000008151 electrolyte solution Substances 0.000 description 2
- 238000000921 elemental analysis Methods 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- PPNAOCWZXJOHFK-UHFFFAOYSA-N manganese(2+);oxygen(2-) Chemical class [O-2].[Mn+2] PPNAOCWZXJOHFK-UHFFFAOYSA-N 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229910000510 noble metal Inorganic materials 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000000550 scanning electron microscopy energy dispersive X-ray spectroscopy Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000001075 voltammogram Methods 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 230000004931 aggregating effect Effects 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 238000005341 cation exchange Methods 0.000 description 1
- 239000011247 coating layer Substances 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
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000000192 extended X-ray absorption fine structure spectroscopy Methods 0.000 description 1
- 238000002795 fluorescence method Methods 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- QOSATHPSBFQAML-UHFFFAOYSA-N hydrogen peroxide;hydrate Chemical compound O.OO QOSATHPSBFQAML-UHFFFAOYSA-N 0.000 description 1
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000011859 microparticle Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 235000006408 oxalic acid Nutrition 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000009789 rate limiting process Methods 0.000 description 1
- 239000005871 repellent Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 230000005469 synchrotron radiation Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/656—Manganese, technetium or rhenium
- B01J23/6562—Manganese
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/02—Impregnation, coating or precipitation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
- B01J37/348—Electrochemical processes, e.g. electrochemical deposition or anodisation
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/052—Electrodes comprising one or more electrocatalytic coatings on a substrate
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/052—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
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
- C25B11/056—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of textile or non-woven fabric
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
- C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
- C25B11/061—Metal or alloy
- C25B11/063—Valve metal, e.g. titanium
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
- C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
- C25B11/065—Carbon
-
- 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
-
- 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
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
- C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
- C25B9/23—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D9/00—Electrolytic coating other than with metals
- C25D9/04—Electrolytic coating other than with metals with inorganic materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
- B01J2235/30—Scanning electron microscopy; Transmission electron microscopy
-
- 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
Definitions
- the present invention relates to an iridium-manganese oxide composite material for a water-splitting catalyst, an iridium-manganese oxide composite electrode material, a membrane-electrode assembly, and methods for producing these. More specifically, it is used as an anode catalyst for oxygen generation in industrial water electrolysis performed under alkaline, neutral, or acidic conditions, or in water electrolysis using a polymer electrolyte membrane (PEM) type electrolytic cell.
- PEM polymer electrolyte membrane
- the present invention relates to an iridium-manganese oxide composite material, an iridium-manganese oxide composite electrode material, a membrane-electrode assembly, and methods for producing these.
- the water electrolysis method is one of the effective means for electrolyzing water to produce high-purity hydrogen gas from the cathode, and is characterized by simultaneous generation of oxygen from the counter electrode, the anode.
- it is necessary to use an electrode catalyst with a low hydrogen overvoltage at the cathode and an electrode catalyst with a low oxygen overvoltage at the anode, while maintaining a low electrolysis voltage. be.
- Electrode catalyst materials that are excellent in low oxygen overvoltage of the anode.
- Compounds have been proposed (Patent Documents 1 and 2, Non-Patent Documents 1 to 3).
- Non-Patent Document 4 iridium (Ir) is widely known as a highly active oxygen evolution electrode catalyst. Since it is very small, it is predicted that even if the water electrolysis technology spreads in the future, it will not be possible to supply a sufficient amount of catalyst. Electrocatalysts composed of such platinum group metals are very expensive, and thus alternative electrode catalysts using inexpensive transition metals have been developed. For example, in recent years, transition metal materials composed of manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), etc. have been proposed (Patent Documents 3 and 4, Non-Patent Documents 5 to 8 ).
- the catalyst materials composed of transition metals that have been proposed so far have a problem that their activity is remarkably low (high oxygen overvoltage) as compared with platinum group metal-based electrode catalysts. That is, an oxygen generating electrode catalyst material composed of inexpensive transition metals and having high catalytic activity comparable to platinum group metals such as Pt and Ir has not been realized.
- an oxygen generating electrode catalyst material composed of inexpensive transition metals and having high catalytic activity comparable to platinum group metals such as Pt and Ir has not been realized.
- manganese oxides having an oxygen evolution electrode catalytic activity equal to or higher than that of Pt were found, but Ir-based catalysts, which are said to exhibit the highest activity among platinum group metal elements, have been found. The activity was not as high as that of the active ingredient, and further development was eagerly awaited (Patent Document 5).
- An object of the present invention is to provide an iridium-manganese oxide composite material for a water-splitting catalyst, an iridium-manganese oxide composite electrode material, a membrane-electrode assembly, and a method for producing them. More specifically, it is an anode catalyst material for oxygen generation in industrial water electrolysis performed under alkaline, neutral, or acidic conditions, or in water electrolysis using a polymer electrolyte membrane (PEM) type electrolytic cell.
- PEM polymer electrolyte membrane
- an iridium-manganese oxide composite material for a water-splitting catalyst (hereinafter sometimes referred to as the iridium-manganese oxide of the present invention), which is cheaper than the current iridium catalyst system and has high oxygen evolution catalytic activity, water
- the present invention relates to an iridium-manganese oxide composite electrode material for a decomposition catalyst, a membrane-electrode assembly using the iridium-manganese oxide composite material, and a method for producing the same.
- the inventors of the present invention have extensively studied a catalyst material used as an oxygen generating electrode catalyst for water electrolysis, and found that at least iridium is dispersed on the surface of manganese oxide and the metal valence of iridium is 3.1 or more.
- the present inventors have found that an iridium-manganese oxide composite material with an iridium content of 3.8 or less exhibits high oxygen evolution electrocatalytic activity and excellent durability even with an extremely small amount of iridium, and have completed the present invention.
- the present invention provides iridium for an oxygen generating electrode catalyst in water electrolysis, wherein iridium is dispersed on at least the surface of a manganese oxide, and the metal valence of iridium is 3.1 or more and 3.8 or less.
- iridium-manganese oxide composite electrode material in which at least a portion of a conductive substrate composed of conductive fibers is coated with the iridium-manganese oxide composite material of the present invention, has a particularly high oxygen evolution rate. It was found to exhibit electrocatalytic activity.
- the present invention is an iridium-manganese oxide composite electrode material for an oxygen generating electrode, in which the iridium-manganese oxide composite material of the present invention covers at least a portion of a conductive substrate composed of conductive fibers.
- the gist of the present invention is as follows. [1] An iridium-manganese oxide composite material, characterized in that iridium is dispersed on at least the surface of the manganese oxide, and the metal valence of iridium is 3.1 or more and 3.8 or less.
- the iridium content when at least part of the conductive substrate is coated with the iridium-manganese oxide composite material is 0.01 mg/ cm2 or more and 0.2 mg/cm2 per geometric area of the conductive substrate. cm 2 or less, the iridium-manganese oxide composite material according to the above [1].
- Composite material is 0.2 atomic % or more and 10 atomic % or less.
- the manganese content when at least part of the conductive substrate is coated with the iridium-manganese oxide composite material is 0.12 mg/ cm2 or more and 14.35 mg/cm2 per geometric area of the conductive substrate.
- the iridium-manganese oxide composite material according to any one of the above [1] to [7].
- the iridium-manganese oxide composite material according to any one of [1] to [10] above is coated on at least a part of a conductive substrate composed of conductive fibers.
- iridium-manganese oxide composite electrode material [12] The above-mentioned [11], wherein the iridium-manganese oxide composite material covers 0.1 mg/cm 2 or more and 20 mg/cm 2 or less per geometric area of the conductive substrate. iridium-manganese oxide composite electrode material. [13] The iridium-manganese oxide composite electrode material according to the above [11] or [12], wherein the conductive substrate is made of carbon, titanium, or platinum-coated titanium.
- a membrane-electrode assembly comprising an electrode supporting the iridium-manganese oxide composite material according to any one of [1] to [10] above, and a polymer electrolyte membrane.
- a method for producing an iridium-manganese oxide composite material according to any one of [1] to [10] above, wherein the manganese oxide obtained by electrolysis of a mixed solution containing sulfuric acid and manganese sulfate is A method for producing an iridium-manganese oxide composite material, characterized in that annealing is performed after immersion in or contact with a salt solution.
- [20] A method for producing an iridium-manganese oxide composite electrode material according to any one of [11] to [13] above, wherein a mixed solution containing sulfuric acid and manganese sulfate is electrolyzed to make the manganese oxide conductive. Electrodeposit on at least a part of a conductive substrate composed of conductive fibers, then immerse or contact an iridium salt solution to uniformly disperse and adsorb iridium on at least the surface of manganese oxide, and then anneal.
- a method for producing an iridium-manganese oxide composite electrode material characterized by performing [21] The method for producing an iridium-manganese oxide composite electrode material according to [20] above, wherein the mixed solution containing sulfuric acid-manganese sulfate has a sulfuric acid concentration of 5 g/L or more and 65 g/L or less. . [22] The above-mentioned [20] or [21], wherein the mixed solution containing sulfuric acid and manganese sulfate is electrolyzed at a current density of 0.3 mA/cm 2 or more and 20 mA/cm 2 or less. A method for producing an iridium-manganese oxide composite electrode material.
- a membrane-electrode assembly comprising the oxygen generating electrode according to [26] above and a polymer electrolyte membrane.
- a water electrolysis device comprising the iridium-manganese oxide composite electrode material according to any one of [11] to [13] above or the oxygen generating electrode according to [26] above.
- the iridium-manganese oxide composite material of the present invention and the iridium-manganese oxide composite electrode material of the present invention can be used in industrial water electrolysis performed under alkaline, neutral or acidic conditions, and in PEM type electrolytic cells. In the water electrolysis used, it exhibits high activity and durability, and acts as an inexpensive and excellent anode catalyst for oxygen generation. Further, by adding carbon dioxide to the electrolytic system using the iridium-manganese oxide composite material of the present invention and the iridium-manganese oxide composite electrode material of the present invention, the carbon dioxide or the like is reduced at the cathode. , hydrocarbon compounds (formic acid, formaldehyde, methanol, methane, ethane, propane, etc.) can also be produced.
- hydrocarbon compounds formic acid, formaldehyde, methanol, methane, ethane, propane, etc.
- FIG. 1 is a cross-sectional SEM photograph of the iridium-manganese oxide composite electrode material of Example 1.
- FIG. 4 is a distribution photograph of each element of O, Ir, and Mn corresponding to the SEM photograph of the iridium-manganese oxide composite material layer in the iridium-manganese oxide composite electrode material of Example 1.
- FIG. Fig. 2 shows XRD patterns of the iridium-manganese oxide composite electrode material of Example 1 and the platinum-coated titanium mesh conductive substrate.
- Linear sweep voltammogram showing the relationship between current and potential (voltage) measured using ⁇ PEM type electrolytic cell> during oxygen generation (during water electrolysis) in Examples 1 to 3
- Comparative Example 1 Comparative Example 3 is.
- Time of electrolysis voltage measured at 80 ° C. and 1 A/cm 2 per geometric area of the conductive substrate using ⁇ PEM type electrolytic cell> during oxygen generation (during water electrolysis) in Examples 1 to 3 This is the data showing the transition.
- 2 is a linear sweep voltammogram showing the relationship between current and potential (voltage) measured using a ⁇ PEM type electrolytic cell> during oxygen generation (during water electrolysis) in Examples 4 to 6.
- FIG. Fig. 2 shows data showing the time course of electrolysis voltage measured at 80°C and 1.5 A/cm 2 using a ⁇ PEM type electrolytic cell> during oxygen generation (during water electrolysis) in Examples 4 to 6.
- the oxygen evolution reaction in the above formula 2 is generally regarded as the rate-limiting process of the overall reaction, and the development of a catalyst that can proceed with the reaction with a minimum amount of energy is an important position in this technical field,
- the present invention provides an oxygen-evolving electrode catalyst having a high water oxidation catalytic ability.
- iridium-manganese oxide composite material of the present invention iridium is dispersed on at least the surface of the manganese oxide, and the metal valence of iridium is 3.1 or more and 3.8 or less. Iridium is dispersed at least on the manganese oxide surface. For example, as shown in FIG.
- the Ir element is introduced after the manganese oxide is formed by the production method described later, it is reasonably considered that iridium is dispersed and arranged at least on the surface of the manganese oxide. If the metal valence of iridium is less than 3.1, the chemical stability as a catalyst material is low, and iridium ions are likely to be eluted and consumed particularly when used in an acidic environment such as PEM. Conversely, if the metal valence of iridium exceeds 3.8, the amount of trivalent iridium that effectively acts as an active center is small, resulting in a decrease in oxygen electrode catalytic activity. In order to exhibit excellent oxygen electrode catalytic activity, the metal valence of iridium is preferably 3.15 or more and 3.6 or less, more preferably 3.2 or more and 3.5 or less.
- the iridium content when at least part of the conductive substrate is coated with the iridium-manganese oxide composite material of the present invention is 0.01 mg/cm 2 or more and 0.2 mg/cm2 per geometric area of the conductive substrate. cm 2 or less is preferable.
- the iridium content is less than 0.01 mg/cm 2 , the characteristics of the manganese oxide single catalyst are obtained. Although it exhibits activity, it uses a large amount of iridium, a rare element, so it is expensive and impairs cost performance.
- the iridium content is more preferably 0.015 mg/cm 2 or more and 0.15 mg/cm 2 or less, and further preferably 0.02 mg/cm 2 or more and 0.1 mg/cm 2 or less.
- the geometric area corresponds to the projected area of the conductive base material, and the thickness of the base material is not considered.
- the iridium-manganese oxide composite material of the present invention preferably has an iridium metal content ratio (iridium/(iridium + manganese)) of 0.2 atomic % or more and 10 atomic % or less.
- the metal content ratio of iridium is important at least for dispersing iridium on the manganese oxide surface, and although the mutual relationship is not clear, it is also possible to control it within the metal valence range of iridium in the present invention. presumed to have an influence.
- the metal content ratio of iridium is less than 0.2 atomic percent, the characteristics of the manganese oxide single catalyst are obtained.
- the metal content ratio of iridium is preferably 0.3 atomic % or more and 5 atomic % or less, more preferably 0.4 atomic % or more and 2 atomic % or less.
- the peak position appearing in the XANES region of the Ir L3 absorption edge spectrum obtained from XAFS measurement is preferably 11200 eV or more and 11230 eV or less.
- the peak position of the spectrum in the XANES region tends to be influenced by the metal valence, and the peak position is located on the low energy side as the metal valence is low, and is located on the high energy side as the metal valence is high.
- the peak position appearing in the XANES region of the Ir L3 absorption edge spectrum is 11200 eV or more, so that the metal valence of iridium is maintained higher, and the chemical stability as a catalyst material is maintained higher.
- the elution of iridium ions can be further prevented.
- the peak position appearing in the XANES region of the Ir L3 absorption edge spectrum is 11230 eV or less, the amount of iridium that effectively acts as an active center can be maintained at a higher level, and the oxygen electrocatalytic activity can be maintained at a higher level.
- the peak position appearing in the XANES region of the Ir L3 absorption edge spectrum is 11210 eV or more and 11220 eV or less.
- the peak position corresponding to the bond between iridium and oxygen in the radial structure function obtained from XAFS measurement is preferably 1.0 ⁇ or more and 2.0 ⁇ or less.
- the value specified above is 1.0 ⁇ or more, it is possible to further prevent iridium from aggregating with each other and to maintain a higher dispersibility of iridium on the manganese oxide.
- the above specified value of 2.0 ⁇ or less allows for stronger interaction between iridium and oxygen and better protection against decay.
- the peak position corresponding to the bond between iridium and oxygen in the radial structure function obtained from XAFS measurement is 1.3 ⁇ or more and 1.6 ⁇ or less. is more preferable.
- the iridium-manganese oxide composite material of the present invention preferably has a BET specific surface area of 15 m 2 /g or more and 100 m 2 /g or less.
- the BET specific surface area mainly reflects the state of manganese oxide, and when the BET specific surface area is less than 15 m 2 /g, the active sites where iridium is adsorbed are limited, and the dispersed state of iridium, which effectively acts as a catalyst, decreases. do.
- the BET specific surface area exceeds 100 m 2 /g, the number of active sites where iridium can be adsorbed increases, but the manganese oxide film is porous and its strength is lowered, making it easier to collapse.
- the BET specific surface area of the iridium-manganese oxide composite material is more preferably 20 m 2 /g or more and 70 m 2 /g or less, and still more preferably 30 m 2 /g or more and 60 m 2 /g or less.
- the manganese oxide of the iridium-manganese oxide composite material of the present invention preferably has a manganese metal valence of 3.5 or more and 4.0 or less.
- a manganese metal valence of 3.5 or more and 4.0 or less the chemical stability as a catalyst material is low. Consumable.
- manganese oxides with a metal valence exceeding 4.0 also contain soluble pentavalent manganese and pentavalent manganese, and thus have low chemical stability. Therefore, in order to stably disperse iridium, the manganese oxide preferably has a manganese metal valence of 3.6 or more and 4.0 or less, more preferably 3.7 or more and 4.0 or less. .
- the energy corresponding to 0.5 when the edge jump in the XANES region of the MnK absorption edge spectrum obtained from XAFS measurement is normalized to 1 is 6520 eV or more and 6600 eV or less.
- the spectral energy positions appearing in the XANES region tend to be influenced by the metal valence.
- the value specified above is 6520 eV or more, the chemical stability as a catalyst material is maintained at a higher level, and especially when used in an acidic environment such as PEM, the elution of divalent manganese ions is further prevented. can.
- the manganese oxide more preferably has an energy of 6530 eV or more and 6560 eV corresponding to 0.5 when the edge jump in the XANES region of the MnK absorption edge spectrum is normalized to 1. .
- the manganese content when at least part of the conductive substrate is coated with the iridium-manganese oxide composite material of the present invention is 0.12 mg/cm 2 or more and 14.35 mg/cm2 or more per geometric area of the conductive substrate. cm 2 or less is preferable.
- the manganese content is 0.12 mg/cm 2 or more, the amount of iridium that can be adsorbed on the manganese oxide can be maintained, so that a higher catalytic activity can be maintained.
- the manganese content is 14.35 mg/cm 2 or less, the resistance of manganese oxide can be kept lower and the catalytic activity can be kept higher.
- the manganese content is more preferably 0.30 mg/cm 2 or more and 2.40 mg/cm 2 or less, and still more preferably 0.60 mg/cm 2 or more and 1.20 mg/cm 2 or less.
- the geometric area corresponds to the projected area of the conductive base material, and the thickness of the base material is not considered.
- the peak position corresponding to the binding of manganese and oxygen in the radial structure function obtained from XAFS measurement is preferably 1.0 ⁇ or more and 2.0 ⁇ or less.
- the value specified above is 1.0 ⁇ or more, the aggregation of manganese can be further prevented, and the dispersibility of iridium can be maintained at a higher level.
- the value specified above is 2.0 ⁇ or less, the interaction between manganese and oxygen and between manganese and manganese can be strengthened, and decay can be prevented more effectively.
- the peak position corresponding to the binding of manganese and oxygen in the radial structure function obtained from XAFS measurement is more preferably 1.3 ⁇ or more and 1.7 ⁇ or less.
- the manganese oxide of the iridium-manganese oxide composite material of the present invention includes, for example, electrolytic manganese dioxide obtained by an electrolytic method, manganese dioxide obtained by a chemical method, etc. Electrolytic manganese dioxide is preferable.
- the manganese oxide of the iridium-manganese oxide composite material of the present invention has a crystal phase having a basic crystal structure of either ⁇ -type, ⁇ -type, ⁇ -type, or ⁇ -type, or a mixture of these crystal structures. It may be mixed crystal manganese dioxide.
- the iridium-manganese oxide composite material of the present invention By supporting the iridium-manganese oxide composite material of the present invention on an electrode, the iridium-manganese oxide composite material of the present invention becomes an oxygen generating electrode active material in water electrolysis, and the oxygen generating electrode has a catalytic ability in a water splitting reaction. can be granted.
- a membrane-electrode assembly is obtained by laminating an oxygen generating electrode containing this oxygen generating electrode active material, a polymer electrolyte membrane, and an electrode provided with a hydrogen generating catalyst.
- examples of polymer electrolyte membranes include fluororesin-based cation exchange membranes
- examples of hydrogen generation catalysts include platinum microparticles.
- this oxygen generating electrode by having this oxygen generating electrode, it becomes a water electrolysis device, and hydrogen can be produced by water electrolysis using this oxygen generating electrode.
- the method for producing the iridium-manganese oxide composite material of the present invention is described below.
- the iridium-manganese oxide composite material of the present invention can be obtained, for example, by electrolytically depositing manganese oxide on an electrode substrate such as a pure titanium plate using a mixed solution containing sulfuric acid-manganese sulfate as an electrolytic solution, and obtaining an iridium salt. It can be obtained by annealing after immersion in or contact with a solution.
- the manganese oxide may be powdered by electrolytically depositing it using a mixed solution containing sulfuric acid and manganese sulfate, then peeling it off from the electrode substrate and pulverizing it.
- the sulfuric acid concentration is preferably controlled to 5 g/L or more and 65 g/L or less, and is preferably controlled to 20 g/L or more and 50 g/L or less. more preferred.
- the concentration of manganese (manganese ions of manganese sulfate) in the mixed solution is not particularly limited as long as it is less than the solubility, but is preferably 5 g/L or more and 50 g/L or less, and more preferably 10 g/L or more and 30 g/L or less. preferable.
- it is effective to appropriately add manganese sulfate corresponding to the manganese consumed in the electrolytic oxidation, or to continuously supply the manganese sulfate solution.
- the concentration of sulfuric acid in the mixed solution of sulfuric acid and manganese sulfate is a value excluding divalent anions (sulfate ions) of manganese sulfate.
- the electrolytic current density is not particularly limited, but is 0.3 mA/cm 2 or more per geometric area of the conductive substrate. It is preferably 20 mA/cm 2 or less. Thereby, manganese oxide can be electrolytically deposited efficiently and stably.
- the electrolytic current density is more preferably 1 mA/cm 2 or more and 10 mA/cm 2 or less, and further preferably 3 mA/cm 2 or more and 8 mA/cm 2 or less.
- the geometric area corresponds to the projected area of the conductive base material, and the thickness of the base material is not considered.
- the electrolysis temperature is 93° C. or higher and 98° C. or lower.
- the electrolysis temperature is preferably higher than 94° C., because the higher the electrolysis temperature, the higher the electrolytic production efficiency of the deposited manganese oxide.
- Manganese oxide electrolytically deposited on an electrode base material such as a pure titanium plate is peeled off from the electrode base material, then coarsely pulverized using a jaw crusher or the like, and then ground using a roller mill, a vertical mill, a Roche mill, a jet mill, or the like.
- manganese oxide as a simple substance is pulverized and adjusted to have a predetermined average secondary particle size.
- the manufactured manganese oxide undergoes a washing process and a neutralization process, and after removing residual electrolyte and the like, is dried using a flash drying apparatus or the like.
- a flash drying apparatus or the like submicron manganese oxide fine powder, which is a by-product of excessive pulverization in the pulverization step, can be recovered and separated by a dust collector bag filter or the like.
- a sintering step at 200° C. or higher and 500° C. or lower is performed to obtain manganese oxide.
- the manganese oxide is then immersed in a container containing the iridium salt solution or contacted with the manganese oxide and the iridium salt solution.
- Potassium hexachloroiridate (K 2 IrCl 6 ) or hexachloroiridate (H 2 IrCl 6 ) is exemplified as the type of iridium salt in the iridium salt solution.
- the iridium concentration in the iridium salt solution is not particularly limited as long as it is less than the solubility, it is preferably 0.1 g/L or more and 10 g/L or less, more preferably 0.3 g/L or more and 5 g/L or less.
- the conditions for immersing the manganese oxide in the iridium salt solution or contacting the manganese oxide with the iridium salt solution are not particularly limited, but the immersion or Contact is preferred. By setting the immersion time or contact time and the immersion temperature or contact temperature within the above ranges, the amount of iridium adsorbed onto the manganese oxide can be controlled.
- Annealing is then performed.
- Annealing conditions are not particularly limited, but are exemplified above 100° C. and 600° C. or less under air or nitrogen stream, and exemplified annealing treatment time is 10 minutes or more and 24 hours or less.
- the annealing temperature is preferably 300° C. or higher and 550° C. or lower, more preferably 350° C. or higher and 500° C. or lower.
- the annealing treatment time is preferably 1 hour or more and 16 hours or less, more preferably 2 hours or more and 8 hours or less.
- the iridium-manganese oxide composite electrode material of the present invention is obtained by coating at least a portion of a conductive base material composed of conductive fibers with the iridium-manganese oxide composite material of the present invention.
- the coating amount of the iridium-manganese oxide composite material of the present invention is preferably 0.1 mg/cm 2 or more and 20 mg/cm 2 or less per geometric area of the conductive substrate.
- the geometric area corresponds to the projected area of the conductive base material, and the thickness of the base material is not considered.
- the coating amount of the iridium-manganese oxide composite material of the present invention is within the above range, depending on the diameter and porosity of the fibers constituting the conductive substrate, the iridium-manganese oxide composite material is coated on the fibers. It is coated in an island-like manner or in such a manner as to cover the entire outer surface of the fiber, and the average coating thickness can be approximately 25 ⁇ m or less.
- the iridium-manganese oxide composite material coated on the fiber is composed of secondary particles, the average coating thickness and the average secondary particle size of the iridium-manganese oxide composite material constituting it are usually match.
- the average amount of the iridium-manganese oxide composite material coating the fibers of the conductive substrate is there is a relationship in which the thickness increases.
- the coating amount of the iridium-manganese oxide composite material is more preferably 0.2 mg/cm 2 or more and 10 mg/cm 2 or less, further preferably 0.3 mg/cm 2 or more and 7 mg/cm 2 or less, and 0.3 mg/cm 2 or more and 7 mg/cm 2 or less. 5 mg/cm 2 or more and 5 mg/cm 2 or less is particularly preferable.
- the thickness of the coating layer of the iridium-manganese oxide composite material is obtained, for example, by subtracting the wire diameter thickness of the conductive fiber, which is a constituent unit of the conductive base material, from the scanning electron microscope (SEM) image. You can also ask.
- the conductive substrate is preferably made of carbon, titanium, or platinum-coated titanium.
- carbon include carbon paper composed of conductive carbon fibers
- titanium include titanium nets composed of fibrous conductive metal titanium wires, sintered titanium, and the like.
- coated titanium include a platinum-coated titanium mesh obtained by coating the surface of a fibrous conductive metal titanium wire with platinum, and sintered titanium.
- the iridium-manganese oxide composite electrode material of the present invention uses a conductive substrate represented by carbon, titanium, or platinum-coated titanium instead of the pure titanium plate electrode substrate.
- a mixed solution containing sulfuric acid and manganese sulfate is electrolyzed to electrodeposit manganese oxide on at least a portion of a conductive substrate composed of conductive fibers, and then immersed in or contacted with an iridium salt solution to deposit iridium. is uniformly dispersed and adsorbed on at least the manganese oxide surface, and then subjected to annealing treatment.
- the iridium-manganese oxide composite electrode material is preferably coated so that the coating amount of the iridium-manganese oxide composite material per geometric area of the conductive substrate falls within the preferred range described above.
- the manganese oxide obtained by electrolysis of a mixed solution containing sulfuric acid and manganese sulfate is immersed in or brought into contact with an iridium salt solution, and then annealed.
- the iridium-manganese oxide composite material is deposited on the conductive substrate, and the iridium-manganese oxide composite material of the present invention is obtained.
- the sulfuric acid concentration is preferably 5 g/L or more and 65 g/L or less, and 20 g/L or more. 50 g/L or less is more preferable.
- the concentration of manganese (manganese ions of manganese sulfate) in the mixed solution is not particularly limited as long as it is less than the solubility, but is preferably 5 g/L or more and 50 g/L or less, more preferably 10 g/L or more and 30 g/L or less. .
- it is effective to appropriately add manganese sulfate corresponding to the manganese consumed in the electrolytic oxidation, or to continuously supply the manganese sulfate solution.
- the concentration of sulfuric acid in the mixed solution of sulfuric acid and manganese sulfate is a value excluding divalent anions (sulfate ions) of manganese sulfate.
- the electrolytic current density is not particularly limited, but is 0.3 mA/cm 2 per geometric area of the conductive substrate. It is preferable that it is 20 mA/cm 2 or more and 20 mA/cm 2 or less. Thereby, manganese oxide can be electrolytically deposited efficiently and stably.
- the electrolytic current density is more preferably 1 mA/cm 2 or more and 10 mA/cm 2 or less, and further 3 mA/cm 2 or more and 8 mA/dm 2 or less. preferable.
- the electrolysis temperature in the method for electrolytic deposition of manganese oxide from the iridium-manganese oxide composite electrode material of the present invention can be exemplified by 93° C. or higher and 98° C. or lower.
- the electrolysis temperature is preferably higher than 94° C., because the higher the electrolysis temperature, the higher the electrolytic production efficiency of the deposited manganese oxide.
- Potassium hexachloroiridate (K 2 IrCl 6 ) or hexachloroiridate (H 2 IrCl 6 ) is exemplified as the type of iridium salt in the iridium salt solution.
- the iridium concentration of the iridium salt solution is not particularly limited as long as it is less than the solubility, it is preferably 0.1 g/L or more and 10 g/L or less, more preferably 0.3 g/L or more and 5 g/L or less.
- the conductive base material is preferably made into a plate shape with a base thickness of 1 mm or less by molding or sintering conductive fibers such as carbon or titanium metal having a wire diameter of 100 ⁇ m or less, for example.
- the porosity of the conductive substrate is, for example, preferably 40% or more, more preferably 50% or more and 90% or less.
- the porosity is defined as the volume of a space portion without conductive fibers or the like in the volume of the conductive substrate.
- the conditions for electrolytically depositing the manganese oxide of the iridium-manganese oxide composite material of the present invention on the conductive substrate include, for example, the sulfuric acid concentration of the sulfuric acid-manganese sulfate mixed solution, the manganese concentration, and the electrolytic current.
- Each range of density, electrolysis temperature, etc. is selected, and the electrolysis time is in the range of 5 minutes to 120 minutes.
- the manganese oxide After the manganese oxide is electrolytically deposited on the conductive substrate, it is washed with water, dried, and then immersed in a container containing an iridium salt solution together with the conductive substrate on which the manganese oxide is electrolytically deposited, or manganese At least the manganese oxide surface is allowed to adsorb iridium by contacting the conductive substrate on which the oxide is electrolytically deposited with an iridium salt solution, etc., and finally, in an air or nitrogen atmosphere, the temperature is higher than 100 ° C. and 600 ° C. or less,
- the iridium-manganese oxide composite electrode material of the present invention can be obtained by performing the annealing treatment for more than 10 minutes and within 24 hours.
- the conditions for immersing the manganese oxide electrodeposited on at least a part of the conductive substrate composed of the conductive fibers in the iridium salt solution or contacting the manganese oxide and the iridium salt solution are not particularly limited. , immersion or contact for 30 minutes to 24 hours at a temperature of 20°C to 100°C. By setting the immersion time or contact time and the immersion temperature or contact temperature within the above ranges, the amount of iridium adsorbed onto the manganese oxide can be controlled.
- the annealing temperature is preferably 300° C. or higher and 550° C. or lower, more preferably 350° C. or higher and 500° C. or lower.
- the annealing treatment time is preferably 1 hour or more and 16 hours or less, more preferably 2 hours or more and 8 hours or less.
- the iridium-manganese oxide composite electrode material of the present invention when one side of the conductive substrate is shielded with a resin film or the like during electrolytic deposition of manganese oxide, the iridium-manganese oxide composite material is preferentially only on one side. It is also possible to intentionally disproportionately coat the iridium-manganese oxide composite material, while the other side can be coated almost entirely with the iridium-manganese oxide composite material.
- the interaction between iridium and manganese oxide is enhanced during annealing treatment, and the metal valence of iridium can be controlled within a desired range. It is presumed that the adhesion between the composite material and the conductive fiber is further enhanced, or the crystallinity of the iridium-manganese oxide composite material is further enhanced.
- a laminate is obtained by laminating the iridium-manganese oxide composite electrode material of the present invention, a polymer electrolyte membrane, and an electrode provided with a hydrogen generation catalyst.
- the present invention by having the iridium-manganese oxide composite electrode material of the present invention, it becomes a water electrolysis device, and hydrogen can be produced by water electrolysis using this iridium-manganese oxide composite electrode material. .
- ⁇ Metal concentration analysis of sulfuric acid-manganese sulfate mixed solution or iridium salt solution A mixed solution of sulfuric acid and manganese sulfate was diluted, and elemental manganese was quantitatively measured using ICP-AES (Optima 8300 manufactured by PerkinElmer). Further, the iridium salt solution was diluted, and the concentration of iridium element was quantitatively measured using a UV-Vis spectrometer (Shimadzu UV-2550).
- XAFS analysis of iridium-manganese oxide composite material was performed using the beamline BL14B2 of the large synchrotron radiation facility SPring-8.
- the Mn K absorption edge spectrum was measured by the transmission method using the Si (111) plane of a double crystal spectroscope.
- Ir L3 absorption edge spectra were measured by the fluorescence method using the Si(311) plane of a double crystal spectrometer.
- BET specific surface area of iridium-manganese oxide composite material and iridium-manganese oxide composite electrode material The BET specific surface area was measured by nitrogen adsorption by the BET single-point method. A gas adsorption type specific surface area measuring device (Flowsorb III, manufactured by Shimadzu Corporation) was used as the measuring device. Prior to the measurement, the measurement sample was degassed by heating at 150°C for 40 minutes.
- the BET specific surface area of only the conductive base material carbon network, titanium network, or platinum-coated titanium network is measured in advance, and the BET ratio for the conductive base material By subtracting the surface area, the BET specific surface area of only the iridium-manganese oxide composite material was obtained.
- the electrodeposition amount of manganese oxide and the coating amount of the iridium-manganese oxide composite material were measured according to the following methods. Before electrolytic deposition, the weight 1 of the base material (electrode base material such as titanium or conductive base material) is measured with a balance in advance, and after the electrolytic deposition, the weight 2 of the base material on which the manganese oxide has been electrodeposited is weighed. and the difference between weight 1 and weight 2 (weight 2-weight 1) was used to determine the amount of manganese oxide deposited.
- the coating amount of the iridium-manganese oxide composite material in the iridium-manganese oxide composite electrode material is The weight 3 of the coated substrate was measured with a balance, and the difference between the weight 1 and weight 3 of the substrate (weight 3-weight 1) was obtained.
- ⁇ Construction of PEM type electrolytic cell for evaluation of oxygen generating electrode catalyst characteristics Construction of a PEM-type electrolytic cell using a conductive substrate electrode material coated with an iridium-manganese oxide composite material was carried out as follows. An electrode material (plate mesh shape: 1 cm ⁇ 1 cm) is used as the working electrode, and a 20 wt% platinum-supported carbon catalyst (20% platinum on Vulcan XC-72, Item # PTC20-1, Fuel Cell Earth) is used as a catalyst for the counter electrode. , conductive catalyst ink was prepared, applied to carbon paper, and air-dried to prepare a counter electrode.
- a Nafion membrane Nafion 115, manufactured by Sigma-Aldrich
- the electrolyte membrane was cleaned and protonated (pretreated) by boiling in 3% hydrogen peroxide water, pure water, 1M sulfuric acid aqueous solution, and then pure water for 1 hour each.
- the electrolyte membrane is sandwiched between the catalyst-coated surfaces of the working electrode and the counter electrode, and hot-pressed for 3 minutes at 135° C. with a clamping force of 400 kg/cm 2 using a hot press machine (A-010D, manufactured by FC-R&D).
- a membrane/electrolyte assembly (MEA) was fabricated in this way. This MEA has a stainless steel mesh (#100) on the cathode side and a titanium mesh (#100) on the anode side to improve adhesion even during electrolysis operation. (manufactured by the company).
- ⁇ Electrochemical measurement 1 current-voltage curve measurement> In order to evaluate the catalytic ability to oxidize water in an actual device, a PEM-type electrolytic cell constructed using a conductive substrate electrode material coated with an iridium-manganese oxide composite material was used, and the operating temperature was 80. °C, current-voltage curve measurements were made. In this measurement, a two-electrode system consisting of only a working electrode and a counter electrode was used, and the current-voltage curve was measured by gradually increasing the applied voltage. Pure water was supplied to the PEM type electrolytic cell. The rate of voltage increase was set to 5 mV/s so that the voltage at which the current rises can be easily determined.
- Electrochemical measurement 2 Measurement of electrolytic voltage stability>
- a PEM type electrolytic cell constructed using a conductive substrate electrode material coated with an iridium-manganese oxide composite material was used.
- the electrolysis voltage was measured at an operating temperature of 80°C.
- a two-electrode system consisting of only a working electrode and a counter electrode was used, and while the current density applied between the two electrodes was kept at 1 A/cm 2 per geometric area of the conductive substrate, the time change of the electrolysis voltage was measured. Pure water was supplied to the PEM type electrolytic cell.
- Example 1 Electrolysis was performed in an electrolytic cell containing 35 g/L of sulfuric acid and a sulfuric acid-manganese sulfate mixed solution with a manganese sulfate concentration of 31 g/L, and a conductive base of a platinum-coated Ti mesh (ADL-414302-5056, manufactured by FC Development Co., Ltd.). Manganese oxide was electrolytically deposited on the material. Next, in an iridium salt solution bath containing 2.5 g/L of potassium hexachloroiridate (K 2 IrCl 6 ) and 0.5 g/L of sulfuric acid, the conductive substrate on which the manganese oxide was electrodeposited was placed at 95°C.
- K 2 IrCl 6 potassium hexachloroiridate
- the manganese oxide surface was immersed for 12 hours to adsorb iridium.
- the liquid in the iridium salt solution tank before and after the iridium was adsorbed was measured using a UV-Vis spectrometer (UV-2550 manufactured by Shimadzu Corporation).
- annealing treatment was performed in the air at 400° C. for 5 hours to prepare an iridium-manganese oxide composite electrode material by depositing the iridium-manganese oxide composite material on the conductive substrate.
- Table 1 shows the synthesis conditions.
- FIG. 1 The SEM photograph of the surface of this electrode material is shown in FIG. 1, and the SEM photograph of the cross section is shown in FIG. From FIG. 2, it was confirmed that the iridium-manganese oxide composite electrode material was in a state in which a catalyst layer of the iridium-manganese oxide composite material was deposited on platinum-coated Ti mesh fibers.
- FIG. 3 shows SEM-EDX data of a cross section of the iridium-manganese oxide composite catalyst layer. From FIG. 3, it was confirmed that iridium was uniformly dispersed at least on the manganese oxide surface.
- the XRD pattern of the iridium-manganese oxide composite electrode material obtained in Example 1 is shown in FIG. From FIG. 4, in addition to the diffraction lines of Pt and Ti derived from the conductive substrate, diffraction lines attributed to ⁇ -MnO 2 were observed. I didn't.
- the amount of manganese oxide deposited in this iridium-manganese oxide composite electrode material was 3.80 mg/cm 2
- the weight of the iridium-manganese oxide composite material was 3.88 mg/cm 2 .
- the iridium content of the oxide composite material was 0.08 mg/cm 2 and the metal content ratio of iridium (iridium/(manganese+iridium)) was 0.94 atomic %.
- the iridium-manganese oxide composite material of this iridium-manganese oxide composite electrode material was measured and analyzed by XPS, and the average metal valence of iridium was calculated to be 3.3, and the average metal valence of manganese was calculated to be 3.7. rice field.
- the BET specific surface area of this iridium-manganese oxide composite material was 42 m 2 /g.
- This iridium-manganese oxide composite electrode material is cut into a size of 1 cm ⁇ 1 cm, and a PEM type electrolytic cell is constructed according to the method of ⁇ Construction of PEM type electrolytic cell for evaluation of oxygen generating electrode catalyst characteristics>, ⁇ Electrochemical Measurement 1 Measurement of Current-Voltage Curve>, the characteristics of the oxygen generating electrode catalyst were evaluated. The results are shown in Table 2 and FIG. In addition, according to ⁇ Electrochemical Measurement 2 Measurement of Current-Voltage Curve>, change in electrolysis voltage over time was measured. The results are shown in FIG.
- Examples 2-3 An iridium-manganese oxide composite electrode material was produced according to the synthesis conditions of Example 1, except that the electrolytic solution composition, the electrodeposition time, the iridium salt solution composition, etc. for manganese oxide electrodeposition were changed. Table 1 shows these synthesis conditions, and Table 2 shows the physical properties and characteristic values of the iridium-manganese oxide composite material in the iridium-manganese oxide composite electrode material.
- FIG. 5 shows the results of the evaluation of the characteristics of the oxygen generating electrode catalyst, and
- FIG. 6 shows the results of measuring the change in electrolysis voltage over time.
- Examples 4-6 An iridium-manganese oxide composite electrode material was produced according to the synthesis conditions of Example 1, except that the electrodeposition time for manganese oxide deposition and the annealing temperature were changed. Table 4 shows these synthesis conditions, and Table 5 shows the physical properties and characteristic values of the iridium-manganese oxide composite material in the iridium-manganese oxide composite electrode material.
- FIG. 7 shows the results of the evaluation of the characteristics of the oxygen generating electrode catalyst, and FIG. 8 shows the results of measuring the change in electrolysis voltage over time.
- Comparative example 1 Using a commercially available iridium oxide catalyst (manufactured by Elyst), an anode with an iridium content of 0.08 mg/cm 2 and a membrane-electrode assembly were produced to construct a PEM type electrolytic cell. Oxygen evolution electrocatalyst evaluation was performed according to Curve Measurements. The characteristics evaluation results are shown in Table 2 and FIG.
- Comparative example 2 An anode and a membrane-electrode assembly were produced according to Comparative Example 1 except that the iridium content was 1 mg/cm 2 , and the oxygen generating electrode catalyst was evaluated. Table 2 shows the results of the characteristic evaluation.
- Comparative example 3 Electrolysis was performed in an electrolytic cell containing 35 g/L of sulfuric acid and a sulfuric acid-manganese sulfate mixed solution with a manganese sulfate concentration of 31 g/L, and a conductive base of a platinum-coated titanium mesh (ADL-414302-5056, manufactured by FC Development Co., Ltd.). Manganese oxide was electrolytically deposited on the material. Subsequently, annealing was performed at 450° C. for 5 hours in air to prepare a manganese oxide electrode material. Table 1 shows the synthesis conditions, and Table 2 shows the physical properties of this manganese oxide composite material.
- the iridium-manganese oxide composite material and the iridium-manganese oxide composite electrode material of the present invention have a structure that in principle increases the energy conversion efficiency, and the catalyst is made non-noble metal.
- the amount of iridium normally used is significantly reduced by 90% or more compared to commercially available iridium catalysts, and extremely good oxygen generation electrode catalyst activity and durability are shown. became clear.
- the iridium-manganese oxide composite material and the iridium - manganese oxide composite electrode material of the present invention are extremely It was found to exhibit good oxygen evolution electrocatalytic activity and durability.
- the iridium-manganese oxide composite material and the iridium-manganese oxide composite electrode material of the present invention are comparable to conventional noble metal-based catalysts, despite the fact that the amount of iridium used is significantly lower than that of conventional iridium-based catalysts. Due to its high oxygen generating electrode catalyst activity, it can be used as an anode catalyst for oxygen generation in industrial water electrolysis performed under alkaline or neutral conditions, or in water electrolysis using a PEM type electrolytic cell. It becomes possible to obtain low hydrogen and oxygen.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Electrochemistry (AREA)
- Metallurgy (AREA)
- Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Thermal Sciences (AREA)
- Health & Medical Sciences (AREA)
- Plasma & Fusion (AREA)
- Toxicology (AREA)
- Catalysts (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
Description
このような白金族金属で構成される電極触媒は非常に高価であることから、安価な遷移金属を用いた代替電極触媒の開発が進められてきている。例えば、近年では、マンガン(Mn)、鉄(Fe)、コバルト(Co)、ニッケル(Ni)などで構成される遷移金属材料が提案されている(特許文献3、4、非特許文献5~8)。
このような課題に対して、Ptと同等以上の酸素発生電極触媒活性を有するマンガン酸化物も見出されたが、白金族金属元素の中で最も高活性を示すとされるIr系の触媒の活性には及ばず、更なる開発が待ち望まれていた(特許文献5)。
より詳しくは、アルカリ性条件下、中性条件下、又は酸性条件下で行われる工業的な水電解や、固体高分子膜(PEM)型電解槽を用いる水電解における酸素発生用陽極触媒材料であって、現行のイリジウム触媒系よりも安価で、高い酸素発生触媒活性を有する水分解触媒用のイリジウム-マンガン酸化物複合材料(以下、本発明のイリジウム-マンガン酸化物という場合がある。)、水分解触媒用イリジウム-マンガン酸化物複合電極材料、イリジウム-マンガン酸化物複合材料を使用した膜-電極接合体及びそれらの製造方法に関する。
本発明者らは、本発明のイリジウム-マンガン酸化物複合材料によって導電性繊維で構成される導電性基材の少なくとも一部が被覆されたイリジウム-マンガン酸化物複合電極材料が、特に高い酸素発生電極触媒活性を示すことを見出した。すなわち、本発明は、本発明のイリジウム-マンガン酸化物複合材料が導電性繊維で構成される導電性基材の少なくとも一部を被覆した酸素発生電極用のイリジウム-マンガン酸化物複合電極材料である。
すなわち、本発明の要旨は以下のとおりである。
[1]少なくともマンガン酸化物表面にイリジウムが分散配置され、且つイリジウムの金属原子価が3.1以上3.8以下であることを特徴とするイリジウム-マンガン酸化物複合材料。
[2] 導電性基材の少なくとも一部をイリジウム-マンガン酸化物複合材料で被覆した際のイリジウムの含有量が、導電性基材の幾何面積あたり、0.01mg/cm2以上0.2mg/cm2以下であることを特徴とする上記[1]に記載のイリジウム-マンガン酸化物複合材料。
[3] 金属含有比(イリジウム/(マンガン+イリジウム))が、0.2原子%以上10原子%以下であることを特徴とする上記[1]又は[2]に記載のイリジウム-マンガン酸化物複合材料。
[4] XAFS測定から得られたIr L3吸収端スペクトルのXANES領域に現れるピーク位置が11200eV以上11230eV以下であることを特徴とする上記[1]~[3]のいずれかに記載のイリジウム-マンガン酸化物複合材料。
[5] XAFS測定から得られた動径構造関数におけるイリジウムと酸素の結合に相当するピーク位置が1.0Å以上2.0Å以下であることを特徴とする上記[1]~[4]のいずれかに記載のイリジウム-マンガン酸化物複合材料。
[6] BET比表面積が、15m2/g以上100m2/g以下であることを特徴とする上記[1]~[5]のいずれかに記載のイリジウム-マンガン酸化物複合材料。
[7] マンガン酸化物のマンガン金属原子価が3.5以上4.0以下であることを特徴とする上記[1]~[6]のいずれかに記載のイリジウム-マンガン酸化物複合材料。
[8] 導電性基材の少なくとも一部をイリジウム-マンガン酸化物複合材料で被覆した際のマンガンの含有量が、導電性基材の幾何面積あたり、0.12mg/cm2以上14.35mg/cm2以下であることを特徴とする上記[1]~[7]のいずれかに記載のイリジウム-マンガン酸化物複合材料。
[9] マンガン酸化物が電解二酸化マンガンであることを特徴とする上記[1]~[8]のいずれかに記載のイリジウム-マンガン酸化物複合材料。
[10] マンガン酸化物がγ型、β型、ε型、あるいはα型のいずれかの結晶相、または混晶の二酸化マンガンであることを特徴とする上記[1]~[9]のいずれかに記載のイリジウム-マンガン酸化物複合材料。
[11] 上記[1]~[10]のいずれかに記載のイリジウム-マンガン酸化物複合材料が、導電性繊維で構成される導電性基材の少なくとも一部に被覆されていることを特徴とするイリジウム-マンガン酸化物複合電極材料。
[12] 上記イリジウム-マンガン酸化物複合材料が、上記導電性基材の幾何面積あたり、0.1mg/cm2以上20mg/cm2以下被覆されていることを特徴とする上記[11]に記載のイリジウム-マンガン酸化物複合電極材料。
[13] 上記導電性基材が、カーボン、チタン、又は白金被覆されたチタンで構成される上記[11]又は[12]に記載のイリジウム-マンガン酸化物複合電極材料。
[14] 上記[1]~[10]のいずれかに記載のイリジウム-マンガン酸化物複合材料を担持させた電極と、高分子電解質膜とを有する膜-電極接合体。
[15] 上記[1]~[10]のいずれかに記載のイリジウム-マンガン酸化物複合材料の製造方法であって、硫酸-硫酸マンガンを含む混合溶液の電解で得られたマンガン酸化物をイリジウム塩溶液に浸漬または接触させた後、アニール処理を行うことを特徴とするイリジウム-マンガン酸化物複合材料の製造方法。
[16] 上記硫酸-硫酸マンガンを含む混合溶液の硫酸濃度が、5g/L以上65g/L以下であることを特徴とする上記[15]に記載のイリジウム-マンガン酸化物複合材料の製造方法。
[17] 上記硫酸-硫酸マンガンを含む混合溶液の電解が、0.3mA/cm2以上20mA/cm2以下の電流密度で行われることを特徴とする上記[15]又は[16]に記載のイリジウム-マンガン酸化物複合材料の製造方法。
[18] 上記イリジウム塩溶液におけるイリジウム塩が、K2IrCl6であることを特徴とする上記[15]~[17]のいずれかに記載のイリジウム-マンガン酸化物複合材料の製造方法。
[19] 上記アニール処理が、100℃を超え600℃以下、10分以上24時間以内で行われることを特徴とする上記[15]~[18]のいずれかに記載のイリジウム-マンガン酸化物複合材料の製造方法。
[20] 上記[11]~[13]のいずれかに記載のイリジウム-マンガン酸化物複合電極材料の製造方法であって、硫酸-硫酸マンガンを含む混合溶液を電解して、マンガン酸化物を導電性繊維で構成される導電性基材の少なくとも一部に電析させ、続いて、イリジウム塩溶液に浸漬または接触させてイリジウムを少なくともマンガン酸化物表面に均一分散して吸着させた後に、アニール処理を行うことを特徴とするイリジウム-マンガン酸化物複合電極材料の製造方法。
[21] 上記硫酸-硫酸マンガンを含む混合溶液の硫酸濃度が、5g/L以上65g/L以下であることを特徴とする上記[20]に記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
[22] 上記硫酸-硫酸マンガンを含む混合溶液の電解が、0.3mA/cm2以上20mA/cm2以下の電流密度で行われることを特徴とする上記[20]又は[21]に記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
[23] 上記イリジウム塩溶液におけるイリジウム塩が、K2IrCl6であることを特徴とする上記[20]~[22]のいずれかに記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
[24] 上記アニール処理が、100℃を超え600℃以下、10分以上24時間以内で行われることを特徴とする上記[20]~[23]のいずれかに記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
[25] 上記[1]~[10]のいずれかに記載のイリジウム-マンガン酸化物複合材料を含む水電解における酸素発生電極活物質。
[26] 上記[25]に記載の酸素発生電極活物質を含む酸素発生電極。
[27] 上記[26]に記載の酸素発生電極と、高分子電解質膜とを有する膜-電極接合体。
[28] 上記[11]~[13]のいずれかに記載のイリジウム-マンガン酸化物複合電極材料又は上記[26]に記載の酸素発生電極を有する水電解装置。
[29] 上記[11]~[13]のいずれかに記載のイリジウム-マンガン酸化物複合電極材料又は上記[26]に記載の酸素発生電極を使用して水電解する水素の製造方法。
また、本発明のイリジウム-マンガン酸化物複合材料、及び本発明のイリジウム-マンガン酸化物複合電極材料を用いる上記電解系に二酸化炭素を添加等することにより、該二酸化炭素等を陰極において還元して、炭化水素化合物(ギ酸、ホルムアルデヒド、メタノール、メタン、エタン、プロパン等)を製造することもできる。
まず、電解による水の分解について、PEM型の水電解のように反応場が酸性環境下になるような反応を例にとって、説明する。陰極触媒上では、式1に示されるように、2つのプロトンと2つの電子の反応により、水素が生成する。
2H+ + 2e- → H2 … 式1
2H2O → O2 + 4H+ + 4e- … 式2
そして、全体として、式3に示されるように、2つの水分子から、2つの水素分子とひとつの酸素分子が生成する反応となる。
2H2O → 2H2 + O2 … 式3
本発明のイリジウム-マンガン酸化物複合材料は、少なくともマンガン酸化物表面にイリジウムが分散配置され、且つイリジウムの金属原子価が3.1以上3.8以下である。イリジウムは少なくともマンガン酸化物表面に分散配置されている。例えば図3に示されたように、イリジウム-マンガン酸化物複合材料層のSEM写真像に対し、Mn、Oの各元素の存在場所を示す明コントラスト部分が全面的にあることが明らかであり、また図4のイリジウム-マンガン酸化物複合電極材料のXRDパターンから、イリジウム-マンガン酸化物複合材料層がγ構造のマンガン酸化物で構成されることが明らかであることから、まず主成分はマンガン酸化物である。次に、イリジウムは、例えば図3に示されたように、イリジウム-マンガン酸化物複合材料層のSEM写真像に対し、Ir元素の存在場所を示す明コントラスト部分が全面的にあることが明らかであり、また後述する製法により、Ir元素はマンガン酸化物が形成された後に導入されるものであることから、合理的に、イリジウムは少なくともマンガン酸化物表面に分散配置されていると考えられる。イリジウムの金属原子価が3.1を下回ると、触媒材料としての化学安定性が低く、特にPEMなどの酸性環境下で使用する場合にはイリジウムイオンとして溶出し消耗し易い。逆にイリジウムの金属原子価が3.8を超えると、活性中心として有効に作用する3価のイリジウムが少ないため、酸素電極触媒活性が低下する。優れた酸素電極触媒活性を発現するために、イリジウムの金属原子価は3.15以上3.6以下が好ましく、3.2以上3.5以下が更に好ましい。
また、本発明のイリジウム-マンガン酸化物複合材料のマンガン酸化物は、γ型、β型、ε型、あるいはα型のいずれかの基本結晶構造を有する結晶相、または、これらの結晶構造が混合された混晶の二酸化マンガンであっても良い。
本発明のイリジウム-マンガン酸化物複合材料は、例えば、電解液として、硫酸-硫酸マンガンを含む混合溶液を用いて、純チタン板などの電極基材にマンガン酸化物を電解析出させ、イリジウム塩溶液に浸漬または接触させた後、アニール処理することで得ることができる。
硫酸-硫酸マンガンを含む混合溶液中の各成分の濃度について、硫酸濃度としては5g/L以上65g/L以下に制御されることが好ましく、20g/L以上50g/L以下に制御されることがより好ましい。
上記混合溶液の成分濃度を維持するために、電解酸化で消費されたマンガンに相当する硫酸マンガンを適宜加えるか、あるいは硫酸マンガン溶液を連続的に供給することが有効である。
本発明のイリジウム-マンガン酸化物複合材料のマンガン酸化物の電解析出方法では、電解電流密度は、特に限定するものではないが、導電性基材の幾何面積あたり、0.3mA/cm2以上20mA/cm2以下であることが好ましい。これにより、効率的、かつ安定的にマンガン酸化物を電解析出させることができる。より安定的に本発明のイリジウム-マンガン酸化物複合材料を得るために、電解電流密度は1mA/cm2以上10mA/cm2以下がより好ましく、3mA/cm2以上8mA/cm2以下がさらに好ましい。ここに、幾何面積とは、導電性基材の投影面積に相当するものであり、基材の厚みは考慮しないものである。
純チタン板などの電極基材上に電解析出したマンガン酸化物は、該電極基材から剥離した後に、ジョークラッシャーなどの粗粉砕を経て、ローラーミル、竪型ミル、ロッシェミルやジェットミルなどで、マンガン酸化物単体として、所定の平均二次粒径になるように粉砕調整される。次に、製造したマンガン酸化物は、洗浄工程、中和工程を経て、残電解液などを除去した後に、フラッシュ乾燥装置などを用いて乾燥される。このフラッシュ乾燥時には、粉砕工程で過粉砕により副生したサブミクロンのマンガン酸化物の微粉を集塵機バグフィルターなどで回収し、分離することができる。また、さらに200℃以上500℃以下の焼成工程を施し、マンガン酸化物を得る場合もある。
イリジウム塩溶液のイリジウム塩の種類としては、ヘキサクロロイリジウム酸カリウム(K2IrCl6)又はヘキサクロロイリジウム酸(H2IrCl6)が例示される。
イリジウム塩溶液中のイリジウム濃度としても溶解度以下であれば特に制限はないが、0.1g/L以上10g/L以下が好ましく、0.3g/L以上5g/L以下がより好ましい。
本発明のイリジウム-マンガン酸化物複合電極材料は、上記本発明のイリジウム-マンガン酸化物複合材料が、導電性繊維から構成される導電性基材の少なくとも一部に被覆されているものである。この場合、本発明のイリジウム-マンガン酸化物複合材料の被覆量は、導電性基材の幾何面積あたり、0.1mg/cm2以上20mg/cm2以下が好ましい。ここに、幾何面積とは、導電性基材の投影面積に相当するものであり、基材の厚みは考慮しないものである。
上記混合溶液のマンガン(硫酸マンガンのマンガンイオン)の濃度としては、溶解度以下であれば特に制限はないが、5g/L以上50g/L以下が好ましく、10g/L以上30g/L以下がより好ましい。
上記混合溶液の成分濃度を維持するために、電解酸化で消費されたマンガンに相当する硫酸マンガンを適宜加えるか、あるいは硫酸マンガン溶液を連続的に供給することが有効である。
本発明のイリジウム-マンガン酸化物複合電極材料のマンガン酸化物の電解析出方法では、電解電流密度は、特に限定するものではないが、導電性基材の幾何面積あたり、0.3mA/cm2以上20mA/cm2以下であることが好ましい。これにより、効率的、かつ安定的にマンガン酸化物を電解析出させることができる。より安定的に本発明のイリジウム-マンガン酸化物複合電極材料を得るために、電解電流密度は1mA/cm2以上10mA/cm2以下がより好ましく、3mA/cm2以上8mA/dm2以下がさらに好ましい。
イリジウム塩溶液のイリジウム塩の種類としては、ヘキサクロロイリジウム酸カリウム(K2IrCl6)又はヘキサクロロイリジウム酸(H2IrCl6)が例示される。
イリジウム塩溶液のイリジウム濃度としても溶解度以下であれば特に制限はないが、0.1g/L以上10g/L以下が好ましく、0.3g/L以上5g/L以下がより好ましい。
アニール処理温度は、300℃以上550℃以下が好ましく、350℃以上500℃以下がより好ましい。また、アニール処理時間は、1時間以上16時間以下が好ましく、2時間以上8時間以下がより好ましい。
また、本発明のイリジウム-マンガン酸化物複合電極材料は、アニール処理時に、イリジウムとマンガン酸化物との相互作用が高められ、望ましい範囲のイリジウムの金属原子価に制御できるだけでなく、イリジウム-マンガン酸化物複合材料と導電性繊維との密着性がより高まる、又は、イリジウム-マンガン酸化物複合材料の結晶性がより高まるなど好適な効果があるものと推定している。
硫酸-硫酸マンガンの混合溶液を希釈し、ICP-AES(パーキンエルマー社製 Optima 8300)を用いてマンガン元素を定量測定した。また、イリジウム塩溶液を希釈し、UV-Visスペクトロメータ(島津社製 UV-2550)を用いて、イリジウム元素の濃度を定量測定した。
SEM-EDX装置(Hoskin Scientific社製 JSF-7800F)を使用して、表面形態、イリジウムの分散状態、並びに、断面の元素分析を行った。断面の元素分析を行う際には、導電性カーボンテープを用いてテーリングを防止した。
XPS分析装置(ULVAC社製 PHI 5000 Versa ProveII)を使用して、イリジウム、マンガンの金属原子価を求めた。線源にはAlKα(1486.6eV)を用いて、284.6eVのC1sスペクトルを結合エネルギーの基準とし、パスエナジー187.85eVとしてサーベイスキャン機能を利用した。Ir4fの高解像度分析には、11.75eVの低いパスエナジーを使用し、その他の元素の分析には、23.5eVのパスエナジーを使用した。得られたスペクトルの解析は、CasaXPSソフトウェアを用いて実施し、Ir4fスペクトルのフィッティングにはPfeiferが提唱するフィッティングモデルを、Mn2pスペクトルのフィッティングにはEugene S.Iltonが報告したモデルを使用した。
大型放射光施設SPring-8のビームラインBL14B2を用いてXAFS測定を行った。Mn K吸収端スペクトルは、二結晶分光器のSi(111)面を用いて透過法により測定した。Ir L3吸収端スペクトルは、二結晶分光器のSi(311)面を用いて蛍光法により測定した。
BET比表面積はBET1点法の窒素吸着により測定した。測定装置にはガス吸着式比表面積測定装置(フローソーブIII,島津社製)を用いた。測定に先立ち、150℃で40分間加熱することで測定試料を脱気処理した。イリジウム-マンガン酸化物複合電極材料の測定では、あらかじめ導電性基材であるカーボン網やチタン網あるいは、白金被覆したチタン網だけのBET比表面積を測定しておき、導電性基材分のBET比表面積を差し引くことで、イリジウム-マンガン酸化物複合材料だけのBET比表面積を求めた。
X線回折装置(Rigaku社製 Ultima+)を使用して、線源にはCuKα線(λ=1.5418Å)を用い、操作電位40kV、操作電流40mAでXRD測定を行った。イリジウム-マンガン酸化物複合電極材料のXRD測定では、導電性基材に由来するPtやTiの回折線も同時に検出された。
マンガン酸化物の電析量及びイリジウム-マンガン酸化物複合材料の被覆量は、以下の方法に従って測定された。
電解析出前に、あらかじめ基材(チタンなどの電極基材や導電性基材)の重量1を天秤で測定しておき、電解析出後にマンガン酸化物が電析した基材の重量2を天秤で測定し、重量1と重量2の差分(重量2-重量1)から、マンガン酸化物の電析量を求めた。
イリジウム-マンガン酸化物複合電極材料におけるイリジウム-マンガン酸化物複合材料の被覆量は、マンガン酸化物の電解析出、イリジウム塩溶液との接触、アニール処理を終えた後のイリジウム-マンガン酸化物複合材料が被覆された基材の重量3を天秤で測定し、基材の重量1と重量3の差分(重量3-重量1)から求めた。
イリジウム-マンガン酸化物複合材料を被覆させた導電性基材の電極材料を使用したPEM型電解槽の構築は、以下のように行った。電極材料(平板網形状:1cm×1cm)を作用極とし、対極用の触媒として、20wt%白金担持カーボン触媒(20% Platinum on Vulcan XC-72,Item#PTC20-1,Fuel Cell Earth)を用い、導電性触媒インクの作製、カーボンペーパーへの塗布を行い、風乾により対極の作製を行った。電解質膜としては、ナフィオン膜(ナフィオン115,Sigma-Aldrich社製)を用いた。電解質膜は、3%過酸化水素水、純水、1M硫酸水溶液、次いで純水中で各1時間煮沸することで洗浄・プロトン化(前処理)を行った。次に、作用極・対極の触媒塗布面で電解質膜を挟み、ホットプレス機(A-010D,FC-R&D社製)を用いて135℃、型締力400kg/cm2で3分間ホットプレスすることで膜/電解質接合体(MEA)を製作した。このMEAは、陰極側にステンレスメッシュ(#100)、陽極側にチタンメッシュ(#100)を介して、電解運転時でも密着性を向上させ、PEM型電解槽(WE-4S-RICW、エフシー開発社製)の筐体に取り付けた。
実デバイス中での水の酸化触媒能を評価するために、イリジウム-マンガン酸化物複合材料を被覆させた導電性基材の電極材料を用いて構築したPEM型電解槽を用いて、動作温度80℃で、電流-電圧曲線の測定を行った。本測定では、作用極・対極のみの二電極系を用い、印加する電圧を徐々に増加させることで電流-電圧曲線を測定した。PEM型電解槽には、純水を供給した。電圧の増加速度は、電流が立ち上がる電圧が判別し易いように留意して5mV/sとした。
実デバイス中での水の酸化触媒能の安定性を評価するために、イリジウム-マンガン酸化物複合材料を被覆させた導電性基材の電極材料を用いて構築したPEM型電解槽を用いて、動作温度80℃で、電解電圧の測定を行った。本測定では、作用極・対極のみの二電極系を用い、両極間に印加する電流密度を導電性基材の幾何面積あたり1A/cm2に保ちながら、電解電圧の時間変化を測定した。PEM型電解槽には、純水を供給した。
硫酸35g/L及び硫酸マンガン濃度31g/Lの硫酸-硫酸マンガン混合溶液が入った電解槽内で電解を行い、白金被覆したTi網(ADL-414302-5056、エフシー開発社製)の導電性基材上にマンガン酸化物を電解析出させた。次に、ヘキサクロロイリジウム酸カリウム(K2IrCl6)2.5g/L、硫酸0.5g/Lの入ったイリジウム塩溶液槽に、上記マンガン酸化物が電析した導電性基材を95℃で12時間浸漬し、マンガン酸化物表面にイリジウムを吸着させた。尚、イリジウムを吸着させた前後のイリジウム塩溶液槽の液を、UV-Visスペクトロメータ(島津社製 UV-2550)を用いて測定し、イリジウムが全てマンガン酸化物に吸着され、イリジウム塩溶液槽には残存していないことを確認している。続いて、空気下で400℃-5時間のアニール処理を行い、導電性基材にイリジウム-マンガン酸化物複合材料を析出させたイリジウム-マンガン酸化物複合電極材料を作製した。この合成条件について表1に示した。
マンガン酸化物電析の電解液組成、電析時間、イリジウム塩溶液組成などを変更した以外は実施例1の合成条件に従って、イリジウム-マンガン酸化物複合電極材料を作製した。これらの合成条件を表1に、イリジウム-マンガン酸化物複合電極材料におけるイリジウム-マンガン酸化物複合材料の物性、並びに特性値を表2に示した。また、酸素発生電極触媒特性評価の結果を図5に、電解電圧の時間変化測定の結果を図6に示した。
マンガン酸化物電析の電析時間とアニール処理温度を変更した以外は実施例1の合成条件に従って、イリジウム-マンガン酸化物複合電極材料を作製した。これらの合成条件を表4に、イリジウム-マンガン酸化物複合電極材料におけるイリジウム-マンガン酸化物複合材料の物性、並びに特性値を表5に示した。また、酸素発生電極触媒特性評価の結果を図7に、電解電圧の時間変化測定の結果を図8に示した。
市販の酸化イリジウム触媒(Elyst社製)を用い、イリジウム含有量0.08mg/cm2の陽極、膜-電極接合体を作製してPEM型電解槽を構築し、<電気化学測定1 電流-電圧曲線の測定>に従って、酸素発生電極触媒評価を行った。その特性評価結果を表2、図5に示した。
イリジウム含有量を1mg/cm2とする以外は比較例1に従って陽極、膜-電極接合体を作製し、酸素発生電極触媒評価を行った。その特性評価結果を表2に示した。
硫酸35g/L及び硫酸マンガン濃度31g/Lの硫酸-硫酸マンガン混合溶液が入った電解槽内で電解を行い、白金被覆したチタン網(ADL-414302-5056、エフシー開発社製)の導電性基材上にマンガン酸化物を電解析出させた。続いて、空気下で450℃-5時間のアニール処理を行い、マンガン酸化物電極材料を作製した。この合成条件について表1に、このマンガン酸化物複合材料の物性を表2に示した。次にこのマンガン酸化物電極材料を用いてPEM型電解槽を構築し、<電気化学測定 電流-電圧曲線の測定>に従って、酸素発生電極触媒評価を行った。その特性評価結果を表2、図5に示した。
また、上記水電解などの反応系に二酸化炭素を存在させることにより、該二酸化炭素等を陰極において還元して、炭化水素化合物(ギ酸、ホルムアルデヒド、メタノール、メタン、エタン、プロパン等)を製造することもできる。
なお、2021年6月15日に出願された日本特許出願2021-99336号の明細書、特許請求の範囲、図面、および要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。
Claims (29)
- 少なくともマンガン酸化物表面にイリジウムが分散配置され、且つイリジウムの金属原子価が3.1以上3.8以下であることを特徴とするイリジウム-マンガン酸化物複合材料。
- 導電性基材の少なくとも一部をイリジウム-マンガン酸化物複合材料で被覆した際のイリジウムの含有量が、導電性基材の幾何面積あたり、0.01mg/cm2以上0.2mg/cm2以下であることを特徴とする請求項1に記載のイリジウム-マンガン酸化物複合材料。
- 金属含有比(イリジウム/(マンガン+イリジウム))が、0.2原子%以上10原子%以下であることを特徴とする請求項1又は2に記載のイリジウム-マンガン酸化物複合材料。
- XAFS測定から得られたIr L3吸収端スペクトルのXANES領域に現れるピーク位置が11200eV以上11230eV以下であることを特徴とする請求項1~3のいずれか1項に記載のイリジウム-マンガン酸化物複合材料。
- XAFS測定から得られた動径構造関数におけるイリジウムと酸素の結合に相当するピーク位置が1.0Å以上2.0Å以下であることを特徴とする請求項1~4のいずれか1項に記載のイリジウム-マンガン酸化物複合材料。
- BET比表面積が、15m2/g以上100m2/g以下であることを特徴とする請求項1~5のいずれか1項に記載のイリジウム-マンガン酸化物複合材料。
- マンガン酸化物のマンガン金属原子価が3.5以上4.0以下であることを特徴とする請求項1~6のいずれか1項に記載のイリジウム-マンガン酸化物複合材料。
- 導電性基材の少なくとも一部をイリジウム-マンガン酸化物複合材料で被覆した際のマンガンの含有量が、導電性基材の幾何面積あたり、0.12mg/cm2以上14.35mg/cm2以下であることを特徴とする請求項1~7のいずれか1項に記載のイリジウム-マンガン酸化物複合材料。
- マンガン酸化物が電解二酸化マンガンであることを特徴とする請求項1~8のいずれか1項に記載のイリジウム-マンガン酸化物複合材料。
- マンガン酸化物がγ型、β型、ε型、あるいはα型のいずれかの結晶相、または混晶の二酸化マンガンであることを特徴とする請求項1~9のいずれか1項に記載のイリジウム-マンガン酸化物複合材料。
- 請求項1~10のいずれか1項に記載のイリジウム-マンガン酸化物複合材料が、導電性繊維で構成される導電性基材の少なくとも一部に被覆されていることを特徴とするイリジウム-マンガン酸化物複合電極材料。
- 前記イリジウム-マンガン酸化物複合材料が、前記導電性基材の幾何面積あたり、0.1mg/cm2以上20mg/cm2以下被覆されていることを特徴とする請求項11に記載のイリジウム-マンガン酸化物複合電極材料。
- 前記導電性基材が、カーボン、チタン、又は白金被覆されたチタンで構成される請求項11又は12に記載のイリジウム-マンガン酸化物複合電極材料。
- 請求項1~10のいずれか1項に記載のイリジウム-マンガン酸化物複合材料を担持させた電極と、高分子電解質膜とを有する膜-電極接合体。
- 請求項1~10のいずれか1項に記載のイリジウム-マンガン酸化物複合材料の製造方法であって、硫酸-硫酸マンガンを含む混合溶液の電解で得られたマンガン酸化物をイリジウム塩溶液に浸漬または接触させた後、アニール処理を行うことを特徴とするイリジウム-マンガン酸化物複合材料の製造方法。
- 前記硫酸-硫酸マンガンを含む混合溶液の硫酸濃度が、5g/L以上65g/L以下であることを特徴とする請求項15に記載のイリジウム-マンガン酸化物複合材料の製造方法。
- 前記硫酸-硫酸マンガンを含む混合溶液の電解が、0.3mA/cm2以上20mA/cm2以下の電流密度で行われることを特徴とする請求項15又は16に記載のイリジウム-マンガン酸化物複合材料の製造方法。
- 前記イリジウム塩溶液におけるイリジウム塩が、K2IrCl6であることを特徴とする請求項15~17のいずれか1項に記載のイリジウム-マンガン酸化物複合材料の製造方法。
- 前記アニール処理が、100℃を超え600℃以下、10分以上24時間以内で行われることを特徴とする請求項15~18のいずれか1項に記載のイリジウム-マンガン酸化物複合材料の製造方法。
- 請求項11~13のいずれか1項に記載のイリジウム-マンガン酸化物複合電極材料の製造方法であって、硫酸-硫酸マンガンを含む混合溶液を電解して、マンガン酸化物を導電性繊維で構成される導電性基材の少なくとも一部に電析させ、続いて、イリジウム塩溶液に浸漬または接触させてイリジウムを少なくともマンガン酸化物表面に均一分散して吸着させた後に、アニール処理を行うことを特徴とするイリジウム-マンガン酸化物複合電極材料の製造方法。
- 前記硫酸-硫酸マンガンを含む混合溶液の硫酸濃度が、5g/L以上65g/L以下であることを特徴とする請求項20に記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
- 前記硫酸-硫酸マンガンを含む混合溶液の電解が、0.3mA/cm2以上20mA/cm2以下の電流密度で行われることを特徴とする請求項20又は21に記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
- 前記イリジウム塩溶液におけるイリジウム塩が、K2IrCl6であることを特徴とする請求項20~22のいずれか1項に記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
- 前記アニール処理が、100℃を超え600℃以下、10分以上24時間以内で行われることを特徴とする請求項20~23のいずれか1項に記載のイリジウム-マンガン酸化物複合電極材料の製造方法。
- 請求項1~10のいずれか1項に記載のイリジウム-マンガン酸化物複合材料を含む水電解における酸素発生電極活物質。
- 請求項25に記載の酸素発生電極活物質を含む酸素発生電極。
- 請求項26に記載の酸素発生電極と、高分子電解質膜とを有する膜-電極接合体。
- 請求項11~13のいずれか1項に記載のイリジウム-マンガン酸化物複合電極材料又は請求項26に記載の酸素発生電極を有する水電解装置。
- 請求項11~13のいずれか1項に記載のイリジウム-マンガン酸化物複合電極材料又は請求項26に記載の酸素発生電極を使用して水電解する水素の製造方法。
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA3224016A CA3224016A1 (en) | 2021-06-15 | 2022-06-13 | Iridium-manganese oxide composite material, iridium-manganese oxide composite electrode material and methods for producing the same |
AU2022293119A AU2022293119A1 (en) | 2021-06-15 | 2022-06-13 | Iridium-manganese oxide composite material, iridium-manganese oxide composite electrode material, and methods for producing same |
JP2023529853A JP7477126B2 (ja) | 2021-06-15 | 2022-06-13 | イリジウム-マンガン酸化物複合材料、イリジウム-マンガン酸化物複合電極材料、及びこれらの製造方法 |
CN202280042437.4A CN117480278A (zh) | 2021-06-15 | 2022-06-13 | 铱-锰氧化物复合材料、铱-锰氧化物复合电极材料及其制造方法 |
EP22824949.6A EP4357485A1 (en) | 2021-06-15 | 2022-06-13 | Iridium-manganese oxide composite material, iridium-manganese oxide composite electrode material, and methods for producing same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2021-099336 | 2021-06-15 | ||
JP2021099336 | 2021-06-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2022264960A1 true WO2022264960A1 (ja) | 2022-12-22 |
Family
ID=84526474
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2022/023599 WO2022264960A1 (ja) | 2021-06-15 | 2022-06-13 | イリジウム-マンガン酸化物複合材料、イリジウム-マンガン酸化物複合電極材料、及びこれらの製造方法 |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP4357485A1 (ja) |
JP (1) | JP7477126B2 (ja) |
CN (1) | CN117480278A (ja) |
AU (1) | AU2022293119A1 (ja) |
CA (1) | CA3224016A1 (ja) |
WO (1) | WO2022264960A1 (ja) |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5773192A (en) * | 1980-08-18 | 1982-05-07 | Diamond Shamrock Corp | Electrode having outer coating for carrying out electrolytic method and protecting intermediate coating on electroconductive substrate and preparation thereof |
JPS58136790A (ja) * | 1982-02-05 | 1983-08-13 | Osaka Soda Co Ltd | 不溶性陽極 |
JPS59140383A (ja) * | 1983-02-01 | 1984-08-11 | Ishifuku Kinzoku Kogyo Kk | 電解用電極及びその製造方法 |
JPH08269761A (ja) | 1995-02-01 | 1996-10-15 | Japan Energy Corp | 水電解セルおよびその製造方法 |
JP2002263492A (ja) * | 2001-03-14 | 2002-09-17 | National Institute Of Advanced Industrial & Technology | イリジウム担持物質、イリジウム担持方法およびイリジウム担持触媒 |
WO2009154753A2 (en) | 2008-06-18 | 2009-12-23 | Massachusetts Institute Of Technology | Catalytic materials, electrodes, and systems for water electrolysis and other electrochemical techniques |
JP2015192993A (ja) | 2014-03-27 | 2015-11-05 | 国立研究開発法人理化学研究所 | 水分解用触媒、並びにそれを用いた酸素及び水素の製造方法 |
WO2019117199A1 (ja) | 2017-12-14 | 2019-06-20 | 国立研究開発法人理化学研究所 | 水分解触媒用のマンガン酸化物、マンガン酸化物-カーボン混合物、マンガン酸化物複合電極材料及びそれらの製造方法 |
JP2021099336A (ja) | 2019-12-19 | 2021-07-01 | 日鉄テックスエンジ株式会社 | 二次電池用充放電検査システム |
WO2021193467A1 (ja) * | 2020-03-25 | 2021-09-30 | 国立研究開発法人理化学研究所 | 水分解触媒用のマンガン-イリジウム複合酸化物、マンガン-イリジウム複合酸化物電極材料及びそれらの製造方法 |
-
2022
- 2022-06-13 WO PCT/JP2022/023599 patent/WO2022264960A1/ja active Application Filing
- 2022-06-13 CA CA3224016A patent/CA3224016A1/en active Pending
- 2022-06-13 AU AU2022293119A patent/AU2022293119A1/en active Pending
- 2022-06-13 EP EP22824949.6A patent/EP4357485A1/en active Pending
- 2022-06-13 JP JP2023529853A patent/JP7477126B2/ja active Active
- 2022-06-13 CN CN202280042437.4A patent/CN117480278A/zh active Pending
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5773192A (en) * | 1980-08-18 | 1982-05-07 | Diamond Shamrock Corp | Electrode having outer coating for carrying out electrolytic method and protecting intermediate coating on electroconductive substrate and preparation thereof |
JPS58136790A (ja) * | 1982-02-05 | 1983-08-13 | Osaka Soda Co Ltd | 不溶性陽極 |
JPS59140383A (ja) * | 1983-02-01 | 1984-08-11 | Ishifuku Kinzoku Kogyo Kk | 電解用電極及びその製造方法 |
JPH08269761A (ja) | 1995-02-01 | 1996-10-15 | Japan Energy Corp | 水電解セルおよびその製造方法 |
JP2002263492A (ja) * | 2001-03-14 | 2002-09-17 | National Institute Of Advanced Industrial & Technology | イリジウム担持物質、イリジウム担持方法およびイリジウム担持触媒 |
WO2009154753A2 (en) | 2008-06-18 | 2009-12-23 | Massachusetts Institute Of Technology | Catalytic materials, electrodes, and systems for water electrolysis and other electrochemical techniques |
JP2015192993A (ja) | 2014-03-27 | 2015-11-05 | 国立研究開発法人理化学研究所 | 水分解用触媒、並びにそれを用いた酸素及び水素の製造方法 |
WO2019117199A1 (ja) | 2017-12-14 | 2019-06-20 | 国立研究開発法人理化学研究所 | 水分解触媒用のマンガン酸化物、マンガン酸化物-カーボン混合物、マンガン酸化物複合電極材料及びそれらの製造方法 |
JP2021099336A (ja) | 2019-12-19 | 2021-07-01 | 日鉄テックスエンジ株式会社 | 二次電池用充放電検査システム |
WO2021193467A1 (ja) * | 2020-03-25 | 2021-09-30 | 国立研究開発法人理化学研究所 | 水分解触媒用のマンガン-イリジウム複合酸化物、マンガン-イリジウム複合酸化物電極材料及びそれらの製造方法 |
Non-Patent Citations (10)
Title |
---|
A. CHRISTENSEN, J. CHEM. SOC., FARADAY TRANS., vol. 1, no. 84, 1988, pages 2795 |
BIROL, WORLD ENERGY OUTLOOK, 2016 |
INTERNATIONAL ENERGY AGENCY (IEA, 2016 |
L. RIGSBYW. H. CASEYR. D. BRITTS. S. STAHL, J. AM. CHEM. SOC., vol. 133, 2011, pages 14431 |
M. DINCAY. SURENDRANATHD. G. NOCERA, PROC. NATL. ACAD. SCI. U.S.A. |
M. M. NAJAFPOURG. RENGERM. HOLYNSKAA. N. MOGHADDAME. -M. AROR. CARPENTIERH. NISHIHARAJ. J. EATON-RYEJ. -R. SHENS. I. ALLAKHVERDIEV, CHEM. REV., vol. 116, 2016, pages 2886 |
PFEIFER VERENA, JONES TRAVIS E., WRABETZ SABINE, MASSUÉ CYRIAC, VELASCO VÉLEZ JUAN J., ARRIGO ROSA, SCHERZER MICHAEL, PICCININ SIM: "Reactive oxygen species in iridium-based OER catalysts", CHEMICAL SCIENCE, ROYAL SOCIETY OF CHEMISTRY, UNITED KINGDOM, vol. 7, no. 11, 1 January 2016 (2016-01-01), United Kingdom , pages 6791 - 6795, XP093015525, ISSN: 2041-6520, DOI: 10.1039/C6SC01860B * |
S. TRASATTIG. BUZZANCA, J. ELECTROANAL. CHEM., vol. 29, 1971, pages A1 |
T. TAKASHIMAK. ISHIKAWAH. IRIE, J. PHYS. CHEM. C, vol. 120, 2016, pages 24827 |
Y. ZHAON. M. VARGAS-BARBOSAE. A. HERNANDEZ-PAGANT. E. MALLOUK, SMALL, vol. 7, 2011, pages 2087 |
Also Published As
Publication number | Publication date |
---|---|
CN117480278A (zh) | 2024-01-30 |
AU2022293119A1 (en) | 2024-01-18 |
JPWO2022264960A1 (ja) | 2022-12-22 |
EP4357485A1 (en) | 2024-04-24 |
CA3224016A1 (en) | 2022-12-22 |
JP7477126B2 (ja) | 2024-05-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Chen et al. | Mn-doped RuO2 nanocrystals as highly active electrocatalysts for enhanced oxygen evolution in acidic media | |
Xiong et al. | A strategy for increasing the efficiency of the oxygen reduction reaction in Mn-doped cobalt ferrites | |
Li et al. | Robust electrocatalysts from an alloyed Pt–Ru–M (M= Cr, Fe, Co, Ni, Mo)-decorated Ti mesh for hydrogen evolution by seawater splitting | |
Jeong et al. | Effect of graphene encapsulation of NiMo alloys on oxygen evolution reaction | |
Di Blasi et al. | Preparation and evaluation of RuO 2–IrO 2, IrO 2–Pt and IrO 2–Ta 2 O 5 catalysts for the oxygen evolution reaction in an SPE electrolyzer | |
JP2023060150A (ja) | 水分解触媒用のマンガン酸化物、マンガン酸化物-カーボン混合物、マンガン酸化物複合電極材料及びそれらの製造方法 | |
EP2600968A1 (en) | Catalyst | |
Ziegelbauer et al. | Chalcogenide electrocatalysts for oxygen-depolarized aqueous hydrochloric acid electrolysis | |
Elezović et al. | Synthesis and characterization of Pt catalysts on SnO2 based supports for oxygen reduction reaction | |
Wang et al. | Deciphering the exceptional performance of NiFe hydroxide for the oxygen evolution reaction in an anion exchange membrane electrolyzer | |
JP2023523614A (ja) | 白金族金属フリーの自立型酸素発生電極を有する陰イオン交換膜電解槽 | |
JP5072652B2 (ja) | 水電解装置 | |
Gharibi et al. | Palladium/Cobalt Coated on Multi‐Walled Carbon Nanotubes as an Electro‐catalyst for Oxygen Reduction Reaction in Passive Direct Methanol Fuel Cells | |
Kim et al. | Synthesis and electrochemical properties of nano-composite IrO2/TiO2 anode catalyst for SPE electrolysis cell | |
WO2021193467A1 (ja) | 水分解触媒用のマンガン-イリジウム複合酸化物、マンガン-イリジウム複合酸化物電極材料及びそれらの製造方法 | |
Tamilarasi et al. | Non-noble metal-based electro-catalyst for the oxygen evolution reaction (OER): Towards an active & stable electro-catalyst for PEM water electrolysis | |
WO2022264960A1 (ja) | イリジウム-マンガン酸化物複合材料、イリジウム-マンガン酸化物複合電極材料、及びこれらの製造方法 | |
KR20240035414A (ko) | 산소 발생 반응 촉매 | |
KR20210065252A (ko) | Ni-전이금속 복합 촉매를 포함하는 고내구성 전극 제조방법 및 이를 포함하는 고성능 고체산화물전해셀 | |
Li et al. | Atomically dispersed hexavalent iridium oxide from MnO2 reduction for oxygen evolution catalysis | |
JP2024085553A (ja) | マンガン酸化物-導電性繊維複合電極材料及びその製造方法 | |
Ye et al. | Pt‐IrO2 nanorod array electrode for oxygen evolution in PEM water electrolysis cell | |
KR102580737B1 (ko) | NiCoFe 층상이중수산화물의 제조 방법, NiCoFe 층상이중수산화물, 전극, 막전극접합체 및 이를 포함하는 수전해 시스템 | |
Gasteiger et al. | Polymer Electrolyte Fuel Cells 15 (PEFC 15) | |
Knani et al. | Low temperature electrochemical production of hydrogen: challenge in anode and cathode materials |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 22824949 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2023529853 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 18569341 Country of ref document: US |
|
WWE | Wipo information: entry into national phase |
Ref document number: 202280042437.4 Country of ref document: CN Ref document number: 3224016 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2022293119 Country of ref document: AU Ref document number: AU2022293119 Country of ref document: AU |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2022824949 Country of ref document: EP |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 2022293119 Country of ref document: AU Date of ref document: 20220613 Kind code of ref document: A |
|
ENP | Entry into the national phase |
Ref document number: 2022824949 Country of ref document: EP Effective date: 20240115 |