WO2024143238A1 - Catalyst for oxygen evolution reaction and production method therefor - Google Patents
Catalyst for oxygen evolution reaction and production method therefor Download PDFInfo
- Publication number
- WO2024143238A1 WO2024143238A1 PCT/JP2023/046304 JP2023046304W WO2024143238A1 WO 2024143238 A1 WO2024143238 A1 WO 2024143238A1 JP 2023046304 W JP2023046304 W JP 2023046304W WO 2024143238 A1 WO2024143238 A1 WO 2024143238A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- nickel
- carbon dioxide
- catalyst
- tungstate
- cathode
- Prior art date
Links
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 67
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 65
- 239000001301 oxygen Substances 0.000 title claims abstract description 65
- 239000003054 catalyst Substances 0.000 title claims abstract description 43
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 36
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 240
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 116
- SSWAPIFTNSBXIS-UHFFFAOYSA-N dioxido(dioxo)tungsten;iron(2+) Chemical compound [Fe+2].[O-][W]([O-])(=O)=O SSWAPIFTNSBXIS-UHFFFAOYSA-N 0.000 claims abstract description 37
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 94
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 91
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 47
- 239000001569 carbon dioxide Substances 0.000 claims description 45
- 150000003839 salts Chemical class 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 30
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 26
- 239000003513 alkali Substances 0.000 claims description 23
- 229920005862 polyol Polymers 0.000 claims description 23
- 150000003077 polyols Chemical class 0.000 claims description 23
- 238000010438 heat treatment Methods 0.000 claims description 17
- 238000003786 synthesis reaction Methods 0.000 claims description 15
- PBYZMCDFOULPGH-UHFFFAOYSA-N tungstate Chemical compound [O-][W]([O-])(=O)=O PBYZMCDFOULPGH-UHFFFAOYSA-N 0.000 claims description 14
- 239000011780 sodium chloride Substances 0.000 claims description 13
- 230000015572 biosynthetic process Effects 0.000 claims description 9
- 150000002505 iron Chemical class 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 7
- 238000009792 diffusion process Methods 0.000 claims description 6
- 230000002194 synthesizing effect Effects 0.000 claims description 5
- 230000003197 catalytic effect Effects 0.000 abstract description 21
- 230000000052 comparative effect Effects 0.000 description 31
- 239000000243 solution Substances 0.000 description 30
- 239000007809 chemical reaction catalyst Substances 0.000 description 28
- 238000005868 electrolysis reaction Methods 0.000 description 27
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 25
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 21
- 239000000758 substrate Substances 0.000 description 19
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 15
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 12
- 239000012153 distilled water Substances 0.000 description 12
- 229910052742 iron Inorganic materials 0.000 description 12
- 238000006722 reduction reaction Methods 0.000 description 12
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 11
- 239000012267 brine Substances 0.000 description 11
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 11
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 10
- 229910052721 tungsten Inorganic materials 0.000 description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 9
- 238000010586 diagram Methods 0.000 description 9
- 238000010992 reflux Methods 0.000 description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 8
- 238000002441 X-ray diffraction Methods 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 229910052739 hydrogen Inorganic materials 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 239000010937 tungsten Substances 0.000 description 8
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 7
- 238000004917 polyol method Methods 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- 238000001027 hydrothermal synthesis Methods 0.000 description 6
- 229910005507 FeWO4 Inorganic materials 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
- 238000013507 mapping Methods 0.000 description 5
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 5
- 239000010970 precious metal Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 229910001930 tungsten oxide Inorganic materials 0.000 description 5
- QWMFKVNJIYNWII-UHFFFAOYSA-N 5-bromo-2-(2,5-dimethylpyrrol-1-yl)pyridine Chemical compound CC1=CC=C(C)N1C1=CC=C(Br)C=N1 QWMFKVNJIYNWII-UHFFFAOYSA-N 0.000 description 4
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- HTXDPTMKBJXEOW-UHFFFAOYSA-N dioxoiridium Chemical compound O=[Ir]=O HTXDPTMKBJXEOW-UHFFFAOYSA-N 0.000 description 3
- 159000000011 group IA salts Chemical class 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 229910052741 iridium Inorganic materials 0.000 description 3
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 3
- PVFSDGKDKFSOTB-UHFFFAOYSA-K iron(3+);triacetate Chemical compound [Fe+3].CC([O-])=O.CC([O-])=O.CC([O-])=O PVFSDGKDKFSOTB-UHFFFAOYSA-K 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 3
- 239000011259 mixed solution Substances 0.000 description 3
- 229910000510 noble metal Inorganic materials 0.000 description 3
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 3
- 229910052707 ruthenium Inorganic materials 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- IKHGUXGNUITLKF-UHFFFAOYSA-N Acetaldehyde Chemical compound CC=O IKHGUXGNUITLKF-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- 229910000990 Ni alloy Inorganic materials 0.000 description 2
- 229910006167 NiWO4 Inorganic materials 0.000 description 2
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 description 2
- 239000010425 asbestos Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 description 2
- HUCVOHYBFXVBRW-UHFFFAOYSA-M caesium hydroxide Chemical compound [OH-].[Cs+] HUCVOHYBFXVBRW-UHFFFAOYSA-M 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 239000003014 ion exchange membrane Substances 0.000 description 2
- 238000004502 linear sweep voltammetry Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 229940078494 nickel acetate Drugs 0.000 description 2
- 238000010979 pH adjustment Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- YPFDHNVEDLHUCE-UHFFFAOYSA-N propane-1,3-diol Chemical compound OCCCO YPFDHNVEDLHUCE-UHFFFAOYSA-N 0.000 description 2
- 229910052895 riebeckite Inorganic materials 0.000 description 2
- XMVONEAAOPAGAO-UHFFFAOYSA-N sodium tungstate Chemical compound [Na+].[Na+].[O-][W]([O-])(=O)=O XMVONEAAOPAGAO-UHFFFAOYSA-N 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 150000004685 tetrahydrates Chemical class 0.000 description 2
- 238000001075 voltammogram Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 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 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- 229920000557 Nafion® Polymers 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004734 Polyphenylene sulfide Substances 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- UWHCKJMYHZGTIT-UHFFFAOYSA-N Tetraethylene glycol, Natural products OCCOCCOCCOCCO UWHCKJMYHZGTIT-UHFFFAOYSA-N 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- 239000011149 active material Substances 0.000 description 1
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- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000003011 anion exchange membrane Substances 0.000 description 1
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- 150000001722 carbon compounds Chemical class 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium 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
- 238000013329 compounding Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- SZXQTJUDPRGNJN-UHFFFAOYSA-N dipropylene glycol Chemical compound OCCCOCCCO SZXQTJUDPRGNJN-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
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- 229910021397 glassy carbon Inorganic materials 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000033444 hydroxylation Effects 0.000 description 1
- 238000005805 hydroxylation reaction Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 229910000457 iridium oxide Inorganic materials 0.000 description 1
- UGKDIUIOSMUOAW-UHFFFAOYSA-N iron nickel Chemical compound [Fe].[Ni] UGKDIUIOSMUOAW-UHFFFAOYSA-N 0.000 description 1
- 159000000014 iron salts Chemical class 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
- 239000000463 material Substances 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- 239000002135 nanosheet Substances 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
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- 230000005855 radiation Effects 0.000 description 1
- 238000002407 reforming Methods 0.000 description 1
- 230000027756 respiratory electron transport chain Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 229910001925 ruthenium oxide Inorganic materials 0.000 description 1
- WOCIAKWEIIZHES-UHFFFAOYSA-N ruthenium(iv) oxide Chemical compound O=[Ru]=O WOCIAKWEIIZHES-UHFFFAOYSA-N 0.000 description 1
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- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- 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
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/85—Chromium, molybdenum or tungsten
- B01J23/888—Tungsten
-
- 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
- B01J37/10—Heat treatment in the presence of water, e.g. steam
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/02—Hydrogen or oxygen
- C25B1/04—Hydrogen or oxygen by electrolysis of water
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
- C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
- C25B11/031—Porous electrodes
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
- C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
- C25B11/031—Porous electrodes
- C25B11/032—Gas diffusion electrodes
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/052—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
- C25B11/054—Electrodes comprising electrocatalysts supported on a carrier
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/055—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
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
- C25B11/077—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the compound being a non-noble metal oxide
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B3/00—Electrolytic production of organic compounds
- C25B3/20—Processes
- C25B3/25—Reduction
- C25B3/26—Reduction of carbon dioxide
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Definitions
- a representative method of water electrolysis is alkaline water electrolysis. Power loss occurs during alkaline water electrolysis, and the main causes of power loss include anode overvoltage, cathode overvoltage, ohmic loss in the ion-permeable diaphragm, and ohmic loss due to the structural resistance of the electrolysis cells that make up the electrolysis cell unit. If these power losses can be reduced, the current density during electrolysis in the electrolytic cell can be increased, making the entire system smaller, and as a result, it is possible to significantly reduce equipment costs. Therefore, there is a need to develop a catalyst that can reduce power loss.
- the amount of iron tungstate supported on the surface of the nickel porous body is not particularly limited as long as catalytic activity as a catalyst for oxygen generation reaction is obtained, but the mass per two-dimensional projected area of the nickel porous body is preferably 1 to 15 mg/cm 2 , more preferably 2 to 12 mg/cm 2.
- the two-dimensional projected area is the projected area excluding the void (opening) portion when the nickel porous body is viewed from directly above.
- the catalyst for oxygen generation reaction of the present invention can be used for an anode or a cathode, and can be used as a catalyst for oxygen generation reaction in, for example, electrolysis (electrolysis), batteries, etc.
- An embodiment of the method for producing the oxygen generating reaction catalyst of the present invention is a method for producing an oxygen generating reaction catalyst in which iron tungstate is synthesized in the presence of a nickel porous body and supported on the surface of the nickel porous body, in which the synthesis of iron tungstate is performed by dissolving a tungstate salt and an iron salt in a polyol and heating the polyol solution in which the tungstate salt and the iron salt are dissolved, or by putting the tungstate salt, the iron salt, and water into a pressure-resistant container and heating it.
- the heating temperature in the polyol method is not particularly limited, but a temperature near or below the boiling point of the polyol used as a solvent is preferred.
- the heating method is not particularly limited, but since the most heat can be applied at normal pressure when carrying out the synthesis reaction, it is preferable to reflux at a temperature near the boiling point of the polyol used.
- the heating time can be appropriately selected so that the synthesis reaction is carried out sufficiently. For example, an iron-containing salt and a tungsten-containing salt are dissolved in the polyol. At this time, water may be added appropriately, and the pH may be adjusted as necessary. This solution is heated and refluxed.
- the temperature of the solution is lowered to room temperature, and the nickel porous body is removed to obtain a nickel porous body carrying iron tungstate on its surface, i.e., the oxygen generating reaction catalyst of the present invention.
- the polyol acts as a protective agent for the surface of the generated iron tungstate particles, and is thought to prevent the particles from growing due to aggregation.
- Iron tungstate can be uniformly precipitated on the surface of the nickel porous body, and a catalyst for oxygen generating reaction with low overvoltage, large electrochemically active surface area, and high catalytic activity can be obtained.
- the polyol method allows synthesis at normal pressure in a polyol, so synthesis can be performed at a lower cost than the hydrothermal synthesis method, which requires a pressure-resistant container.
- the raw material of the iron tungstate in the present invention is not particularly limited as long as it is a substance that dissolves in water at a predetermined temperature and pressure in a pressure vessel, but for example, the tungsten source can be tungstate.
- tungstate salts include sodium tungstate, ammonium tungstate, calcium tungstate, etc.
- iron source can include iron salts, such as acetates, sulfates, nitrates, and chlorides, and various salts of divalent iron are preferred.
- Examples of the rigid conductive substrate include foils, plates, and the like of the above metals, expanded metals, punched metals, and the like, and examples of the flexible conductive substrate include wire mesh woven (or knitted) with metal wires.
- the method and amount of the oxygen generating reaction catalyst of the present invention supported on the conductive substrate are not particularly limited as long as the oxygen generating reaction catalyst of the present invention can contact the electrolyte and function as a catalyst.
- examples of the supporting method include a method in which the oxygen generating reaction catalyst of the present invention is attached to the entire or part of the surface of the conductive substrate using a binder, or a method in which the catalyst is mechanically contacted.
- the cathode in the present invention is not particularly limited as long as it is a substrate usable as an electrode for electrolysis, but usually includes a conductive substrate and a catalyst layer supported on the surface of the substrate.
- the conductive substrate is not particularly limited as long as it is a substrate usable as an electrode for electrolysis, and examples thereof include nickel, nickel alloy, stainless steel, mild steel, or stainless steel or mild steel with nickel plating on the surface.
- the conductive substrate may be, for example, a rigid substrate or a flexible substrate. Examples of rigid conductive substrates include expanded metal and punched metal, and examples of flexible conductive substrates include wire mesh woven (or knitted) with metal wires.
- FIG. 1 is a diagram showing a schematic configuration of the electrolytic cell of the present invention.
- the anode (positive electrode) is provided with the oxygen generating reaction catalyst of the present invention.
- the left side of the diaphragm is the anode chamber, and the right side is the cathode chamber, with the anode (positive electrode) disposed in the anode chamber and the cathode (negative electrode) disposed in the cathode chamber.
- water containing NaCl and KOH is supplied to the anode chamber, and water containing NaCl is supplied to the cathode chamber.
- the alkali refers to a compound that dissolves in water and exhibits basicity, and examples of such compounds include hydroxides of alkali metals and hydroxides of alkaline earth metals.
- FIG. 1 shows an example in which KOH is used as the alkali, but other than KOH, for example, NaOH, LiOH, CsOH, etc. can be used.
- salt water refers to an aqueous solution containing NaCl.
- Example 1 A nickel mesh piece cut to 1.2 cm x 1.2 cm was immersed in a 3 mol/L HCl solution and ultrasonically cleaned for 15 minutes, then immersed in ethanol and ultrasonically cleaned for 15 minutes, then immersed in water and ultrasonically cleaned for 15 minutes. 25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The pH-adjusted solution was transferred to a four-neck flask, and the nickel mesh washed as described above was immersed in the solution.
- the nickel mesh piece used (NI-318030, Nilaco Corporation) had a wire diameter of 0.15 mm, an opening of 0.697 mm, an aperture ratio of 67.7%, and a nickel purity of 99% or more.
- the same nickel mesh was used in Examples 2 to 4 and Comparative Examples 3 and 4.
- Example 1 the mass per two-dimensional projected area of the nickel mesh was 178.35 mg/cm 2 before the treatment and 188.67 mg/cm 2 after the treatment, so the amount of FeWO 4 supported per two-dimensional projected area of the nickel mesh was 10.32 mg/cm 2 .
- Examples 2 to 4 In Examples 2 to 4, nickel meshes were treated in the same manner as in Example 1, except that the reflux time was changed, to obtain nickel meshes carrying FeWO4 on their surfaces.
- the reflux time was 15 minutes in Example 2, 30 minutes in Example 3, and 180 minutes in Example 4.
- the amounts of FeWO4 carried were determined in the same manner as in Example 1, and were 2.2 mg/ cm2 in Example 2, 5.79 mg/ cm2 in Example 3, and 8.46 mg/ cm2 in Example 4.
- the nickel mesh after the treatment in Example 1 was observed by SEM (scanning electron microscope), and further mapping was performed by EDS (energy dispersive X-ray spectroscopy).
- the results are shown in FIG. 4.
- the upper right image in FIG. 4 is an enlarged image of the nickel mesh surface of the upper left image
- the lower left image is an enlarged image of the nickel mesh surface of the upper right image.
- the lower right is an EDS mapping image of the upper right part
- the image marked O shows the distribution of oxygen elements in red
- the image marked Fe shows the distribution of iron elements in green
- the image marked W shows the distribution of tungsten elements in blue
- the image marked Ni shows the distribution of nickel elements in reddish purple. From the SEM image and EDS mapping, it can be seen that a compound consisting of Fe, W, and O is uniformly precipitated on the surface of the nickel mesh and supported on the nickel mesh surface.
- X-Ray Diffraction The XRD pattern of the sample obtained in Example 1 was measured by an X-ray diffractometer (Rigaku Ultima 4) equipped with CuK ⁇ radiation (40 kv, 40 mA). For comparison, the XRD patterns of a nickel plate and a sample in which a nickel plate was used instead of a nickel mesh and treated in the same manner as in Example 1 were measured. The results are shown in FIG. 5.
- FeWO 4 _ NM indicates the results of the sample obtained in Example 1
- FeWO 4 _ Ni plate indicates the results of the nickel plate treated in the same manner as in Example 1
- Ni plate indicates the results of the nickel plate.
- the XRD patterns of the samples obtained in Comparative Examples 1 and 2 were measured.
- FIG. 6 The results are shown in FIG. 6.
- the upper side of FIG. 6 shows the results of Comparative Example 2, and the lower side of FIG. 6 shows the results of Comparative Example 1. It can be seen from the results in FIG. 6 that FeWO 4 was obtained in Comparative Example 1, and NiWO 4 was obtained in Comparative Example 2. Since the synthesis conditions of Comparative Example 1 are the same as those of Example 1, it can be seen that FeWO 4 is precipitated on the surface of the nickel mesh in Example 1 as a compound consisting of Fe, W and O. Also, since the synthesis conditions of Comparative Example 2 are the same as those of Comparative Example 3, it can be seen that NiWO 4 is precipitated on the surface of the nickel mesh in Comparative Example 3.
- Linear Sweep Voltammetry Linear sweep voltammetry was performed using the nickel mesh with FeWO 4 supported on its surface obtained in Example 1 as an electrode.
- a three-electrode cell was used, and the nickel mesh with FeWO 4 supported on its surface obtained in Example 1 was incorporated into a Teflon electrode holder with one side open to form a working electrode.
- the nickel mesh was exposed from the holder in a range of 1 cm vertical x 1 cm horizontal.
- a platinum mesh was used as the counter electrode (reference electrode), and Hg/HgO (1M NaOH) was used as the reference electrode.
- the reaction area of the nickel mesh with FeWO 4 supported on the working electrode was 0.19 cm 2.
- the reaction area was defined as the two-dimensional projected area of the nickel mesh.
- the two-dimensional projected area of the nickel mesh is the two-dimensional area excluding the voids (openings) when the nickel mesh is viewed from directly above, and was obtained in the same manner as in Example 1.
- 1M KOH purged with N 2 for 30 minutes was used as the electrolyte.
- the sweep rate was 1 mV/s.
- the resistance of the solution occurring between the working electrode and the reference electrode was compensated for by a feedback rate of 60%.
- the nickel meshes having FeWO 4 supported on the surface obtained in Examples 2 to 4 the nickel mesh having NiWO 4 supported on the surface obtained in Comparative Example 3, and the untreated nickel mesh of Comparative Example 4 were also tested in the same manner.
- the nickel mesh carrying FeWO 4 obtained in Example 1 shows an initial overvoltage comparable to IrO 2 (Comparative Example 5), and the overvoltage at a current density of 10 mA / cm 2 is lower than that of IrO 2 (Comparative Example 5). Furthermore, the Tafel slope is also smaller than that of IrO 2 (Comparative Example 5). The Tafel slope is the potential difference required for the current value to become 10 times, and the smaller the value, the faster the reaction rate and the more active it is, and it represents the speed of electron transfer in hydroxylation.
- the results in Table 1 show that the nickel mesh carrying FeWO 4 obtained in Example 1 has a significantly faster reaction rate than IrO 2 (Comparative Example 5) and the samples obtained in other Comparative Examples.
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Abstract
The present invention addresses the problem of providing a catalyst that has a high catalytic activity and can be used as a catalyst for oxygen evolution reaction. Provided is a catalyst for oxygen evolution reaction in which an iron tungstate is carried on the surface of a nickel porous body.
Description
本発明は、ニッケル多孔体の表面にタングステン酸鉄を担持した酸素発生反応用触媒、その製造方法、前記触媒を備えた電解槽並びに前記電解槽を使用する電解方法及び還元方法に関する。
The present invention relates to a catalyst for oxygen generation reactions in which iron tungstate is supported on the surface of a nickel porous body, a method for producing the catalyst, an electrolytic cell equipped with the catalyst, and an electrolysis method and a reduction method using the electrolytic cell.
近年、炭酸ガスの温室効果に起因する地球の温暖化等の問題を解決するため、再生可能エネルギーを利用して水素を製造する方法が注目されている。再生可能エネルギーを利用した水素の製造においては、化石燃料の改質による従来の水素製造方法に匹敵する低コスト化が求められている。この要求に応え得る水素製造方法として、水の電気分解（電解）が挙げられる。水の電気分解の代表的な方法としてはアルカリ水電解法がある。アルカリ水電解の際に電力損失が生じるが、電力損失の主たる要因としては、陽極の過電圧、陰極の過電圧、イオン透過性隔膜のオーム損、電解セルユニットを構成する電解セルの構造抵抗によるオーム損等が挙げられる。これらの電力損失を低減することができれば、電解槽の電解時の電流密度を高めてシステム全体を小型化し、その結果、設備費を大幅に削減することが可能になる。そのため、電力損失を低減できる触媒の開発が望まれている。
In recent years, methods of producing hydrogen using renewable energy have been attracting attention in order to solve problems such as global warming caused by the greenhouse effect of carbon dioxide. In hydrogen production using renewable energy, there is a demand for cost reduction comparable to conventional hydrogen production methods using fossil fuel reforming. One method of producing hydrogen that can meet this demand is water electrolysis. A representative method of water electrolysis is alkaline water electrolysis. Power loss occurs during alkaline water electrolysis, and the main causes of power loss include anode overvoltage, cathode overvoltage, ohmic loss in the ion-permeable diaphragm, and ohmic loss due to the structural resistance of the electrolysis cells that make up the electrolysis cell unit. If these power losses can be reduced, the current density during electrolysis in the electrolytic cell can be increased, making the entire system smaller, and as a result, it is possible to significantly reduce equipment costs. Therefore, there is a need to develop a catalyst that can reduce power loss.
従来、酸素発生反応用触媒としては、酸化ルテニウム、酸化イリジウム等が用いられているが、これらはコストが高く資源量が限られている貴金属を使用するものであった。そのため、貴金属よりもコストが低く資源量の多いタングステンを使用した酸素発生反応用触媒の開発が進められている。例えば、非特許文献１では、Ｎｉ－Ｆｅ－Ｗ層状水酸化物を表面積の大きいカーボンファイバーと複合化することにより酸素発生反応用触媒として使用することが報告され、特許文献１では、ＮｉｘＦｅ１－ｘＷＯ４（但し、０＜ｘ＜１）で表されるタングステン酸化物を酸素発生反応用触媒として使用することが報告されている。このように、ルテニウム、イリジウム等の貴金属を使用せずに高い触媒活性を示す様々な触媒の開発が進められ、ルテニウム、イリジウム等の貴金属を使用しなくても高い触媒活性が得られる触媒が求められていた。
Conventionally, ruthenium oxide, iridium oxide, and the like have been used as catalysts for oxygen generation reactions, but these use precious metals that are expensive and have limited resources. For this reason, development of catalysts for oxygen generation reactions using tungsten, which is less expensive and more abundant than precious metals, is underway. For example, Non-Patent Document 1 reports the use of Ni-Fe-W layered hydroxide as a catalyst for oxygen generation reactions by combining it with carbon fiber having a large surface area, and Patent Document 1 reports the use of tungsten oxide represented by Ni x Fe 1-x WO 4 (where 0<x<1) as a catalyst for oxygen generation reactions. In this way, various catalysts that exhibit high catalytic activity without using precious metals such as ruthenium and iridium have been developed, and there has been a demand for a catalyst that can obtain high catalytic activity without using precious metals such as ruthenium and iridium.
本発明は、酸素発生反応用触媒として使用できる触媒活性の高い触媒を提供することを課題とする。
The objective of the present invention is to provide a catalyst with high catalytic activity that can be used as a catalyst for oxygen generation reactions.
本発明者らは、ルテニウム、イリジウム等の貴金属を使用しなくても高い触媒活性を示すことができる酸素発生反応用触媒の開発を目指して、タングステン酸化物を利用した触媒の開発を行ってきた。開発を進めるなかで、タングステン酸鉄（II）（ＦｅＷＯ４）は触媒活性を示さないのに対し、ＮｉｘＦｅ１－ｘＷＯ４（但し、０＜ｘ＜１）で表されるタングステン酸化物は、優れた触媒活性を示すことを見いだし、この発明を特許出願している（特許文献１）。その後、本発明者らは開発を進めるなかで、ＦｅＷＯ４であってもニッケルメッシュ等のニッケル多孔体の表面に担持させ、ニッケル多孔体と複合化させることにより、優れた触媒活性を示し触媒として使用できることを見いだした。このようにして製造した触媒は、優れた触媒活性を有するだけでなく、ニッケル多孔体と複合化しているため、触媒粒子をバインダー、導電材等と混錬して使用する必要がなく、そのまま電極として使用することも可能であり、電極への使用が容易なものであった。この触媒は、ポリオール法等によるＦｅＷＯ４の合成時にニッケル多孔体を共存させることにより製造できるので製造も容易なものであった。本発明は、こうして完成されたものである。
The present inventors have been developing a catalyst using tungsten oxide, aiming to develop a catalyst for oxygen generation reaction that can exhibit high catalytic activity without using precious metals such as ruthenium and iridium. In the course of the development, they found that iron (II) tungstate (FeWO 4 ) does not exhibit catalytic activity, whereas tungsten oxide represented by Ni x Fe 1-x WO 4 (where 0<x<1) exhibits excellent catalytic activity, and filed a patent application for this invention (Patent Document 1). After that, in the course of the development, the present inventors found that even FeWO 4 can be used as a catalyst, exhibiting excellent catalytic activity, by supporting it on the surface of a nickel porous body such as a nickel mesh and compounding it with the nickel porous body. The catalyst produced in this way not only has excellent catalytic activity, but also is compounded with a nickel porous body, so there is no need to mix the catalyst particles with a binder, conductive material, etc. before use, and it can be used as an electrode as it is, and it was easy to use it as an electrode. This catalyst can be easily produced by synthesizing FeWO4 by the polyol method or the like in the presence of a nickel porous body. This is how the present invention was completed.
すなわち、本発明は以下に示す事項により特定されるものである。
（１）ニッケル多孔体の表面にタングステン酸鉄を担持した酸素発生反応用触媒。
（２）ニッケル多孔体がニッケルメッシュであることを特徴とする上記（１）の酸素発生反応用触媒。
（３）ニッケル多孔体の存在下でタングステン酸鉄を合成して前記ニッケル多孔体の表面に前記タングステン酸鉄を担持させる酸素発生反応用触媒の製造方法であって、前記タングステン酸鉄の合成が、タングステン酸塩及び鉄塩をポリオールに溶解させ、前記タングステン酸塩及び鉄塩が溶解したポリオール溶液を加熱することにより行われる、又はタングステン酸塩、鉄塩及び水を耐圧容器中に投入して加熱することにより行われる酸素発生反応用触媒の製造方法。
（４）ニッケル多孔体がニッケルメッシュであることを特徴とする上記（３）の酸素発生反応用触媒の製造方法。
（５）イオン透過性の隔膜によって区画された陽極室及び陰極室を備え、前記陽極室に陽極が配置され、前記陰極室に陰極が配置された電解槽であって、前記陽極がニッケル多孔体の表面にタングステン酸鉄を担持した酸素発生反応用触媒を備えた電解槽。
（６）二酸化炭素を陰極に供給するためのガス拡散層を備え、陰極室において二酸化炭素の還元を行う上記（５）の電解槽。
（７）陰極室の陽極室に対向する側の反対側に、二酸化炭素を陰極と接するように導入する二酸化炭素導入部を備え、前記二酸化炭素導入部において二酸化炭素の還元を行う上記（５）の電解槽。
（８）上記（５）の電解槽における陽極室にアルカリを含む水を供給し、陰極室に塩水を供給して塩水を電解する塩水の電解方法。
（９）陽極室に供給するアルカリを含む水が、アルカリを含む塩水である上記（８）の塩水の電解方法。
（１０）陰極室に供給する塩水が、アルカリを含む塩水である上記（８）又は（９）の塩水の電解方法。
（１１）上記（５）の電解槽における陽極室にアルカリを含む水を供給し、陰極室にＮａＣｌを含まずアルカリを含む水を供給して、アルカリを含む水を電解するアルカリを含む水の電解方法。
（１２）陽極室に供給するアルカリを含む水が、ＮａＣｌを含まずアルカリを含む水である上記（１１）のアルカリを含む水の電解方法。
（１３）上記（７）の電解槽における陽極室にアルカリを含む塩水を供給し、陰極室に塩水を供給し、二酸化炭素導入部に二酸化炭素を導入して、塩水を電解すると共に二酸化炭素の還元を行う塩水の電解及び二酸化炭素の還元方法。 That is, the present invention is specified by the following items.
(1) A catalyst for oxygen evolution reaction comprising a nickel porous body having iron tungstate supported on the surface thereof.
(2) The catalyst for oxygen generation reaction according to (1) above, wherein the nickel porous body is a nickel mesh.
(3) A method for producing a catalyst for oxygen generation reaction, which comprises synthesizing iron tungstate in the presence of a nickel porous body and supporting the iron tungstate on the surface of the nickel porous body, wherein the synthesis of the iron tungstate is carried out by dissolving a tungstate and an iron salt in a polyol and heating the polyol solution in which the tungstate and the iron salt are dissolved, or by putting a tungstate, an iron salt and water into a pressure-resistant container and heating the container.
(4) The method for producing a catalyst for oxygen generation reaction according to (3) above, characterized in that the nickel porous body is a nickel mesh.
(5) An electrolytic cell comprising an anode chamber and a cathode chamber separated by an ion-permeable diaphragm, an anode disposed in the anode chamber, and a cathode disposed in the cathode chamber, wherein the anode is provided with a catalyst for oxygen evolution reaction comprising iron tungstate supported on the surface of a nickel porous body.
(6) The electrolytic cell according to (5) above, which is provided with a gas diffusion layer for supplying carbon dioxide to the cathode, and in which reduction of carbon dioxide is carried out in the cathode chamber.
(7) The electrolytic cell according to (5) above, further comprising a carbon dioxide inlet for introducing carbon dioxide so as to come into contact with the cathode, on the side of the cathode chamber opposite the anode chamber, and wherein reduction of carbon dioxide is carried out in the carbon dioxide inlet.
(8) A method for electrolyzing brine, comprising the steps of: supplying alkali-containing water to the anode chamber of the electrolytic cell of (5) above; and supplying brine to the cathode chamber.
(9) The method for electrolyzing brine according to (8) above, wherein the alkali-containing water supplied to the anode chamber is alkali-containing brine.
(10) The method for electrolyzing brine according to (8) or (9) above, wherein the brine supplied to the cathode chamber is an alkali-containing brine.
(11) A method for electrolyzing alkaline water, comprising supplying alkaline water to the anode chamber of the electrolytic cell of (5) above and supplying alkaline water but not NaCl to the cathode chamber, thereby electrolyzing the alkaline water.
(12) The method for electrolyzing alkaline water according to (11), wherein the alkaline water to be supplied to the anode chamber is alkaline water containing no NaCl.
(13) A method for electrolyzing brine and reducing carbon dioxide, comprising the steps of: supplying an alkali-containing brine to the anode chamber of the electrolytic cell of (7) above; supplying the brine to the cathode chamber; and introducing carbon dioxide into the carbon dioxide inlet portion to electrolyze the brine and reduce the carbon dioxide.
（１）ニッケル多孔体の表面にタングステン酸鉄を担持した酸素発生反応用触媒。
（２）ニッケル多孔体がニッケルメッシュであることを特徴とする上記（１）の酸素発生反応用触媒。
（３）ニッケル多孔体の存在下でタングステン酸鉄を合成して前記ニッケル多孔体の表面に前記タングステン酸鉄を担持させる酸素発生反応用触媒の製造方法であって、前記タングステン酸鉄の合成が、タングステン酸塩及び鉄塩をポリオールに溶解させ、前記タングステン酸塩及び鉄塩が溶解したポリオール溶液を加熱することにより行われる、又はタングステン酸塩、鉄塩及び水を耐圧容器中に投入して加熱することにより行われる酸素発生反応用触媒の製造方法。
（４）ニッケル多孔体がニッケルメッシュであることを特徴とする上記（３）の酸素発生反応用触媒の製造方法。
（５）イオン透過性の隔膜によって区画された陽極室及び陰極室を備え、前記陽極室に陽極が配置され、前記陰極室に陰極が配置された電解槽であって、前記陽極がニッケル多孔体の表面にタングステン酸鉄を担持した酸素発生反応用触媒を備えた電解槽。
（６）二酸化炭素を陰極に供給するためのガス拡散層を備え、陰極室において二酸化炭素の還元を行う上記（５）の電解槽。
（７）陰極室の陽極室に対向する側の反対側に、二酸化炭素を陰極と接するように導入する二酸化炭素導入部を備え、前記二酸化炭素導入部において二酸化炭素の還元を行う上記（５）の電解槽。
（８）上記（５）の電解槽における陽極室にアルカリを含む水を供給し、陰極室に塩水を供給して塩水を電解する塩水の電解方法。
（９）陽極室に供給するアルカリを含む水が、アルカリを含む塩水である上記（８）の塩水の電解方法。
（１０）陰極室に供給する塩水が、アルカリを含む塩水である上記（８）又は（９）の塩水の電解方法。
（１１）上記（５）の電解槽における陽極室にアルカリを含む水を供給し、陰極室にＮａＣｌを含まずアルカリを含む水を供給して、アルカリを含む水を電解するアルカリを含む水の電解方法。
（１２）陽極室に供給するアルカリを含む水が、ＮａＣｌを含まずアルカリを含む水である上記（１１）のアルカリを含む水の電解方法。
（１３）上記（７）の電解槽における陽極室にアルカリを含む塩水を供給し、陰極室に塩水を供給し、二酸化炭素導入部に二酸化炭素を導入して、塩水を電解すると共に二酸化炭素の還元を行う塩水の電解及び二酸化炭素の還元方法。 That is, the present invention is specified by the following items.
(1) A catalyst for oxygen evolution reaction comprising a nickel porous body having iron tungstate supported on the surface thereof.
(2) The catalyst for oxygen generation reaction according to (1) above, wherein the nickel porous body is a nickel mesh.
(3) A method for producing a catalyst for oxygen generation reaction, which comprises synthesizing iron tungstate in the presence of a nickel porous body and supporting the iron tungstate on the surface of the nickel porous body, wherein the synthesis of the iron tungstate is carried out by dissolving a tungstate and an iron salt in a polyol and heating the polyol solution in which the tungstate and the iron salt are dissolved, or by putting a tungstate, an iron salt and water into a pressure-resistant container and heating the container.
(4) The method for producing a catalyst for oxygen generation reaction according to (3) above, characterized in that the nickel porous body is a nickel mesh.
(5) An electrolytic cell comprising an anode chamber and a cathode chamber separated by an ion-permeable diaphragm, an anode disposed in the anode chamber, and a cathode disposed in the cathode chamber, wherein the anode is provided with a catalyst for oxygen evolution reaction comprising iron tungstate supported on the surface of a nickel porous body.
(6) The electrolytic cell according to (5) above, which is provided with a gas diffusion layer for supplying carbon dioxide to the cathode, and in which reduction of carbon dioxide is carried out in the cathode chamber.
(7) The electrolytic cell according to (5) above, further comprising a carbon dioxide inlet for introducing carbon dioxide so as to come into contact with the cathode, on the side of the cathode chamber opposite the anode chamber, and wherein reduction of carbon dioxide is carried out in the carbon dioxide inlet.
(8) A method for electrolyzing brine, comprising the steps of: supplying alkali-containing water to the anode chamber of the electrolytic cell of (5) above; and supplying brine to the cathode chamber.
(9) The method for electrolyzing brine according to (8) above, wherein the alkali-containing water supplied to the anode chamber is alkali-containing brine.
(10) The method for electrolyzing brine according to (8) or (9) above, wherein the brine supplied to the cathode chamber is an alkali-containing brine.
(11) A method for electrolyzing alkaline water, comprising supplying alkaline water to the anode chamber of the electrolytic cell of (5) above and supplying alkaline water but not NaCl to the cathode chamber, thereby electrolyzing the alkaline water.
(12) The method for electrolyzing alkaline water according to (11), wherein the alkaline water to be supplied to the anode chamber is alkaline water containing no NaCl.
(13) A method for electrolyzing brine and reducing carbon dioxide, comprising the steps of: supplying an alkali-containing brine to the anode chamber of the electrolytic cell of (7) above; supplying the brine to the cathode chamber; and introducing carbon dioxide into the carbon dioxide inlet portion to electrolyze the brine and reduce the carbon dioxide.
本発明の酸素発生反応用触媒は、酸素発生反応用触媒として優れた触媒活性を示す。また、本発明の酸素発生反応用触媒は、製造及び電極への使用が容易である。本発明の酸素発生反応用触媒の製造方法は、優れた触媒活性を示す酸素発生反応用触媒を製造することができる。本発明の電解槽は、本発明の酸素発生反応用触媒を備えるので、塩水の電解や二酸化炭素の還元に好適に使用できる。
The oxygen generating reaction catalyst of the present invention exhibits excellent catalytic activity as an oxygen generating reaction catalyst. In addition, the oxygen generating reaction catalyst of the present invention is easy to manufacture and use in electrodes. The manufacturing method of the oxygen generating reaction catalyst of the present invention can manufacture an oxygen generating reaction catalyst that exhibits excellent catalytic activity. The electrolytic cell of the present invention is equipped with the oxygen generating reaction catalyst of the present invention, and therefore can be suitably used for electrolysis of salt water and reduction of carbon dioxide.
本発明の酸素発生反応用触媒は、ニッケル多孔体の表面にタングステン酸鉄を担持したものである。本発明におけるニッケル多孔体としては、ニッケルを基材とした多孔体であれば特に制限されず、例えば、ニッケルメッシュ、ニッケルのエキスパンドメタル、パンチングメタル、発泡金属等を挙げることができる。また、市販されているこれらのものを使用することもできる。本発明におけるニッケル多孔体の開口率としては１５～８０％が好ましく、５０～８０％がより好ましい。ニッケルの純度としては９８％以上が好ましい。本発明におけるニッケル多孔体としては、ニッケルメッシュが好ましい。本発明におけるニッケルメッシュとしては特に制限されないが、線径は０．０６～０．２５ｍｍが好ましく、目開きは０．０７～１．０３ｍｍが好ましい。市販されているニッケルメッシュを使用することもできる。本発明におけるタングステン酸鉄はＦｅＷＯ４で表されるタングステン酸鉄（II）である。
The catalyst for oxygen generation reaction of the present invention is a nickel porous body having iron tungstate supported on the surface thereof. The nickel porous body in the present invention is not particularly limited as long as it is a porous body based on nickel, and examples thereof include nickel mesh, nickel expanded metal, punching metal, and foam metal. Commercially available products can also be used. The aperture ratio of the nickel porous body in the present invention is preferably 15 to 80%, more preferably 50 to 80%. The purity of nickel is preferably 98% or more. The nickel porous body in the present invention is preferably nickel mesh. The nickel mesh in the present invention is not particularly limited, but the wire diameter is preferably 0.06 to 0.25 mm, and the mesh size is preferably 0.07 to 1.03 mm. Commercially available nickel mesh can also be used. The iron tungstate in the present invention is iron tungstate (II) represented by FeWO 4 .
本発明においては、ニッケル多孔体の表面にタングステン酸鉄が担持されている。ここで、担持されているとは、タングステン酸鉄がニッケル多孔体の表面に付着している状態をいい、例えば、物理的な付着、電気的な付着、化学結合による化学的な付着等、付着力の性質は問わない。また、付着の状態も、タングステン酸鉄が膜状に付着していてもよく、粒子状にタングステン酸鉄が付着していてもよい。ニッケル多孔体表面へのタングステン酸鉄の担持量としては、酸素発生反応用触媒としての触媒活性が得られれば特に制限されるものではないが、ニッケル多孔体の二次元投影面積あたりの質量が１～１５ｍｇ／ｃｍ２が好ましく、２～１２ｍｇ／ｃｍ２がより好ましい。ここで、二次元投影面積とは、ニッケル多孔体を真上から見たときの空隙（開口）部分を除いた投影面積である。本発明の酸素発生反応用触媒は、陽極又は正極に用いることができ、例えば、電気分解（電解）、電池等における酸素発生反応のための触媒として使用できる。本発明の酸素発生反応用触媒は、例えば、水の電気分解における陽極、金属空気電池における空気極（正極）、二酸化炭素の電解における還元反応の対極等に使用することができる。本発明の酸素発生反応用触媒が優れた触媒活性を示す理由はまだ明らかではないが、電解等を行う際にニッケル多孔体表面とタングステン酸鉄との界面でニッケル原子の移動がおこり、界面付近のタングステン酸鉄にニッケル原子が組み込まれることにより触媒活性が得られるとも考えられる。
In the present invention, iron tungstate is supported on the surface of the nickel porous body. Here, "supported" refers to a state in which iron tungstate is attached to the surface of the nickel porous body, and the nature of the adhesive force does not matter, for example, physical adhesion, electrical adhesion, chemical adhesion by chemical bonding, etc. In addition, the state of attachment may be such that iron tungstate is attached in the form of a film, or in the form of particles. The amount of iron tungstate supported on the surface of the nickel porous body is not particularly limited as long as catalytic activity as a catalyst for oxygen generation reaction is obtained, but the mass per two-dimensional projected area of the nickel porous body is preferably 1 to 15 mg/cm 2 , more preferably 2 to 12 mg/cm 2. Here, the two-dimensional projected area is the projected area excluding the void (opening) portion when the nickel porous body is viewed from directly above. The catalyst for oxygen generation reaction of the present invention can be used for an anode or a cathode, and can be used as a catalyst for oxygen generation reaction in, for example, electrolysis (electrolysis), batteries, etc. The oxygen generating reaction catalyst of the present invention can be used, for example, as an anode in the electrolysis of water, an air electrode (positive electrode) in a metal-air battery, a counter electrode in the reduction reaction in the electrolysis of carbon dioxide, etc. The reason why the oxygen generating reaction catalyst of the present invention exhibits excellent catalytic activity is not yet clear, but it is thought that the catalytic activity is obtained by the transfer of nickel atoms at the interface between the surface of the nickel porous body and the iron tungstate during electrolysis, etc., and the incorporation of nickel atoms into the iron tungstate near the interface.
本発明の酸素発生反応用触媒の製造方法としては、特に制限されるものではないが、例えば、ポリオール法、水熱合成法等によりタングステン酸鉄を合成する際に、タングステン酸鉄を合成する液中にニッケル多孔体を浸漬し、ニッケル多孔体の表面にタングステン酸鉄を析出させることにより、ニッケル多孔体の表面にタングステン酸鉄を担持させる方法を挙げることができる。本発明の酸素発生反応用触媒の製造方法の実施形態としては、ニッケル多孔体の存在下でタングステン酸鉄を合成してニッケル多孔体の表面にタングステン酸鉄を担持させる酸素発生反応用触媒の製造方法であって、タングステン酸鉄の合成が、タングステン酸塩及び鉄塩をポリオールに溶解させ、タングステン酸塩及び鉄塩が溶解したポリオール溶液を加熱することにより行われる、又はタングステン酸塩及び鉄塩並びに水を耐圧容器中に投入して加熱することにより行われる製造方法を挙げることができる。ポリオール法とは、原料の塩をポリオールに溶解させて加熱することにより目的とする生成物を得る方法であり、水熱合成法とは、耐圧密閉容器中に原料と水を入れ、容器を密閉したまま加熱することにより目的とする生成物を得る方法である。ポリオール法は、各種原料をポリオールに溶解させる工程、及び前記工程で得られたポリオール溶液を加熱する工程を含むが、ポリオール法を使用して本発明の酸素発生反応用触媒を製造する場合、使用するポリオールとしては特に制限されず、例えば、エチレングリコール、プロピレングリコール、テトラエチレングリコール、トリメチレングリコール、テトラメチレングリコール、ジエチレングリコール、ジプロピレングリコール、ポリエチレングリコール等を挙げることができる。ポリオールに溶解させる塩としては、本発明におけるタングステン酸鉄の構成成分である鉄及びタングステンの少なくとも１種を含む塩であり、使用するポリオールに溶解するものであれば特に制限されず、これらの塩を組み合わせて使用して溶解させ、ポリオール中に前記２成分が含まれるようにする。タングステン源としては、例えば、タングステン酸塩を挙げることができる。タングステン酸塩としては、タングステン酸ナトリウム、タングステン酸アンモニウム、タングステン酸カルシウム等を挙げることができる。鉄源としては、鉄の酢酸塩、硫酸塩、硝酸塩、塩化物等を挙げることができ、２価の鉄の各種塩が好ましい。
The method for producing the oxygen generating reaction catalyst of the present invention is not particularly limited, but may be, for example, a method in which, when synthesizing iron tungstate by a polyol method, a hydrothermal synthesis method, or the like, a nickel porous body is immersed in a solution for synthesizing iron tungstate, and iron tungstate is precipitated on the surface of the nickel porous body, thereby supporting iron tungstate on the surface of the nickel porous body. An embodiment of the method for producing the oxygen generating reaction catalyst of the present invention is a method for producing an oxygen generating reaction catalyst in which iron tungstate is synthesized in the presence of a nickel porous body and supported on the surface of the nickel porous body, in which the synthesis of iron tungstate is performed by dissolving a tungstate salt and an iron salt in a polyol and heating the polyol solution in which the tungstate salt and the iron salt are dissolved, or by putting the tungstate salt, the iron salt, and water into a pressure-resistant container and heating it. The polyol method is a method of obtaining a target product by dissolving a raw material salt in a polyol and heating the polyol, and the hydrothermal synthesis method is a method of obtaining a target product by putting raw materials and water in a pressure-resistant sealed container and heating the container while sealing it. The polyol method includes a step of dissolving various raw materials in a polyol and a step of heating the polyol solution obtained in the above step, but when the oxygen generating reaction catalyst of the present invention is produced using the polyol method, the polyol to be used is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, tetraethylene glycol, trimethylene glycol, tetramethylene glycol, diethylene glycol, dipropylene glycol, polyethylene glycol, etc. The salt to be dissolved in the polyol is a salt containing at least one of iron and tungsten, which are components of the iron tungstate in the present invention, and is not particularly limited as long as it is soluble in the polyol to be used, and these salts are used in combination and dissolved so that the two components are contained in the polyol. The tungsten source can be, for example, tungstate. Examples of tungstates include sodium tungstate, ammonium tungstate, and calcium tungstate. Examples of iron sources include iron acetate, sulfate, nitrate, and chloride, with various salts of divalent iron being preferred.
ポリオール法における加熱温度としては特に制限されないが、溶媒として使用するポリオールの沸点近傍あるいはそれ以下の温度が好ましい。また、加熱方法としては特に制限されないが、合成反応を行う際に常圧で最も多く熱を加えることができるため、使用するポリオールの沸点付近の温度で還流することが好ましい。加熱時間は、合成反応が十分に行われる時間を適宜選択することができる。例えば、鉄を含む塩及びタングステンを含む塩をポリオール中に溶解させる。このとき、適宜水を加えてもよく、必要に応じてｐＨを調整してもよい。この溶液を加熱還流する。このときの加熱温度は、使用するポリオールの種類、ポリオールに添加する水の量等によって異なるが、前記溶液が還流できる温度であればよい。加熱時間は、合成反応が十分に行われる時間であれば特に制限されないが、例えば、３０分～３時間、３０分～２時間等を挙げることができる。ニッケル多孔体は、各種塩を溶解する前のポリオール中に浸漬させてもよく、鉄とタングステンのうち一方を溶解させた段階で浸漬させてもよく、両成分を溶解させた段階で浸漬させてもよい。加熱中の合成反応によりニッケル多孔体の表面にタングステン酸鉄が析出する。合成反応終了後、前記溶液の温度を室温まで下げ、ニッケル多孔体を取り出すことにより、表面にタングステン酸鉄を担持したニッケル多孔体、すなわち本発明の酸素発生反応用触媒を得ることができる。ポリオールを溶媒として使用することにより、ポリオールが、生成するタングステン酸鉄粒子表面の保護剤として働き、粒子の凝集による成長を妨げると考えられ、ニッケル多孔体の表面に均一にタングステン酸鉄を析出させることができ、過電圧が低く、大きな電気化学活性表面積を有し、高い触媒活性を有する酸素発生反応用触媒を得ることができる。また、ポリオール法は、ポリオール中において常圧で合成できるので、耐圧容器が必要となる水熱合成法に比べて低いコストで合成できる。
The heating temperature in the polyol method is not particularly limited, but a temperature near or below the boiling point of the polyol used as a solvent is preferred. The heating method is not particularly limited, but since the most heat can be applied at normal pressure when carrying out the synthesis reaction, it is preferable to reflux at a temperature near the boiling point of the polyol used. The heating time can be appropriately selected so that the synthesis reaction is carried out sufficiently. For example, an iron-containing salt and a tungsten-containing salt are dissolved in the polyol. At this time, water may be added appropriately, and the pH may be adjusted as necessary. This solution is heated and refluxed. The heating temperature at this time varies depending on the type of polyol used, the amount of water added to the polyol, etc., but it is sufficient as long as the solution can be refluxed. The heating time is not particularly limited so long as the synthesis reaction is carried out sufficiently, but examples include 30 minutes to 3 hours, 30 minutes to 2 hours, etc. The nickel porous body may be immersed in the polyol before dissolving various salts, or may be immersed at the stage where one of iron and tungsten is dissolved, or may be immersed at the stage where both components are dissolved. The synthesis reaction during heating causes iron tungstate to precipitate on the surface of the nickel porous body. After the synthesis reaction is completed, the temperature of the solution is lowered to room temperature, and the nickel porous body is removed to obtain a nickel porous body carrying iron tungstate on its surface, i.e., the oxygen generating reaction catalyst of the present invention. By using a polyol as a solvent, the polyol acts as a protective agent for the surface of the generated iron tungstate particles, and is thought to prevent the particles from growing due to aggregation. Iron tungstate can be uniformly precipitated on the surface of the nickel porous body, and a catalyst for oxygen generating reaction with low overvoltage, large electrochemically active surface area, and high catalytic activity can be obtained. In addition, the polyol method allows synthesis at normal pressure in a polyol, so synthesis can be performed at a lower cost than the hydrothermal synthesis method, which requires a pressure-resistant container.
水熱合成法により本発明の酸素発生反応用触媒を製造する場合、本発明におけるタングステン酸鉄の原料としては、耐圧容器中の所定の温度圧力で水に溶解する物質であれば特に制限されないが、例えば、タングステン源としては、タングステン酸塩を挙げることができる。タングステン酸塩としては、タングステン酸ナトリウム、タングステン酸アンモニウム、タングステン酸カルシウム等を挙げることができる。また、鉄源としては、例えば、鉄の塩を挙げることができ、酢酸塩、硫酸塩、硝酸塩、塩化物等を挙げることができ、２価の鉄の各種塩が好ましい。水熱合成法では、例えば、タングステン源となる原料及び鉄源となる原料並びにニッケル多孔体を水と共に耐圧容器中に入れて加熱し、所定の温度、圧力で所定時間反応させることにより、本発明の酸素発生反応用触媒を製造することができる。水熱合成法における温度及び圧力は、使用する原料に応じて適宜選択することができるが、例えば、温度としては１００～２００℃を挙げることができ、その場合圧力としては１～１５気圧程度となる。合成時間としては、合成反応が十分に行われる時間であれば特に制限されないが、例えば、１２～４８時間を挙げることができる。合成後、耐圧容器内の温度、圧力を下げ、タングステン酸鉄が表面に析出したニッケル多孔体を取り出すことにより本発明の酸素発生反応用触媒を得ることができる。
When the oxygen generating reaction catalyst of the present invention is produced by hydrothermal synthesis, the raw material of the iron tungstate in the present invention is not particularly limited as long as it is a substance that dissolves in water at a predetermined temperature and pressure in a pressure vessel, but for example, the tungsten source can be tungstate. Examples of tungstate salts include sodium tungstate, ammonium tungstate, calcium tungstate, etc. Also, examples of the iron source can include iron salts, such as acetates, sulfates, nitrates, and chlorides, and various salts of divalent iron are preferred. In the hydrothermal synthesis method, for example, the raw material that serves as the tungsten source and the raw material that serves as the iron source, as well as the nickel porous body, are placed in a pressure vessel together with water, heated, and reacted at a predetermined temperature and pressure for a predetermined time, thereby producing the oxygen generating reaction catalyst of the present invention. The temperature and pressure in the hydrothermal synthesis method can be appropriately selected depending on the raw material used, but for example, the temperature can be 100 to 200°C, and in that case, the pressure is about 1 to 15 atmospheres. The synthesis time is not particularly limited as long as the synthesis reaction is carried out sufficiently, but can be, for example, 12 to 48 hours. After synthesis, the temperature and pressure in the pressure-resistant vessel are lowered, and the nickel porous body with iron tungstate precipitated on the surface is taken out to obtain the oxygen generation reaction catalyst of the present invention.
本発明の電解槽は、イオン透過性の隔膜によって区画された陽極室及び陰極室を備え、前記陽極室に陽極が配置され、前記陰極室に陰極が配置された電解槽であって、前記陽極はニッケル多孔体の表面にタングステン酸鉄を担持した本発明の酸素発生反応用触媒を備える。本発明におけるイオン透過性の隔膜としては、水溶液等の電解用の電解槽に使用可能なイオン透過性の隔膜であれば特に制限されず、例えば、アスベストや変性アスベストからなる多孔質膜、ポリスルホン系ポリマーを用いた多孔質隔膜、ポリフェニレンスルファイド繊維を用いた布、フッ素系多孔質膜、無機系材料と有機系材料との両方を含むハイブリッド材料を用いた多孔質膜等の多孔質隔膜、フッ素系イオン交換膜、炭化水素系イオン交換膜等のイオン交換膜などを挙げることができる。本発明におけるイオン透過性の隔膜としては、ガス透過性が低く、電気伝導度が小さく、強度が高いことが好ましい。本発明の酸素発生反応用触媒は、ニッケルメッシュ等のニッケル多孔体の表面にタングステン酸鉄を担持させているため、本発明の酸素発生反応用触媒そのものを陽極として使用することができる。また、本発明の酸素発生反応用触媒を更に導電性基材に担持させて陽極として使用してもよい。導電性基材としては、例えば、ニッケル、ニッケル合金、ニッケル鉄、バナジウム、モリブデン、銅、銀、マンガン、白金族元素、黒鉛、若しくはクロム、又はそれらの組合せを挙げることができる。導電性基材は剛性の基材であってもよく、可撓性の基材であってもよい。剛性の導電性基材としては、例えば、上記各金属の箔、板等、エキスパンドメタル、パンチドメタル等を挙げることができ、可撓性の導電性基材としては、例えば金属ワイヤーで織った（又は編んだ）金網等を挙げることができる。本発明の酸素発生反応用触媒の導電性基材への担持方法及び担持量は、本発明の酸素発生反応用触媒が電解液と接触でき触媒としての働きができれば特に制限されず、例えば担持方法としては、導電性基材の表面の全部又は一部に本発明の酸素発生反応用触媒をバインダー等を使用して付着させる方法、機械的に接触させる方法等を挙げることができる。本発明における陰極としては、電解の電極に使用可能な基材であれば特に制限されないが、通常、導電性基材と、前記基材の表面に担持されている触媒層とを備える。導電性基材としては、電解の電極に使用可能な基材であれば特に制限されず、例えば、ニッケル、ニッケル合金、ステンレススチール、軟鋼、又はステンレススチール若しくは軟鋼の表面にニッケルメッキを施したもの等を挙げることができる。導電性基材は、例えば剛性の基材であってもよく、可撓性の基材であってもよい。剛性の導電性基材としては、例えばエキスパンドメタル、パンチドメタル等を挙げることができ、可撓性の導電性基材としては、例えば金属ワイヤーで織った（又は編んだ）金網等を挙げることができる。陰極の触媒層としては、貴金属若しくは貴金属酸化物、ニッケル、コバルト、モリブデン若しくはマンガン、又はこれらの酸化物からなる触媒層等を挙げることができる。本発明における陽極室及び陰極室には、それぞれ上記陽極及び陰極が配置される。
The electrolytic cell of the present invention is an electrolytic cell comprising an anode chamber and a cathode chamber separated by an ion-permeable diaphragm, an anode disposed in the anode chamber, and a cathode disposed in the cathode chamber, and the anode is provided with the oxygen generating reaction catalyst of the present invention, which supports iron tungstate on the surface of a nickel porous body. The ion-permeable diaphragm in the present invention is not particularly limited as long as it is an ion-permeable diaphragm that can be used in an electrolytic cell for electrolysis of an aqueous solution or the like, and examples thereof include porous diaphragms such as porous membranes made of asbestos or modified asbestos, porous diaphragms using polysulfone-based polymers, cloth using polyphenylene sulfide fibers, fluorine-based porous membranes, porous membranes using hybrid materials containing both inorganic and organic materials, fluorine-based ion exchange membranes, and hydrocarbon-based ion exchange membranes. The ion-permeable diaphragm in the present invention preferably has low gas permeability, low electrical conductivity, and high strength. The oxygen generating reaction catalyst of the present invention supports iron tungstate on the surface of a nickel porous body such as a nickel mesh, and therefore the oxygen generating reaction catalyst of the present invention itself can be used as the anode. The oxygen generating reaction catalyst of the present invention may be further supported on a conductive substrate and used as an anode. Examples of the conductive substrate include nickel, nickel alloy, nickel iron, vanadium, molybdenum, copper, silver, manganese, platinum group elements, graphite, or chromium, or a combination thereof. The conductive substrate may be a rigid substrate or a flexible substrate. Examples of the rigid conductive substrate include foils, plates, and the like of the above metals, expanded metals, punched metals, and the like, and examples of the flexible conductive substrate include wire mesh woven (or knitted) with metal wires. The method and amount of the oxygen generating reaction catalyst of the present invention supported on the conductive substrate are not particularly limited as long as the oxygen generating reaction catalyst of the present invention can contact the electrolyte and function as a catalyst. For example, examples of the supporting method include a method in which the oxygen generating reaction catalyst of the present invention is attached to the entire or part of the surface of the conductive substrate using a binder, or a method in which the catalyst is mechanically contacted. The cathode in the present invention is not particularly limited as long as it is a substrate usable as an electrode for electrolysis, but usually includes a conductive substrate and a catalyst layer supported on the surface of the substrate. The conductive substrate is not particularly limited as long as it is a substrate usable as an electrode for electrolysis, and examples thereof include nickel, nickel alloy, stainless steel, mild steel, or stainless steel or mild steel with nickel plating on the surface. The conductive substrate may be, for example, a rigid substrate or a flexible substrate. Examples of rigid conductive substrates include expanded metal and punched metal, and examples of flexible conductive substrates include wire mesh woven (or knitted) with metal wires. Examples of the catalytic layer of the cathode include a catalytic layer made of a noble metal or a noble metal oxide, nickel, cobalt, molybdenum, or manganese, or an oxide thereof. The anode and cathode chambers in the present invention are respectively provided with the above-mentioned anode and cathode.
本発明の電解槽では、陽極室及び陰極室に電解質を含んだ水が供給されて電解され、陽極室では酸素が発生し、陰極室では水素が発生する。図１は、本発明の電解槽の構成を模式的に示した図である。アノード（陽極）は、本発明の酸素発生反応用触媒を備えている。隔膜の左側が陽極室であり、右側が陰極室であり、陽極室にはアノード（陽極）が配置され、陰極室にはカソード（陰極）が配置されている。図１では、アノード及びカソードがそれぞれ陽極室及び陰極室の端に配置されているが、端以外の位置、例えば中央付近等に配置されてもよく、例えば、ゼロギャップ型電解槽と同様の配置でもよい。本発明の電解槽を用いて、陽極室にアルカリを含む水を供給し、陰極室に塩水を供給して塩水を電解することができる。本発明の電解槽を用いて、陽極室にアルカリを含む塩水を供給し、陰極室に塩水を供給して塩水を電解することができ、例えば、陽極室には、ＮａＣｌとＫＯＨを含む水が供給され、陰極室にはＮａＣｌを含む水が供給される。ここで、アルカリとは、水に溶解して塩基性を示す化合物のことであり、例えば、アルカリ金属の水酸化物、アルカリ土類金属の水酸化物等を挙げることができる。図１では、アルカリとしてＫＯＨを使用した例を示しているが、ＫＯＨ以外にも、例えばＮａＯＨ、ＬｉＯＨ、ＣｓＯＨ等を使用することができる。また、塩水とはＮａＣｌを含む水溶液をいう。本発明において、アルカリを含む水とは、アルカリを含む塩水及びＮａＣｌを含まずアルカリを含む水を含み、塩水とは、アルカリを含まない塩水及びアルカリを含む塩水を含む。さらに、本発明の電解槽を用いて、陽極室にアルカリを含む水を供給し、陰極室にＮａＣｌを含まずアルカリを含む水を供給して、アルカリを含む水を電解することができる。本発明の電解槽は、陽極室と陰極室にＮａＣｌを含まずアルカリを含む水を供給して、供給された水を電解するアルカリ水電解を行うこともでき、上述のようにＮａＣｌとアルカリを含む水を陽極室と陰極室の少なくとも一方に供給して、供給された水を電解するアルカリ塩水電解を行うこともできる。本発明の電解槽において、隔膜は陰イオン透過性の膜であり、ＯＨ－が陰極室から陽極室に移動する。アノード付近では酸素が発生し、カソード付近では水素が発生する。
In the electrolytic cell of the present invention, water containing an electrolyte is supplied to the anode chamber and the cathode chamber and electrolyzed, oxygen is generated in the anode chamber, and hydrogen is generated in the cathode chamber. FIG. 1 is a diagram showing a schematic configuration of the electrolytic cell of the present invention. The anode (positive electrode) is provided with the oxygen generating reaction catalyst of the present invention. The left side of the diaphragm is the anode chamber, and the right side is the cathode chamber, with the anode (positive electrode) disposed in the anode chamber and the cathode (negative electrode) disposed in the cathode chamber. In FIG. 1, the anode and the cathode are disposed at the ends of the anode chamber and the cathode chamber, respectively, but they may be disposed at positions other than the ends, for example, near the center, and may be disposed in the same manner as in a zero-gap electrolytic cell. Using the electrolytic cell of the present invention, alkali-containing water can be supplied to the anode chamber and salt water can be supplied to the cathode chamber to electrolyze salt water. Using the electrolytic cell of the present invention, salt water containing an alkali can be supplied to the anode chamber and salt water can be supplied to the cathode chamber to electrolyze salt water. For example, water containing NaCl and KOH is supplied to the anode chamber, and water containing NaCl is supplied to the cathode chamber. Here, the alkali refers to a compound that dissolves in water and exhibits basicity, and examples of such compounds include hydroxides of alkali metals and hydroxides of alkaline earth metals. FIG. 1 shows an example in which KOH is used as the alkali, but other than KOH, for example, NaOH, LiOH, CsOH, etc. can be used. Furthermore, salt water refers to an aqueous solution containing NaCl. In the present invention, water containing an alkali includes salt water containing an alkali and water containing an alkali without NaCl, and salt water includes salt water without an alkali and salt water containing an alkali. Furthermore, using the electrolytic cell of the present invention, water containing an alkali can be supplied to the anode chamber and water containing an alkali without NaCl is supplied to the cathode chamber to electrolyze water containing an alkali. The electrolytic cell of the present invention can perform alkaline water electrolysis by supplying water containing no NaCl but an alkali to the anode chamber and the cathode chamber and electrolyzing the supplied water, and can also perform alkaline salt water electrolysis by supplying water containing NaCl and an alkali to at least one of the anode chamber and the cathode chamber as described above and electrolyzing the supplied water. In the electrolytic cell of the present invention, the diaphragm is an anion-permeable membrane, and OH- moves from the cathode chamber to the anode chamber. Oxygen is generated near the anode, and hydrogen is generated near the cathode.
また、本発明の電解槽の他の形態としては、陽極室、隔膜及び陰極室に加えて、二酸化炭素を陰極に供給するためのガス拡散層を備え、二酸化炭素の還元を行ってもよい。図２は、このような電解槽の構成を模式的に示した図である。陽極は、本発明の酸素発生反応用触媒を備えている。図２では、陰極及び陰極表面にある二酸化炭素還元触媒と、アニオン交換膜により複合陰極を構成している。陰極の陽極と対向する側と反対側にガス拡散層が設けられ、このガス拡散層を通って二酸化炭素が陰極及び陰極上の触媒に達し、二酸化炭素が一酸化炭素に還元される。陽極室にはＫＯＨ水溶液が供給され、陽極付近で酸素が発生する。本実施形態においては、複合陰極が陰極室を兼ねている。本発明の電解槽により、アルカリ水を電解しながら二酸化炭素の電解による還元を行うアルカリ水ＣＯ２電解を行うことができる。また、本発明の電解槽の他の形態としては、陽極室、隔膜及び陰極室に加えて、陰極室の陽極室に対向する側の反対側に、二酸化炭素を陰極と接するように導入する二酸化炭素導入部を備え、前記二酸化炭素導入部において二酸化炭素の還元を行ってもよい。図３は、このような電解槽の構成を模式的に示した図である。図３では、隔膜の左側に陽極室が設けられ、右側に陰極室が設けられているが、陰極室の右側、すなわち陰極室の陽極室に対向する側の反対側に、二酸化炭素の導入部が設けられている。ここに導入された二酸化炭素は、カソードに接触して一酸化炭素に還元される。二酸化炭素導入部としては、カソードと二酸化炭素が接触するように二酸化炭素を導入できれば特に制限されず、例えば、二酸化炭素が流れる通路を設ける構造、ガス拡散層を設ける構造等を挙げることができる。陽極室には、ＮａＣｌとＮａＯＨを含んだ水が供給され、陰極室には、ＮａＣｌを含んだ水が供給されて、本発明の酸素発生反応用触媒を備えたアノード付近では酸素が発生し、カソード付近では水素が発生する。本発明の電解槽により、アルカリ塩水を電解しながら二酸化炭素の電解による還元を行うアルカリ塩水ＣＯ２電解を行うことができる。図２及び図３の電解槽及びこれらを使用した電解方法は、本発明の酸素発生反応用触媒の優れた酸素発生反応に対する活性を利用し、酸素発生反応による駆動力で反応系全体の活性を向上させて二酸化炭素還元反応を活性化するものである。以上、二酸化炭素を一酸化炭素に還元する例を一例として挙げたが、本発明はこれに限定されるものではない。例えば二酸化炭素を還元して生成される他の物質としては、ギ酸（ＨＣＯＯＨ）、メタン（ＣＨ４）、メタノール（ＣＨ３ＯＨ）、エタン（Ｃ２Ｈ６）、エチレン（Ｃ２Ｈ４）、エタノール（Ｃ２Ｈ５ＯＨ）、ホルムアルデヒド（ＨＣＨＯ）、アセトアルデヒド（ＣＨ３ＣＨＯ）、酢酸（ＣＨ３ＣＯＯＨ）エチレングルコール（ＨＯＣＨ２ＣＨ２ＯＨ）、１－プロパノール（ＣＨ３ＣＨ２ＣＨ２ＯＨ）等の炭素化合物が挙げられる。
In addition, as another embodiment of the electrolytic cell of the present invention, in addition to the anode chamber, the diaphragm, and the cathode chamber, a gas diffusion layer for supplying carbon dioxide to the cathode may be provided to perform carbon dioxide reduction. FIG. 2 is a diagram showing a schematic configuration of such an electrolytic cell. The anode is provided with the oxygen generation reaction catalyst of the present invention. In FIG. 2, a composite cathode is formed by the cathode, the carbon dioxide reduction catalyst on the cathode surface, and the anion exchange membrane. A gas diffusion layer is provided on the side of the cathode opposite to the side facing the anode, and carbon dioxide reaches the cathode and the catalyst on the cathode through this gas diffusion layer, and the carbon dioxide is reduced to carbon monoxide. A KOH aqueous solution is supplied to the anode chamber, and oxygen is generated near the anode. In this embodiment, the composite cathode also serves as the cathode chamber. The electrolytic cell of the present invention can perform alkaline water CO2 electrolysis in which alkaline water is electrolyzed while carbon dioxide is reduced by electrolysis. In addition, as another embodiment of the electrolytic cell of the present invention, in addition to the anode chamber, the diaphragm, and the cathode chamber, a carbon dioxide introduction part for introducing carbon dioxide so as to contact the cathode may be provided on the side of the cathode chamber opposite the anode chamber, and carbon dioxide reduction may be performed in the carbon dioxide introduction part. FIG. 3 is a diagram showing a schematic configuration of such an electrolytic cell. In FIG. 3, the anode chamber is provided on the left side of the diaphragm, and the cathode chamber is provided on the right side, and a carbon dioxide introduction part is provided on the right side of the cathode chamber, that is, on the side opposite the cathode chamber opposite the anode chamber. The carbon dioxide introduced here is reduced to carbon monoxide by contacting the cathode. The carbon dioxide introduction part is not particularly limited as long as it can introduce carbon dioxide so that the cathode and carbon dioxide come into contact with each other, and examples of the carbon dioxide introduction part include a structure having a passage through which carbon dioxide flows and a structure having a gas diffusion layer. Water containing NaCl and NaOH is supplied to the anode chamber, and water containing NaCl is supplied to the cathode chamber, and oxygen is generated near the anode equipped with the oxygen generation reaction catalyst of the present invention, and hydrogen is generated near the cathode. The electrolytic cell of the present invention can perform alkaline salt water CO2 electrolysis, which involves electrolytic reduction of carbon dioxide while electrolyzing alkaline salt water. The electrolytic cells of FIG. 2 and FIG. 3 and the electrolysis method using them utilize the excellent activity of the oxygen generating reaction catalyst of the present invention for the oxygen generating reaction, and improve the activity of the entire reaction system with the driving force of the oxygen generating reaction to activate the carbon dioxide reduction reaction. Although the example of reducing carbon dioxide to carbon monoxide has been given above, the present invention is not limited thereto. For example, other substances generated by reducing carbon dioxide include carbon compounds such as formic acid (HCOOH), methane (CH 4 ), methanol (CH 3 OH), ethane (C 2 H 6 ), ethylene (C 2 H 4 ), ethanol (C 2 H 5 OH), formaldehyde (HCHO), acetaldehyde (CH 3 CHO), acetic acid (CH 3 COOH), ethylene glycol (HOCH 2 CH 2 OH), and 1-propanol (CH 3 CH 2 CH 2 OH).
以下、本発明の実施例を挙げて、本発明を具体的に説明するが、本発明の技術的範囲はこれらの例示に限定されるものではない。
The present invention will be specifically explained below with reference to examples, but the technical scope of the present invention is not limited to these examples.
［実施例１］
１．２ｃｍ×１．２ｃｍに切ったニッケルメッシュ片を３ｍｏｌ／Ｌ ＨＣｌ溶液に浸漬して、１５分間超音波洗浄し、その後エタノールに浸漬して１５分間超音波洗浄し、次に水に浸漬して１５分間超音波洗浄した。ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、上記のように洗浄したニッケルメッシュを溶液中に浸漬させた。四口フラスコ中の溶液を７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸鉄（II）０．９７ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。冷却後、ニッケルメッシュを取り出し、蒸留水中で１分間超音波洗浄した。洗浄後、ニッケルメッシュを取り出し、乾燥して、表面にＦｅＷＯ４を担持したニッケルメッシュを得た。使用したニッケルメッシュ片（ＮＩ－３１８０３０、株式会社ニラコ）は、線径が０．１５ｍｍ、目開きが０．６９７ｍｍ、開口率が６７．７％であり、ニッケルの純度は９９％以上であった。実施例２～４並びに比較例３及び４においても、同じニッケルメッシュを使用した。使用したニッケルメッシュは、縦１ｃｍ×横１ｃｍの１ｃｍ２内に１辺が０．７５ｍｍの正方形の隙間が縦１２個、横１２個の合計１４４個存在していた。したがって、ニッケルメッシュの２次元投影面積は、１［ｃｍ２］－０．７５×１０－１［ｃｍ］×０．７５×１０－１［ｃｍ］×１４４［個］＝０．１９［ｃｍ２］となる。実施例１では、ニッケルメッシュの２次元投影面積あたりの質量は、処理前が１７８．３５ｍｇ／ｃｍ２、処理後が１８８．６７ｍｇ／ｃｍ２であったので、ニッケルメッシュの２次元投影面積あたりのＦｅＷＯ４の担持量は１０．３２ｍｇ／ｃｍ２であった。 [Example 1]
A nickel mesh piece cut to 1.2 cm x 1.2 cm was immersed in a 3 mol/L HCl solution and ultrasonically cleaned for 15 minutes, then immersed in ethanol and ultrasonically cleaned for 15 minutes, then immersed in water and ultrasonically cleaned for 15 minutes. 25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The pH-adjusted solution was transferred to a four-neck flask, and the nickel mesh washed as described above was immersed in the solution. After the solution in the four-neck flask was heated to 70°C, a solution of 0.97 g of iron acetate (II) and 1.67 g of sodium tungstate dihydrate dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220°C in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220°C for 1 hour while stirring vigorously. After refluxing, it was naturally cooled to room temperature. After cooling, the nickel mesh was taken out and ultrasonically cleaned in distilled water for 1 minute. After washing, the nickel mesh was taken out and dried to obtain a nickel mesh carrying FeWO 4 on its surface. The nickel mesh piece used (NI-318030, Nilaco Corporation) had a wire diameter of 0.15 mm, an opening of 0.697 mm, an aperture ratio of 67.7%, and a nickel purity of 99% or more. The same nickel mesh was used in Examples 2 to 4 and Comparative Examples 3 and 4. The nickel mesh used had 12 vertical and 12 horizontal square gaps with a side of 0.75 mm within an area of 1 cm 2 (length x width). Therefore, the two-dimensional projected area of the nickel mesh is 1 [cm 2 ] - 0.75 x 10 -1 [cm] x 0.75 x 10 -1 [cm] x 144 [pieces] = 0.19 [cm 2 ]. In Example 1, the mass per two-dimensional projected area of the nickel mesh was 178.35 mg/cm 2 before the treatment and 188.67 mg/cm 2 after the treatment, so the amount of FeWO 4 supported per two-dimensional projected area of the nickel mesh was 10.32 mg/cm 2 .
１．２ｃｍ×１．２ｃｍに切ったニッケルメッシュ片を３ｍｏｌ／Ｌ ＨＣｌ溶液に浸漬して、１５分間超音波洗浄し、その後エタノールに浸漬して１５分間超音波洗浄し、次に水に浸漬して１５分間超音波洗浄した。ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、上記のように洗浄したニッケルメッシュを溶液中に浸漬させた。四口フラスコ中の溶液を７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸鉄（II）０．９７ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。冷却後、ニッケルメッシュを取り出し、蒸留水中で１分間超音波洗浄した。洗浄後、ニッケルメッシュを取り出し、乾燥して、表面にＦｅＷＯ４を担持したニッケルメッシュを得た。使用したニッケルメッシュ片（ＮＩ－３１８０３０、株式会社ニラコ）は、線径が０．１５ｍｍ、目開きが０．６９７ｍｍ、開口率が６７．７％であり、ニッケルの純度は９９％以上であった。実施例２～４並びに比較例３及び４においても、同じニッケルメッシュを使用した。使用したニッケルメッシュは、縦１ｃｍ×横１ｃｍの１ｃｍ２内に１辺が０．７５ｍｍの正方形の隙間が縦１２個、横１２個の合計１４４個存在していた。したがって、ニッケルメッシュの２次元投影面積は、１［ｃｍ２］－０．７５×１０－１［ｃｍ］×０．７５×１０－１［ｃｍ］×１４４［個］＝０．１９［ｃｍ２］となる。実施例１では、ニッケルメッシュの２次元投影面積あたりの質量は、処理前が１７８．３５ｍｇ／ｃｍ２、処理後が１８８．６７ｍｇ／ｃｍ２であったので、ニッケルメッシュの２次元投影面積あたりのＦｅＷＯ４の担持量は１０．３２ｍｇ／ｃｍ２であった。 [Example 1]
A nickel mesh piece cut to 1.2 cm x 1.2 cm was immersed in a 3 mol/L HCl solution and ultrasonically cleaned for 15 minutes, then immersed in ethanol and ultrasonically cleaned for 15 minutes, then immersed in water and ultrasonically cleaned for 15 minutes. 25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The pH-adjusted solution was transferred to a four-neck flask, and the nickel mesh washed as described above was immersed in the solution. After the solution in the four-neck flask was heated to 70°C, a solution of 0.97 g of iron acetate (II) and 1.67 g of sodium tungstate dihydrate dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220°C in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220°C for 1 hour while stirring vigorously. After refluxing, it was naturally cooled to room temperature. After cooling, the nickel mesh was taken out and ultrasonically cleaned in distilled water for 1 minute. After washing, the nickel mesh was taken out and dried to obtain a nickel mesh carrying FeWO 4 on its surface. The nickel mesh piece used (NI-318030, Nilaco Corporation) had a wire diameter of 0.15 mm, an opening of 0.697 mm, an aperture ratio of 67.7%, and a nickel purity of 99% or more. The same nickel mesh was used in Examples 2 to 4 and Comparative Examples 3 and 4. The nickel mesh used had 12 vertical and 12 horizontal square gaps with a side of 0.75 mm within an area of 1 cm 2 (length x width). Therefore, the two-dimensional projected area of the nickel mesh is 1 [cm 2 ] - 0.75 x 10 -1 [cm] x 0.75 x 10 -1 [cm] x 144 [pieces] = 0.19 [cm 2 ]. In Example 1, the mass per two-dimensional projected area of the nickel mesh was 178.35 mg/cm 2 before the treatment and 188.67 mg/cm 2 after the treatment, so the amount of FeWO 4 supported per two-dimensional projected area of the nickel mesh was 10.32 mg/cm 2 .
［実施例２～４］
実施例２～４では、還流時間を変える以外は実施例１と同様にニッケルメッシュを処理して、表面にＦｅＷＯ４を担持したニッケルメッシュを得た。還流時間を実施例２では１５分、実施例３では３０分、実施例４では１８０分とした。実施例１と同様にＦｅＷＯ４の担持量を求めたところ、実施例２では２．２ｍｇ／ｃｍ２、実施例３では５．７９ｍｇ／ｃｍ２、実施例４では８．４６ｍｇ／ｃｍ２であった。 [Examples 2 to 4]
In Examples 2 to 4, nickel meshes were treated in the same manner as in Example 1, except that the reflux time was changed, to obtain nickel meshes carrying FeWO4 on their surfaces. The reflux time was 15 minutes in Example 2, 30 minutes in Example 3, and 180 minutes in Example 4. The amounts of FeWO4 carried were determined in the same manner as in Example 1, and were 2.2 mg/ cm2 in Example 2, 5.79 mg/ cm2 in Example 3, and 8.46 mg/ cm2 in Example 4.
実施例２～４では、還流時間を変える以外は実施例１と同様にニッケルメッシュを処理して、表面にＦｅＷＯ４を担持したニッケルメッシュを得た。還流時間を実施例２では１５分、実施例３では３０分、実施例４では１８０分とした。実施例１と同様にＦｅＷＯ４の担持量を求めたところ、実施例２では２．２ｍｇ／ｃｍ２、実施例３では５．７９ｍｇ／ｃｍ２、実施例４では８．４６ｍｇ／ｃｍ２であった。 [Examples 2 to 4]
In Examples 2 to 4, nickel meshes were treated in the same manner as in Example 1, except that the reflux time was changed, to obtain nickel meshes carrying FeWO4 on their surfaces. The reflux time was 15 minutes in Example 2, 30 minutes in Example 3, and 180 minutes in Example 4. The amounts of FeWO4 carried were determined in the same manner as in Example 1, and were 2.2 mg/ cm2 in Example 2, 5.79 mg/ cm2 in Example 3, and 8.46 mg/ cm2 in Example 4.
［比較例１］
ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸鉄（II）０．９７ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。得られた混合溶液に、酢酸とエタノールを加えて遠心分離を数回行った後、蒸留水のみを加えて遠心分離を数回行った。残滓を室温で５時間真空乾燥させることにより、鉄を組み込んだウォルフラマイト型タングステン酸化物（ＦｅＷＯ４）を得た。 [Comparative Example 1]
25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The solution after the pH adjustment was transferred to a four-neck flask, and after heating to 70° C., a solution of 0.97 g of iron acetate (II) and 1.67 g of sodium tungstate dihydrate dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220° C. in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220° C. for 1 hour while stirring vigorously. After refluxing, the solution was naturally cooled to room temperature. Acetic acid and ethanol were added to the obtained mixed solution and centrifuged several times, and then only distilled water was added and centrifuged several times. The residue was vacuum dried at room temperature for 5 hours to obtain wolframite-type tungsten oxide (FeWO 4 ) incorporating iron.
ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸鉄（II）０．９７ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。得られた混合溶液に、酢酸とエタノールを加えて遠心分離を数回行った後、蒸留水のみを加えて遠心分離を数回行った。残滓を室温で５時間真空乾燥させることにより、鉄を組み込んだウォルフラマイト型タングステン酸化物（ＦｅＷＯ４）を得た。 [Comparative Example 1]
25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The solution after the pH adjustment was transferred to a four-neck flask, and after heating to 70° C., a solution of 0.97 g of iron acetate (II) and 1.67 g of sodium tungstate dihydrate dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220° C. in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220° C. for 1 hour while stirring vigorously. After refluxing, the solution was naturally cooled to room temperature. Acetic acid and ethanol were added to the obtained mixed solution and centrifuged several times, and then only distilled water was added and centrifuged several times. The residue was vacuum dried at room temperature for 5 hours to obtain wolframite-type tungsten oxide (FeWO 4 ) incorporating iron.
［比較例２］
ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸ニッケル（II）四水和物１．２６ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。得られた混合溶液に、酢酸とエタノールを加えて遠心分離を数回行った後、蒸留水のみを加えて遠心分離を数回行った。残滓を室温で５時間真空乾燥させることにより、ニッケルを組み込んだウォルフラマイト型タングステン酸化物（ＮｉＷＯ４）を得た。 [Comparative Example 2]
25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The solution after the pH adjustment was transferred to a four-neck flask, and after heating to 70° C., a solution of 1.26 g of nickel acetate (II) tetrahydrate and 1.67 g of sodium tungstate dihydrate dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220° C. in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220° C. for 1 hour while stirring vigorously. After refluxing, the solution was naturally cooled to room temperature. Acetic acid and ethanol were added to the obtained mixed solution and centrifuged several times, and then only distilled water was added and centrifuged several times. The residue was vacuum dried at room temperature for 5 hours to obtain wolframite-type tungsten oxide (NiWO 4 ) incorporating nickel.
ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸ニッケル（II）四水和物１．２６ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。得られた混合溶液に、酢酸とエタノールを加えて遠心分離を数回行った後、蒸留水のみを加えて遠心分離を数回行った。残滓を室温で５時間真空乾燥させることにより、ニッケルを組み込んだウォルフラマイト型タングステン酸化物（ＮｉＷＯ４）を得た。 [Comparative Example 2]
25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The solution after the pH adjustment was transferred to a four-neck flask, and after heating to 70° C., a solution of 1.26 g of nickel acetate (II) tetrahydrate and 1.67 g of sodium tungstate dihydrate dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220° C. in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220° C. for 1 hour while stirring vigorously. After refluxing, the solution was naturally cooled to room temperature. Acetic acid and ethanol were added to the obtained mixed solution and centrifuged several times, and then only distilled water was added and centrifuged several times. The residue was vacuum dried at room temperature for 5 hours to obtain wolframite-type tungsten oxide (NiWO 4 ) incorporating nickel.
［比較例３］
１．２ｃｍ×１．２ｃｍに切ったニッケルメッシュ片を３ｍｏｌ／Ｌ ＨＣｌ溶液に浸漬して、１５分間超音波洗浄し、その後エタノールに浸漬して１５分間超音波洗浄し、次に水に浸漬して１５分間超音波洗浄した。ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、上記のように洗浄したニッケルメッシュを溶液中に浸漬させた。四口フラスコ中の溶液を７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸ニッケル（II）四水和物１．２６ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。冷却後、ニッケルメッシュを取り出し、蒸留水中で１分間超音波洗浄した。洗浄後、ニッケルメッシュを取り出し、乾燥して、表面にＮｉＷＯ４を担持したニッケルメッシュを得た。 [Comparative Example 3]
A nickel mesh piece cut to 1.2 cm x 1.2 cm was immersed in a 3 mol/L HCl solution and ultrasonically cleaned for 15 minutes, then immersed in ethanol and ultrasonically cleaned for 15 minutes, then immersed in water and ultrasonically cleaned for 15 minutes. 25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The pH-adjusted solution was transferred to a four-neck flask, and the nickel mesh washed as described above was immersed in the solution. After the solution in the four-neck flask was heated to 70°C, a solution in which 1.26 g of nickel acetate (II) tetrahydrate and 1.67 g of sodium tungstate dihydrate were dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220°C in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220°C for 1 hour while stirring vigorously. After refluxing, it was naturally cooled to room temperature. After cooling, the nickel mesh was taken out and ultrasonically cleaned in distilled water for 1 minute. After washing, the nickel mesh was taken out and dried to obtain a nickel mesh carrying NiWO4 on its surface.
１．２ｃｍ×１．２ｃｍに切ったニッケルメッシュ片を３ｍｏｌ／Ｌ ＨＣｌ溶液に浸漬して、１５分間超音波洗浄し、その後エタノールに浸漬して１５分間超音波洗浄し、次に水に浸漬して１５分間超音波洗浄した。ビーカーにジエチレングリコール２５ｍＬを入れ、蒸留水で希釈した塩酸によりｐＨ５．５に調整した。ｐＨ調整後の溶液を四口フラスコに移し、上記のように洗浄したニッケルメッシュを溶液中に浸漬させた。四口フラスコ中の溶液を７０℃まで昇温した後に、蒸留水２．５ｍＬに酢酸ニッケル（II）四水和物１．２６ｇとタングステン酸ナトリウム二水和物１．６７ｇを溶解した溶液を加え、撹拌子を用いて均一になるまで強く撹拌しながら、約４０分で２２０℃まで昇温した。その後、この溶液を強く撹拌しながら２２０℃で１時間還流した。還流後、室温まで自然冷却した。冷却後、ニッケルメッシュを取り出し、蒸留水中で１分間超音波洗浄した。洗浄後、ニッケルメッシュを取り出し、乾燥して、表面にＮｉＷＯ４を担持したニッケルメッシュを得た。 [Comparative Example 3]
A nickel mesh piece cut to 1.2 cm x 1.2 cm was immersed in a 3 mol/L HCl solution and ultrasonically cleaned for 15 minutes, then immersed in ethanol and ultrasonically cleaned for 15 minutes, then immersed in water and ultrasonically cleaned for 15 minutes. 25 mL of diethylene glycol was placed in a beaker, and the pH was adjusted to 5.5 with hydrochloric acid diluted with distilled water. The pH-adjusted solution was transferred to a four-neck flask, and the nickel mesh washed as described above was immersed in the solution. After the solution in the four-neck flask was heated to 70°C, a solution in which 1.26 g of nickel acetate (II) tetrahydrate and 1.67 g of sodium tungstate dihydrate were dissolved in 2.5 mL of distilled water was added, and the temperature was raised to 220°C in about 40 minutes while stirring vigorously with a stirrer until it became uniform. Then, the solution was refluxed at 220°C for 1 hour while stirring vigorously. After refluxing, it was naturally cooled to room temperature. After cooling, the nickel mesh was taken out and ultrasonically cleaned in distilled water for 1 minute. After washing, the nickel mesh was taken out and dried to obtain a nickel mesh carrying NiWO4 on its surface.
［比較例４］
１．２ｃｍ×１．２ｃｍに切ったニッケルメッシュ片を３ｍｏｌ／Ｌ ＨＣｌ溶液に浸漬して、１５分間超音波洗浄し、その後エタノールに浸漬して１５分間超音波洗浄し、次に水に浸漬して１５分間超音波洗浄した。 [Comparative Example 4]
A nickel mesh piece cut to 1.2 cm x 1.2 cm was immersed in a 3 mol/L HCl solution and ultrasonically cleaned for 15 minutes, then immersed in ethanol and ultrasonically cleaned for 15 minutes, and then immersed in water and ultrasonically cleaned for 15 minutes.
１．２ｃｍ×１．２ｃｍに切ったニッケルメッシュ片を３ｍｏｌ／Ｌ ＨＣｌ溶液に浸漬して、１５分間超音波洗浄し、その後エタノールに浸漬して１５分間超音波洗浄し、次に水に浸漬して１５分間超音波洗浄した。 [Comparative Example 4]
A nickel mesh piece cut to 1.2 cm x 1.2 cm was immersed in a 3 mol/L HCl solution and ultrasonically cleaned for 15 minutes, then immersed in ethanol and ultrasonically cleaned for 15 minutes, and then immersed in water and ultrasonically cleaned for 15 minutes.
［比較例５］
市販のＩｒＯ２（ＣＡＳ １２０３０－４９－８、純度９９．９％、ＳＴＲＥＭ社）を使用した。 [Comparative Example 5]
Commercially available IrO 2 (CAS 12030-49-8, purity 99.9%, STREM) was used.
市販のＩｒＯ２（ＣＡＳ １２０３０－４９－８、純度９９．９％、ＳＴＲＥＭ社）を使用した。 [Comparative Example 5]
Commercially available IrO 2 (CAS 12030-49-8, purity 99.9%, STREM) was used.
（ＳＥＭによる観察及びＥＤＳマッピング）
実施例１における処理後のニッケルメッシュをＳＥＭ（走査型電子顕微鏡）により観察し、さらにＥＤＳ（エネルギー分散型Ｘ線分光法）によるマッピングを行った。図４に、その結果を示す。図４の右上の画像は左上の画像のニッケルメッシュ表面を拡大した画像であり、左下の画像は右上の画像のニッケルメッシュ表面を更に拡大した画像である。右下は右上の部分のＥＤＳマッピング画像であり、Ｏと記載された画像は酸素元素の分布を赤色で示し、Ｆｅと記載された画像は鉄元素の分布を緑色で示し、Ｗと記載された画像はタングステン元素の分布を青色で示し、Ｎｉと記載された画像はニッケル元素の分布を赤紫色で示している。ＳＥＭ画像及びＥＤＳマッピングから、ニッケルメッシュの表面にＦｅ、Ｗ及びＯからなる化合物が均一に析出して、ニッケルメッシュ表面に担持されていることが分かる。 (SEM Observation and EDS Mapping)
The nickel mesh after the treatment in Example 1 was observed by SEM (scanning electron microscope), and further mapping was performed by EDS (energy dispersive X-ray spectroscopy). The results are shown in FIG. 4. The upper right image in FIG. 4 is an enlarged image of the nickel mesh surface of the upper left image, and the lower left image is an enlarged image of the nickel mesh surface of the upper right image. The lower right is an EDS mapping image of the upper right part, the image marked O shows the distribution of oxygen elements in red, the image marked Fe shows the distribution of iron elements in green, the image marked W shows the distribution of tungsten elements in blue, and the image marked Ni shows the distribution of nickel elements in reddish purple. From the SEM image and EDS mapping, it can be seen that a compound consisting of Fe, W, and O is uniformly precipitated on the surface of the nickel mesh and supported on the nickel mesh surface.
実施例１における処理後のニッケルメッシュをＳＥＭ（走査型電子顕微鏡）により観察し、さらにＥＤＳ（エネルギー分散型Ｘ線分光法）によるマッピングを行った。図４に、その結果を示す。図４の右上の画像は左上の画像のニッケルメッシュ表面を拡大した画像であり、左下の画像は右上の画像のニッケルメッシュ表面を更に拡大した画像である。右下は右上の部分のＥＤＳマッピング画像であり、Ｏと記載された画像は酸素元素の分布を赤色で示し、Ｆｅと記載された画像は鉄元素の分布を緑色で示し、Ｗと記載された画像はタングステン元素の分布を青色で示し、Ｎｉと記載された画像はニッケル元素の分布を赤紫色で示している。ＳＥＭ画像及びＥＤＳマッピングから、ニッケルメッシュの表面にＦｅ、Ｗ及びＯからなる化合物が均一に析出して、ニッケルメッシュ表面に担持されていることが分かる。 (SEM Observation and EDS Mapping)
The nickel mesh after the treatment in Example 1 was observed by SEM (scanning electron microscope), and further mapping was performed by EDS (energy dispersive X-ray spectroscopy). The results are shown in FIG. 4. The upper right image in FIG. 4 is an enlarged image of the nickel mesh surface of the upper left image, and the lower left image is an enlarged image of the nickel mesh surface of the upper right image. The lower right is an EDS mapping image of the upper right part, the image marked O shows the distribution of oxygen elements in red, the image marked Fe shows the distribution of iron elements in green, the image marked W shows the distribution of tungsten elements in blue, and the image marked Ni shows the distribution of nickel elements in reddish purple. From the SEM image and EDS mapping, it can be seen that a compound consisting of Fe, W, and O is uniformly precipitated on the surface of the nickel mesh and supported on the nickel mesh surface.
（Ｘ線回折（ＸＲＤ））
実施例１で得られた試料のＸＲＤパターンをＣｕＫα放射線（４０ｋｖ、４０ｍＡ）を備えたＸ線回折計（ＲｉｇａｋｕＵｌｔｉｍａ４）により測定した。また、比較のためにニッケル板、及びニッケルメッシュのかわりにニッケル板を実施例１と同様に処理した試料のＸＲＤパターンを測定した。結果を図５に示す。図５において、ＦｅＷＯ４＿ＮＭは実施例１で得られた試料の結果を示し、ＦｅＷＯ４＿Ｎｉ板は実施例１と同様に処理したニッケル板の結果を示し、Ｎｉ板はニッケル板の結果を示す。同様に、比較例１及び２で得られた試料のＸＲＤパターンを測定した。結果を図６に示す。図６の上側に示したのが比較例２の結果であり、図６の下側に示したのが比較例１の結果である。図６の結果から比較例１においてＦｅＷＯ４が得られ、比較例２においてＮｉＷＯ４が得られたことが分かる。比較例１の合成条件は実施例１と同じであることから、実施例１ではニッケルメッシュの表面にＦｅ、Ｗ及びＯからなる化合物としてＦｅＷＯ４が析出していることが分かる。また、比較例２の合成条件は比較例３と同じであることから、比較例３ではニッケルメッシュの表面にＮｉＷＯ４が析出していることが分かる。また、ニッケル板を実施例１と同様に処理したＦｅＷＯ４＿Ｎｉ板において、ＦｅＷＯ４の標準物質と同様のＸＲＤパターンが観察されたことからも（図５）、実施例１で処理したニッケルメッシュの表面にはＦｅＷＯ４が析出していることが分かる。図５におけるＦｅＷＯ４＿ＮＭのＸＲＤパターンに、ＦｅＷＯ４＿Ｎｉ板ほどＦｅＷＯ４のピークが明確に表れていないのは、ニッケルメッシュの表面に堆積したＦｅＷＯ４の量がニッケル板表面に堆積したＦｅＷＯ４の量より少なかったためと考えられる。 X-Ray Diffraction (XRD)
The XRD pattern of the sample obtained in Example 1 was measured by an X-ray diffractometer (Rigaku Ultima 4) equipped with CuKα radiation (40 kv, 40 mA). For comparison, the XRD patterns of a nickel plate and a sample in which a nickel plate was used instead of a nickel mesh and treated in the same manner as in Example 1 were measured. The results are shown in FIG. 5. In FIG. 5, FeWO 4 _ NM indicates the results of the sample obtained in Example 1, FeWO 4 _ Ni plate indicates the results of the nickel plate treated in the same manner as in Example 1, and Ni plate indicates the results of the nickel plate. Similarly, the XRD patterns of the samples obtained in Comparative Examples 1 and 2 were measured. The results are shown in FIG. 6. The upper side of FIG. 6 shows the results of Comparative Example 2, and the lower side of FIG. 6 shows the results of Comparative Example 1. It can be seen from the results in FIG. 6 that FeWO 4 was obtained in Comparative Example 1, and NiWO 4 was obtained in Comparative Example 2. Since the synthesis conditions of Comparative Example 1 are the same as those of Example 1, it can be seen that FeWO 4 is precipitated on the surface of the nickel mesh in Example 1 as a compound consisting of Fe, W and O. Also, since the synthesis conditions of Comparative Example 2 are the same as those of Comparative Example 3, it can be seen that NiWO 4 is precipitated on the surface of the nickel mesh in Comparative Example 3. Also, since the XRD pattern similar to that of the standard substance of FeWO 4 was observed in the FeWO 4 _ Ni plate obtained by treating the nickel plate in the same manner as in Example 1 (FIG. 5), it can be seen that FeWO 4 is precipitated on the surface of the nickel mesh treated in Example 1. The reason why the peak of FeWO 4 is not as clear in the XRD pattern of FeWO 4 _ NM in FIG. 5 is thought to be because the amount of FeWO 4 deposited on the surface of the nickel mesh was less than the amount of FeWO 4 deposited on the surface of the nickel plate.
実施例１で得られた試料のＸＲＤパターンをＣｕＫα放射線（４０ｋｖ、４０ｍＡ）を備えたＸ線回折計（ＲｉｇａｋｕＵｌｔｉｍａ４）により測定した。また、比較のためにニッケル板、及びニッケルメッシュのかわりにニッケル板を実施例１と同様に処理した試料のＸＲＤパターンを測定した。結果を図５に示す。図５において、ＦｅＷＯ４＿ＮＭは実施例１で得られた試料の結果を示し、ＦｅＷＯ４＿Ｎｉ板は実施例１と同様に処理したニッケル板の結果を示し、Ｎｉ板はニッケル板の結果を示す。同様に、比較例１及び２で得られた試料のＸＲＤパターンを測定した。結果を図６に示す。図６の上側に示したのが比較例２の結果であり、図６の下側に示したのが比較例１の結果である。図６の結果から比較例１においてＦｅＷＯ４が得られ、比較例２においてＮｉＷＯ４が得られたことが分かる。比較例１の合成条件は実施例１と同じであることから、実施例１ではニッケルメッシュの表面にＦｅ、Ｗ及びＯからなる化合物としてＦｅＷＯ４が析出していることが分かる。また、比較例２の合成条件は比較例３と同じであることから、比較例３ではニッケルメッシュの表面にＮｉＷＯ４が析出していることが分かる。また、ニッケル板を実施例１と同様に処理したＦｅＷＯ４＿Ｎｉ板において、ＦｅＷＯ４の標準物質と同様のＸＲＤパターンが観察されたことからも（図５）、実施例１で処理したニッケルメッシュの表面にはＦｅＷＯ４が析出していることが分かる。図５におけるＦｅＷＯ４＿ＮＭのＸＲＤパターンに、ＦｅＷＯ４＿Ｎｉ板ほどＦｅＷＯ４のピークが明確に表れていないのは、ニッケルメッシュの表面に堆積したＦｅＷＯ４の量がニッケル板表面に堆積したＦｅＷＯ４の量より少なかったためと考えられる。 X-Ray Diffraction (XRD)
The XRD pattern of the sample obtained in Example 1 was measured by an X-ray diffractometer (Rigaku Ultima 4) equipped with CuKα radiation (40 kv, 40 mA). For comparison, the XRD patterns of a nickel plate and a sample in which a nickel plate was used instead of a nickel mesh and treated in the same manner as in Example 1 were measured. The results are shown in FIG. 5. In FIG. 5, FeWO 4 _ NM indicates the results of the sample obtained in Example 1, FeWO 4 _ Ni plate indicates the results of the nickel plate treated in the same manner as in Example 1, and Ni plate indicates the results of the nickel plate. Similarly, the XRD patterns of the samples obtained in Comparative Examples 1 and 2 were measured. The results are shown in FIG. 6. The upper side of FIG. 6 shows the results of Comparative Example 2, and the lower side of FIG. 6 shows the results of Comparative Example 1. It can be seen from the results in FIG. 6 that FeWO 4 was obtained in Comparative Example 1, and NiWO 4 was obtained in Comparative Example 2. Since the synthesis conditions of Comparative Example 1 are the same as those of Example 1, it can be seen that FeWO 4 is precipitated on the surface of the nickel mesh in Example 1 as a compound consisting of Fe, W and O. Also, since the synthesis conditions of Comparative Example 2 are the same as those of Comparative Example 3, it can be seen that NiWO 4 is precipitated on the surface of the nickel mesh in Comparative Example 3. Also, since the XRD pattern similar to that of the standard substance of FeWO 4 was observed in the FeWO 4 _ Ni plate obtained by treating the nickel plate in the same manner as in Example 1 (FIG. 5), it can be seen that FeWO 4 is precipitated on the surface of the nickel mesh treated in Example 1. The reason why the peak of FeWO 4 is not as clear in the XRD pattern of FeWO 4 _ NM in FIG. 5 is thought to be because the amount of FeWO 4 deposited on the surface of the nickel mesh was less than the amount of FeWO 4 deposited on the surface of the nickel plate.
（リニアスイープボルタンメトリー）
実施例１で得られた表面にＦｅＷＯ４を担持したニッケルメッシュを電極として使用して、リニアスイープボルタンメトリーを行った。三電極セルを使用し、実施例１で得られた表面にＦｅＷＯ４を担持したニッケルメッシュを片面空きのテフロン製電極ホルダーに組み込んだものを作用極とした。作用極では、ニッケルメッシュがホルダーから縦１ｃｍ×横１ｃｍの範囲で露出していた。対極（対照電極）として白金メッシュを使用し、参照電極としてＨｇ／ＨｇＯ（１ＭＮａＯＨ）を使用した。作用極におけるＦｅＷＯ４を担持したニッケルメッシュの反応面積は０．１９ｃｍ２であった。ここで、反応面積とはニッケルメッシュの二次元投影面積で定義した。ニッケルメッシュの二次元投影面積とは、ニッケルメッシュを真上からみたときの空隙（開口）部を除いた二次元面積であり、実施例１と同様に求めた。電解液にはＮ２を３０分パージした１ＭＫＯＨを用いた。掃引速度を１ｍＶ／ｓとした。作用極と参照電極間に生じる溶液の抵抗は、フィードバック率６０％で補償された。実施例２～４で得られた表面にＦｅＷＯ４を担持したニッケルメッシュ、並びに比較例３で得られた表面にＮｉＷＯ４を担持したニッケルメッシュ及び比較例４の未処理のニッケルメッシュについても同様に試験した。比較例１で得られたＦｅＷＯ４については、エタノールを３５０μＬ、水を３５０μＬ、及びナフィオンを９５μＬ含む混合溶液に、比較例１で得られたＦｅＷＯ４試料を５ｍｇとアセチレンカーボンブラック（導電性カーボン）を５ｍｇ加え、５０分間超音波分散処理を行った。得られた分散液をアルミナで磨いたディスク電極（直径５ｍｍ、グラッシーカーボン製）に１０μＬ滴加した（活物質量：０．３２ｍｇ）。その後、ディスク電極を室温、空気中で乾燥させ、これを作用電極とした。三電極セルを使用し、対極（対照電極）として白金メッシュを使用し、参照電極としてＨｇ／ＨｇＯ（１ＭＮａＯＨ）を使用した。電解液にはＮ２を３０分パージした１ＭＫＯＨを用いた。掃引速度を１ｍＶ／ｓとし、作用極上の酸素気泡を取り除くため回転数を１６００ｒｐｍとした。作用極と参照電極間に生じる溶液の抵抗は、フィードバック率６０％で補償された。比較例１、２及び５で得られた試料についても同様に試験した。実施例１、比較例３及び４についての試験の場合、作用極上に発生する酸素気泡は電極上から効率的に除去されていることから、これらの試験では回転ディスク法の回転を必要としなかった。また、上記試験において、酸素発生反応ではプロトンが生じるため、電解液のｐＨが小さくなり、水酸化電位が変化する。可逆水素電極（ＲＨＥ）に変換することで、ｐＨの影響をキャンセルすることができる。変換には、ＥＲＨＥ＝０．０５９×１４＋０．１２３＋ＥＨｇ／ＨｇＯの式を用いた。ｐＨは１４であった。結果を図７及び図８に示す。 (Linear Sweep Voltammetry)
Linear sweep voltammetry was performed using the nickel mesh with FeWO 4 supported on its surface obtained in Example 1 as an electrode. A three-electrode cell was used, and the nickel mesh with FeWO 4 supported on its surface obtained in Example 1 was incorporated into a Teflon electrode holder with one side open to form a working electrode. In the working electrode, the nickel mesh was exposed from the holder in a range of 1 cm vertical x 1 cm horizontal. A platinum mesh was used as the counter electrode (reference electrode), and Hg/HgO (1M NaOH) was used as the reference electrode. The reaction area of the nickel mesh with FeWO 4 supported on the working electrode was 0.19 cm 2. Here, the reaction area was defined as the two-dimensional projected area of the nickel mesh. The two-dimensional projected area of the nickel mesh is the two-dimensional area excluding the voids (openings) when the nickel mesh is viewed from directly above, and was obtained in the same manner as in Example 1. 1M KOH purged with N 2 for 30 minutes was used as the electrolyte. The sweep rate was 1 mV/s. The resistance of the solution occurring between the working electrode and the reference electrode was compensated for by a feedback rate of 60%. The nickel meshes having FeWO 4 supported on the surface obtained in Examples 2 to 4, the nickel mesh having NiWO 4 supported on the surface obtained in Comparative Example 3, and the untreated nickel mesh of Comparative Example 4 were also tested in the same manner. For the FeWO 4 obtained in Comparative Example 1, 5 mg of the FeWO 4 sample obtained in Comparative Example 1 and 5 mg of acetylene carbon black (conductive carbon) were added to a mixed solution containing 350 μL of ethanol, 350 μL of water, and 95 μL of Nafion, and ultrasonic dispersion treatment was performed for 50 minutes. The obtained dispersion was dropped in 10 μL (active material amount: 0.32 mg) on a disk electrode (diameter 5 mm, made of glassy carbon) polished with alumina. The disk electrode was then dried in air at room temperature and used as the working electrode. A three-electrode cell was used, a platinum mesh was used as the counter electrode (reference electrode), and Hg/HgO (1M NaOH) was used as the reference electrode. The electrolyte used was 1M KOH purged with N2 for 30 minutes. The sweep rate was 1 mV/s, and the rotation speed was 1600 rpm to remove oxygen bubbles on the working electrode. The resistance of the solution between the working electrode and the reference electrode was compensated for by a feedback rate of 60%. The samples obtained in Comparative Examples 1, 2, and 5 were also tested in the same manner. In the tests for Example 1, Comparative Examples 3, and 4, the oxygen bubbles generated on the working electrode were efficiently removed from the electrode, so that these tests did not require rotation by the rotating disk method. In addition, in the above test, protons are generated in the oxygen generation reaction, so the pH of the electrolyte becomes smaller and the hydroxide potential changes. The effect of pH can be canceled by converting to a reversible hydrogen electrode (RHE). For the conversion, the formula E RHE = 0.059 × 14 + 0.123 + E Hg/HgO was used. The pH was 14. The results are shown in Figures 7 and 8.
実施例１で得られた表面にＦｅＷＯ４を担持したニッケルメッシュを電極として使用して、リニアスイープボルタンメトリーを行った。三電極セルを使用し、実施例１で得られた表面にＦｅＷＯ４を担持したニッケルメッシュを片面空きのテフロン製電極ホルダーに組み込んだものを作用極とした。作用極では、ニッケルメッシュがホルダーから縦１ｃｍ×横１ｃｍの範囲で露出していた。対極（対照電極）として白金メッシュを使用し、参照電極としてＨｇ／ＨｇＯ（１ＭＮａＯＨ）を使用した。作用極におけるＦｅＷＯ４を担持したニッケルメッシュの反応面積は０．１９ｃｍ２であった。ここで、反応面積とはニッケルメッシュの二次元投影面積で定義した。ニッケルメッシュの二次元投影面積とは、ニッケルメッシュを真上からみたときの空隙（開口）部を除いた二次元面積であり、実施例１と同様に求めた。電解液にはＮ２を３０分パージした１ＭＫＯＨを用いた。掃引速度を１ｍＶ／ｓとした。作用極と参照電極間に生じる溶液の抵抗は、フィードバック率６０％で補償された。実施例２～４で得られた表面にＦｅＷＯ４を担持したニッケルメッシュ、並びに比較例３で得られた表面にＮｉＷＯ４を担持したニッケルメッシュ及び比較例４の未処理のニッケルメッシュについても同様に試験した。比較例１で得られたＦｅＷＯ４については、エタノールを３５０μＬ、水を３５０μＬ、及びナフィオンを９５μＬ含む混合溶液に、比較例１で得られたＦｅＷＯ４試料を５ｍｇとアセチレンカーボンブラック（導電性カーボン）を５ｍｇ加え、５０分間超音波分散処理を行った。得られた分散液をアルミナで磨いたディスク電極（直径５ｍｍ、グラッシーカーボン製）に１０μＬ滴加した（活物質量：０．３２ｍｇ）。その後、ディスク電極を室温、空気中で乾燥させ、これを作用電極とした。三電極セルを使用し、対極（対照電極）として白金メッシュを使用し、参照電極としてＨｇ／ＨｇＯ（１ＭＮａＯＨ）を使用した。電解液にはＮ２を３０分パージした１ＭＫＯＨを用いた。掃引速度を１ｍＶ／ｓとし、作用極上の酸素気泡を取り除くため回転数を１６００ｒｐｍとした。作用極と参照電極間に生じる溶液の抵抗は、フィードバック率６０％で補償された。比較例１、２及び５で得られた試料についても同様に試験した。実施例１、比較例３及び４についての試験の場合、作用極上に発生する酸素気泡は電極上から効率的に除去されていることから、これらの試験では回転ディスク法の回転を必要としなかった。また、上記試験において、酸素発生反応ではプロトンが生じるため、電解液のｐＨが小さくなり、水酸化電位が変化する。可逆水素電極（ＲＨＥ）に変換することで、ｐＨの影響をキャンセルすることができる。変換には、ＥＲＨＥ＝０．０５９×１４＋０．１２３＋ＥＨｇ／ＨｇＯの式を用いた。ｐＨは１４であった。結果を図７及び図８に示す。 (Linear Sweep Voltammetry)
Linear sweep voltammetry was performed using the nickel mesh with FeWO 4 supported on its surface obtained in Example 1 as an electrode. A three-electrode cell was used, and the nickel mesh with FeWO 4 supported on its surface obtained in Example 1 was incorporated into a Teflon electrode holder with one side open to form a working electrode. In the working electrode, the nickel mesh was exposed from the holder in a range of 1 cm vertical x 1 cm horizontal. A platinum mesh was used as the counter electrode (reference electrode), and Hg/HgO (1M NaOH) was used as the reference electrode. The reaction area of the nickel mesh with FeWO 4 supported on the working electrode was 0.19 cm 2. Here, the reaction area was defined as the two-dimensional projected area of the nickel mesh. The two-dimensional projected area of the nickel mesh is the two-dimensional area excluding the voids (openings) when the nickel mesh is viewed from directly above, and was obtained in the same manner as in Example 1. 1M KOH purged with N 2 for 30 minutes was used as the electrolyte. The sweep rate was 1 mV/s. The resistance of the solution occurring between the working electrode and the reference electrode was compensated for by a feedback rate of 60%. The nickel meshes having FeWO 4 supported on the surface obtained in Examples 2 to 4, the nickel mesh having NiWO 4 supported on the surface obtained in Comparative Example 3, and the untreated nickel mesh of Comparative Example 4 were also tested in the same manner. For the FeWO 4 obtained in Comparative Example 1, 5 mg of the FeWO 4 sample obtained in Comparative Example 1 and 5 mg of acetylene carbon black (conductive carbon) were added to a mixed solution containing 350 μL of ethanol, 350 μL of water, and 95 μL of Nafion, and ultrasonic dispersion treatment was performed for 50 minutes. The obtained dispersion was dropped in 10 μL (active material amount: 0.32 mg) on a disk electrode (diameter 5 mm, made of glassy carbon) polished with alumina. The disk electrode was then dried in air at room temperature and used as the working electrode. A three-electrode cell was used, a platinum mesh was used as the counter electrode (reference electrode), and Hg/HgO (1M NaOH) was used as the reference electrode. The electrolyte used was 1M KOH purged with N2 for 30 minutes. The sweep rate was 1 mV/s, and the rotation speed was 1600 rpm to remove oxygen bubbles on the working electrode. The resistance of the solution between the working electrode and the reference electrode was compensated for by a feedback rate of 60%. The samples obtained in Comparative Examples 1, 2, and 5 were also tested in the same manner. In the tests for Example 1, Comparative Examples 3, and 4, the oxygen bubbles generated on the working electrode were efficiently removed from the electrode, so that these tests did not require rotation by the rotating disk method. In addition, in the above test, protons are generated in the oxygen generation reaction, so the pH of the electrolyte becomes smaller and the hydroxide potential changes. The effect of pH can be canceled by converting to a reversible hydrogen electrode (RHE). For the conversion, the formula E RHE = 0.059 × 14 + 0.123 + E Hg/HgO was used. The pH was 14. The results are shown in Figures 7 and 8.
図７から明らかなように、ＦｅＷＯ４を単に使用した比較例１では触媒活性がみられなかったのに対し、実施例１で得られた表面にＦｅＷＯ４を担持したニッケルメッシュでは、電流のシャープな立ち上がりが見られ、貴金属であるＩｒＯ２を使用した比較例５や表面にＮｉＷＯ４を担持したニッケルメッシュを使用した比較例３に比べても高い触媒活性を示した。また、図８から分かるように、還流時間を変えて調製した実施例２～４でも実施例１と同様の高い触媒活性を示した。
As is clear from Fig. 7, no catalytic activity was observed in Comparative Example 1 in which FeWO4 was simply used, whereas in the nickel mesh having FeWO4 supported on its surface obtained in Example 1, a sharp rise in current was observed, and a higher catalytic activity was observed than in Comparative Example 5 in which IrO2 , a noble metal, was used, and in Comparative Example 3 in which a nickel mesh having NiWO4 supported on its surface was used. Also, as can be seen from Fig. 8, Examples 2 to 4 prepared by changing the reflux time also showed high catalytic activity similar to that of Example 1.
図７及び図８の立ち上がり部分を解析するために、各図についてターフェルプロットを作成した。図７及び図８とプロットより算出されたパラメータ（開始過電圧はプロットの直線領域の低電位側の端点と定義）を表１に示す。ターフェル勾配はプロットと直線の重複部分から算出され、ターフェル式［η＝ａ＋ｂ・ｌｏｇ（ｊ）］により近似された。ここで、ａはターフェル定数、ｂはターフェル勾配、ｊは電流密度である。表１から、実施例１で得られたＦｅＷＯ４を担持したニッケルメッシュは、ＩｒＯ２（比較例５）に匹敵する開始過電圧を示し、電流密度１０ｍＡ／ｃｍ２時の過電圧はＩｒＯ２（比較例５）に比べて低い。さらに、ターフェル勾配も、ＩｒＯ２（比較例５）に比べて小さい。ターフェル勾配は、電流値が１０倍になるのに要する電位差であり、値が小さいほど反応速度が速く、活性であることを表し、水酸化における電子移動の速さを表す。表１の結果は、実施例１で得られたＦｅＷＯ４を担持したニッケルメッシュは、ＩｒＯ２（比較例５）及び他の比較例で得られた試料よりも反応速度が著しく速いことを示している。表２から、還流時間を変えて得られた実施例２～４のＦｅＷＯ４を担持したニッケルメッシュも、実施例１と同様の開始過電圧、電流密度１０ｍＡ／ｃｍ２時の過電圧及びターフェル勾配を有することが分かった。表２におけるη１０は１０ｍＡ／ｃｍ２時の過電圧を表し、η１００は１００ｍＡ／ｃｍ２時の過電圧を表し、η５００は５００ｍＡ／ｃｍ２時の過電圧を表す。
In order to analyze the rising parts of Fig. 7 and Fig. 8, Tafel plots were created for each figure. Table 1 shows Fig. 7 and Fig. 8 and the parameters calculated from the plots (initial overvoltage is defined as the low potential end point of the linear region of the plot). The Tafel slope was calculated from the overlapping part of the plot and the straight line, and was approximated by the Tafel formula [η = a + b log (j)]. Here, a is the Tafel constant, b is the Tafel slope, and j is the current density. From Table 1, the nickel mesh carrying FeWO 4 obtained in Example 1 shows an initial overvoltage comparable to IrO 2 (Comparative Example 5), and the overvoltage at a current density of 10 mA / cm 2 is lower than that of IrO 2 (Comparative Example 5). Furthermore, the Tafel slope is also smaller than that of IrO 2 (Comparative Example 5). The Tafel slope is the potential difference required for the current value to become 10 times, and the smaller the value, the faster the reaction rate and the more active it is, and it represents the speed of electron transfer in hydroxylation. The results in Table 1 show that the nickel mesh carrying FeWO 4 obtained in Example 1 has a significantly faster reaction rate than IrO 2 (Comparative Example 5) and the samples obtained in other Comparative Examples. From Table 2, it was found that the nickel mesh carrying FeWO 4 in Examples 2 to 4 obtained by changing the reflux time also have the same initial overvoltage, overvoltage at a current density of 10 mA/cm 2 , and Tafel slope as in Example 1. In Table 2, η 10 represents the overvoltage at 10 mA/cm 2 , η 100 represents the overvoltage at 100 mA/cm 2 , and η 500 represents the overvoltage at 500 mA/cm 2 .
本発明の酸素発生反応用触媒は、優れた触媒活性を有するため、陽極又は正極に用いることができ、電気分解（電解）、電池等における酸素発生反応のための触媒として好適に使用でき、例えば、水の電気分解における陽極、金属空気電池における空気極（正極）、二酸化炭素の電解における還元反応の対極等に使用できる。
The oxygen generation reaction catalyst of the present invention has excellent catalytic activity and can be used as an anode or a cathode, and can be suitably used as a catalyst for the oxygen generation reaction in electrolysis (electrolysis), batteries, etc., and can be used, for example, as an anode in water electrolysis, an air electrode (cathode) in a metal-air battery, or a counter electrode in the reduction reaction in carbon dioxide electrolysis.
The oxygen generation reaction catalyst of the present invention has excellent catalytic activity and can be used as an anode or a cathode, and can be suitably used as a catalyst for the oxygen generation reaction in electrolysis (electrolysis), batteries, etc., and can be used, for example, as an anode in water electrolysis, an air electrode (cathode) in a metal-air battery, or a counter electrode in the reduction reaction in carbon dioxide electrolysis.
Claims (13)
- ニッケル多孔体の表面にタングステン酸鉄を担持した酸素発生反応用触媒。 A catalyst for oxygen generation reactions that supports iron tungstate on the surface of a porous nickel body.
- ニッケル多孔体がニッケルメッシュであることを特徴とする請求項１記載の酸素発生反応用触媒。 The catalyst for oxygen generation reaction according to claim 1, characterized in that the nickel porous body is a nickel mesh.
- ニッケル多孔体の存在下でタングステン酸鉄を合成して前記ニッケル多孔体の表面に前記タングステン酸鉄を担持させる酸素発生反応用触媒の製造方法であって、
前記タングステン酸鉄の合成が、タングステン酸塩及び鉄塩をポリオールに溶解させ、前記タングステン酸塩及び鉄塩が溶解したポリオール溶液を加熱することにより行われる、又はタングステン酸塩、鉄塩及び水を耐圧容器中に投入して加熱することにより行われる酸素発生反応用触媒の製造方法。 A method for producing a catalyst for oxygen generation reaction, comprising synthesizing iron tungstate in the presence of a nickel porous body and supporting the iron tungstate on a surface of the nickel porous body, comprising:
The synthesis of the iron tungstate is carried out by dissolving a tungstate and an iron salt in a polyol and heating the polyol solution in which the tungstate and the iron salt are dissolved, or by putting a tungstate, an iron salt and water into a pressure-resistant container and heating the container. - ニッケル多孔体がニッケルメッシュであることを特徴とする請求項３記載の酸素発生反応用触媒の製造方法。 The method for producing a catalyst for oxygen generation reaction according to claim 3, characterized in that the nickel porous body is a nickel mesh.
- イオン透過性の隔膜によって区画された陽極室及び陰極室を備え、前記陽極室に陽極が配置され、前記陰極室に陰極が配置された電解槽であって、前記陽極がニッケル多孔体の表面にタングステン酸鉄を担持した酸素発生反応用触媒を備えた電解槽。 An electrolytic cell having an anode chamber and a cathode chamber separated by an ion-permeable diaphragm, an anode disposed in the anode chamber, and a cathode disposed in the cathode chamber, the anode being provided with a catalyst for oxygen generation reaction in the form of iron tungstate supported on the surface of a nickel porous body.
- 二酸化炭素を陰極に供給するためのガス拡散層を備え、陰極室において二酸化炭素の還元を行う請求項５記載の電解槽。 The electrolytic cell according to claim 5, which is provided with a gas diffusion layer for supplying carbon dioxide to the cathode and performs reduction of carbon dioxide in the cathode chamber.
- 陰極室の陽極室に対向する側の反対側に、二酸化炭素を陰極と接するように導入する二酸化炭素導入部を備え、前記二酸化炭素導入部において二酸化炭素の還元を行う請求項５記載の電解槽。 The electrolytic cell according to claim 5, further comprising a carbon dioxide introduction section for introducing carbon dioxide so as to come into contact with the cathode on the side of the cathode chamber opposite the anode chamber, and in which reduction of carbon dioxide is carried out in the carbon dioxide introduction section.
- 請求項５記載の電解槽における陽極室にアルカリを含む水を供給し、陰極室に塩水を供給して塩水を電解する塩水の電解方法。 A method for electrolyzing salt water by supplying alkaline water to the anode chamber of the electrolytic cell described in claim 5 and supplying salt water to the cathode chamber.
- 陽極室に供給するアルカリを含む水が、アルカリを含む塩水である請求項８記載の塩水の電解方法。 The method for electrolyzing salt water according to claim 8, wherein the alkali-containing water supplied to the anode chamber is salt water containing alkali.
- 陰極室に供給する塩水が、アルカリを含む塩水である請求項８又は９記載の塩水の電解方法。 The method for electrolyzing salt water according to claim 8 or 9, wherein the salt water supplied to the cathode chamber is salt water containing an alkali.
- 請求項５記載の電解槽における陽極室にアルカリを含む水を供給し、陰極室にＮａＣｌを含まずアルカリを含む水を供給して、アルカリを含む水を電解するアルカリを含む水の電解方法。 A method for electrolyzing alkaline water by supplying alkaline water to the anode chamber of the electrolytic cell described in claim 5 and supplying alkaline water but not NaCl to the cathode chamber.
- 陽極室に供給するアルカリを含む水が、ＮａＣｌを含まずアルカリを含む水である請求項１１記載のアルカリを含む水の電解方法。 The method for electrolyzing alkaline water according to claim 11, wherein the alkaline water supplied to the anode chamber is alkaline water that does not contain NaCl.
- 請求項７記載の電解槽における陽極室にアルカリを含む塩水を供給し、陰極室に塩水を供給し、二酸化炭素導入部に二酸化炭素を導入して、塩水を電解すると共に二酸化炭素の還元を行う塩水の電解及び二酸化炭素の還元方法。
A method for electrolyzing salt water and reducing carbon dioxide, comprising the steps of: supplying salt water containing an alkali to the anode chamber of the electrolytic cell according to claim 7; supplying salt water to the cathode chamber; and introducing carbon dioxide into the carbon dioxide inlet, thereby electrolyzing the salt water and reducing the carbon dioxide.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003527735A (en) * | 2000-03-22 | 2003-09-16 | スーペリア マイクロパウダーズ リミテッド ライアビリティ カンパニー | Electrode catalyst powder, method for producing powder, and device formed from the powder |
| JP2021070864A (en) * | 2019-11-01 | 2021-05-06 | 時空化学株式会社 | Electrode catalyst, method for producing the same, and method for producing hydrogen |
| JP2021186750A (en) * | 2020-05-29 | 2021-12-13 | 国立大学法人山口大学 | Catalyst for oxygen evolution reaction and method for producing the same |
| WO2022080256A1 (en) * | 2020-10-15 | 2022-04-21 | 国立大学法人山口大学 | Tungsten oxide and oxygen evolution reaction catalyst |
| JP2022167439A (en) * | 2021-04-23 | 2022-11-04 | 株式会社豊田中央研究所 | Membrane electrode assembly and manufacturing method thereof |
-
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- 2023-12-25 WO PCT/JP2023/046304 patent/WO2024143238A1/en unknown
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003527735A (en) * | 2000-03-22 | 2003-09-16 | スーペリア マイクロパウダーズ リミテッド ライアビリティ カンパニー | Electrode catalyst powder, method for producing powder, and device formed from the powder |
| JP2021070864A (en) * | 2019-11-01 | 2021-05-06 | 時空化学株式会社 | Electrode catalyst, method for producing the same, and method for producing hydrogen |
| JP2021186750A (en) * | 2020-05-29 | 2021-12-13 | 国立大学法人山口大学 | Catalyst for oxygen evolution reaction and method for producing the same |
| WO2022080256A1 (en) * | 2020-10-15 | 2022-04-21 | 国立大学法人山口大学 | Tungsten oxide and oxygen evolution reaction catalyst |
| JP2022167439A (en) * | 2021-04-23 | 2022-11-04 | 株式会社豊田中央研究所 | Membrane electrode assembly and manufacturing method thereof |
Non-Patent Citations (1)
| Title |
|---|
| LUO WENJING, WANG JIAXIN, HU JUN, JI YUANCHUN, STREB CARSTEN, SONG YU‐FEI: "Composite Metal Oxide‐Carbon Nanotube Electrocatalysts for the Oxygen Evolution and Oxygen Reduction Reactions", CHEMELECTROCHEM, WILEY, CHICHESTER, vol. 5, no. 19, 1 October 2018 (2018-10-01), Chichester , pages 2850 - 2856, XP093185982, ISSN: 2196-0216, DOI: 10.1002/celc.201800680 * |
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