JP5121290B2 - Catalyst for polymer electrolyte fuel cell electrode - Google Patents
Catalyst for polymer electrolyte fuel cell electrode Download PDFInfo
- Publication number
- JP5121290B2 JP5121290B2 JP2007108547A JP2007108547A JP5121290B2 JP 5121290 B2 JP5121290 B2 JP 5121290B2 JP 2007108547 A JP2007108547 A JP 2007108547A JP 2007108547 A JP2007108547 A JP 2007108547A JP 5121290 B2 JP5121290 B2 JP 5121290B2
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- carbon
- carbon material
- functional group
- bet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000003054 catalyst Substances 0.000 title claims description 75
- 239000000446 fuel Substances 0.000 title claims description 45
- 239000005518 polymer electrolyte Substances 0.000 title claims description 34
- 239000003575 carbonaceous material Substances 0.000 claims description 70
- 125000000524 functional group Chemical group 0.000 claims description 70
- 229910052751 metal Inorganic materials 0.000 claims description 58
- 239000002184 metal Substances 0.000 claims description 56
- 239000010419 fine particle Substances 0.000 claims description 51
- 230000002378 acidificating effect Effects 0.000 claims description 28
- 239000011148 porous material Substances 0.000 claims description 21
- 238000001179 sorption measurement Methods 0.000 claims description 16
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 14
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 90
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 72
- 229910052799 carbon Inorganic materials 0.000 description 57
- 229910052697 platinum Inorganic materials 0.000 description 44
- 230000000694 effects Effects 0.000 description 32
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 27
- 239000006229 carbon black Substances 0.000 description 26
- 235000019241 carbon black Nutrition 0.000 description 26
- 239000007789 gas Substances 0.000 description 23
- 238000000034 method Methods 0.000 description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 19
- 238000006243 chemical reaction Methods 0.000 description 19
- 239000001301 oxygen Substances 0.000 description 18
- 229910052760 oxygen Inorganic materials 0.000 description 18
- 239000007787 solid Substances 0.000 description 18
- 239000002245 particle Substances 0.000 description 14
- 239000000243 solution Substances 0.000 description 14
- 230000003197 catalytic effect Effects 0.000 description 13
- 238000007254 oxidation reaction Methods 0.000 description 11
- 229920000642 polymer Polymers 0.000 description 10
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 230000006872 improvement Effects 0.000 description 9
- 230000003647 oxidation Effects 0.000 description 9
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 230000004913 activation Effects 0.000 description 8
- 229910045601 alloy Inorganic materials 0.000 description 8
- 239000000956 alloy Substances 0.000 description 8
- 239000006185 dispersion Substances 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 229910052739 hydrogen Inorganic materials 0.000 description 8
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 8
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 8
- 230000001965 increasing effect Effects 0.000 description 8
- 230000003993 interaction Effects 0.000 description 8
- 239000012528 membrane Substances 0.000 description 8
- 239000002002 slurry Substances 0.000 description 8
- 238000009792 diffusion process Methods 0.000 description 7
- 238000006722 reduction reaction Methods 0.000 description 7
- 229920005989 resin Polymers 0.000 description 7
- 239000011347 resin Substances 0.000 description 7
- 125000003277 amino group Chemical group 0.000 description 6
- 239000012298 atmosphere Substances 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 238000003487 electrochemical reaction Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 230000035699 permeability Effects 0.000 description 6
- 239000012071 phase Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 5
- 239000003792 electrolyte Substances 0.000 description 5
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 description 5
- 238000011068 loading method Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000002243 precursor Substances 0.000 description 5
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 229920000557 Nafion® Polymers 0.000 description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 229910052786 argon Inorganic materials 0.000 description 4
- 238000010828 elution Methods 0.000 description 4
- -1 hydrogen cations Chemical class 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 229910017604 nitric acid Inorganic materials 0.000 description 4
- 229910000510 noble metal Inorganic materials 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 238000005507 spraying Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 3
- 102000004310 Ion Channels Human genes 0.000 description 3
- 238000005275 alloying Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 3
- 239000003638 chemical reducing agent Substances 0.000 description 3
- 229920001940 conductive polymer Polymers 0.000 description 3
- 229910001873 dinitrogen Inorganic materials 0.000 description 3
- 238000010494 dissociation reaction Methods 0.000 description 3
- 230000005593 dissociations Effects 0.000 description 3
- 239000012153 distilled water Substances 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 229910021389 graphene Inorganic materials 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 231100000572 poisoning Toxicity 0.000 description 3
- 230000000607 poisoning effect Effects 0.000 description 3
- 125000004151 quinonyl group Chemical group 0.000 description 3
- 229910052707 ruthenium Inorganic materials 0.000 description 3
- 229910000077 silane Inorganic materials 0.000 description 3
- 125000000542 sulfonic acid group Chemical group 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical group OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 2
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 239000004809 Teflon Substances 0.000 description 2
- 229920006362 Teflon® Polymers 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 125000003118 aryl group Chemical group 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 150000004292 cyclic ethers Chemical class 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000010411 electrocatalyst Substances 0.000 description 2
- 239000002001 electrolyte material Substances 0.000 description 2
- 150000002170 ethers Chemical class 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 description 2
- 150000002431 hydrogen Chemical group 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 229920000554 ionomer Polymers 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- 239000006233 lamp black Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 238000009832 plasma treatment Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000027756 respiratory electron transport chain Effects 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000007784 solid electrolyte Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000012756 surface treatment agent Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- POILWHVDKZOXJZ-ARJAWSKDSA-M (z)-4-oxopent-2-en-2-olate Chemical compound C\C([O-])=C\C(C)=O POILWHVDKZOXJZ-ARJAWSKDSA-M 0.000 description 1
- VALXVSHDOMUUIC-UHFFFAOYSA-N 2-methylprop-2-enoic acid;phosphoric acid Chemical compound OP(O)(O)=O.CC(=C)C(O)=O VALXVSHDOMUUIC-UHFFFAOYSA-N 0.000 description 1
- NZEDMAWEJPYWCD-UHFFFAOYSA-N 3-prop-2-enylsulfonylprop-1-ene Chemical compound C=CCS(=O)(=O)CC=C NZEDMAWEJPYWCD-UHFFFAOYSA-N 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 229910001260 Pt alloy Inorganic materials 0.000 description 1
- 229910002839 Pt-Mo Inorganic materials 0.000 description 1
- 229910002849 PtRu Inorganic materials 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000003172 aldehyde group Chemical group 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- DLGYNVMUCSTYDQ-UHFFFAOYSA-N azane;pyridine Chemical compound N.C1=CC=NC=C1 DLGYNVMUCSTYDQ-UHFFFAOYSA-N 0.000 description 1
- 150000007514 bases Chemical class 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- SRSXLGNVWSONIS-UHFFFAOYSA-N benzenesulfonic acid Chemical compound OS(=O)(=O)C1=CC=CC=C1 SRSXLGNVWSONIS-UHFFFAOYSA-N 0.000 description 1
- 229940092714 benzenesulfonic acid Drugs 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- UORVGPXVDQYIDP-UHFFFAOYSA-N borane Chemical compound B UORVGPXVDQYIDP-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 229910010277 boron hydride Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000002134 carbon nanofiber Substances 0.000 description 1
- 238000010000 carbonizing Methods 0.000 description 1
- 150000001244 carboxylic acid anhydrides Chemical group 0.000 description 1
- 125000002843 carboxylic acid group Chemical group 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 235000015165 citric acid Nutrition 0.000 description 1
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid group Chemical class C(CC(O)(C(=O)O)CC(=O)O)(=O)O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 238000004040 coloring Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000003411 electrode reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- NLVXSWCKKBEXTG-UHFFFAOYSA-M ethenesulfonate Chemical compound [O-]S(=O)(=O)C=C NLVXSWCKKBEXTG-UHFFFAOYSA-M 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- UQSQSQZYBQSBJZ-UHFFFAOYSA-N fluorosulfonic acid Chemical compound OS(F)(=O)=O UQSQSQZYBQSBJZ-UHFFFAOYSA-N 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 239000006232 furnace black Substances 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 125000000686 lactone group Chemical group 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910001510 metal chloride Inorganic materials 0.000 description 1
- 229910001960 metal nitrate Inorganic materials 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000005395 methacrylic acid group Chemical group 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 239000002048 multi walled nanotube Substances 0.000 description 1
- SWVGZFQJXVPIKM-UHFFFAOYSA-N n,n-bis(methylamino)propan-1-amine Chemical compound CCCN(NC)NC SWVGZFQJXVPIKM-UHFFFAOYSA-N 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 150000002989 phenols Chemical class 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 125000003367 polycyclic group Chemical group 0.000 description 1
- 230000000379 polymerizing effect Effects 0.000 description 1
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 1
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 1
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000003223 protective agent Substances 0.000 description 1
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 1
- 235000011835 quiches Nutrition 0.000 description 1
- 229910052702 rhenium Inorganic materials 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 230000009291 secondary effect Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000002109 single walled nanotube Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000010189 synthetic method Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000009279 wet oxidation reaction Methods 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
Classifications
-
- 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
- Y02E60/50—Fuel cells
Landscapes
- Catalysts (AREA)
- Inert Electrodes (AREA)
- Fuel Cell (AREA)
Description
本発明は、固体高分子形燃料電池電極用触媒に関するものである。 The present invention relates to a catalyst for a polymer electrolyte fuel cell electrode.
固体高分子形燃料電池は、水素を燃料とするクリーンな電源として、電気自動車の駆動電源、また、発電と熱供給を併用する定置電源として開発が進められている。また、固体高分子形燃料電池は、リチウムイオン電池など二次電池と比較して高いエネルギー密度が特徴であり、携帯用コンピュータあるいは移動用通信機器の電源としても開発が進められている。 The polymer electrolyte fuel cell is being developed as a clean power source using hydrogen as a fuel, a driving power source for an electric vehicle, and a stationary power source using both power generation and heat supply. In addition, solid polymer fuel cells are characterized by high energy density compared to secondary batteries such as lithium ion batteries, and are being developed as power sources for portable computers or mobile communication devices.
固体高分子形燃料電池の発電部分（セル）は、アノード（燃料極）とカソード（空気極）、および両極間に配したプロトン伝導性の固体高分子電解質膜で構成される。アノードおよびカソードは、通常、白金などの貴金属を担持した触媒、フッ素樹脂紛などの造孔剤、および固体高分子電解質の混合体薄膜である。 The power generation portion (cell) of the solid polymer fuel cell is composed of an anode (fuel electrode) and a cathode (air electrode), and a proton-conducting solid polymer electrolyte membrane disposed between the two electrodes. The anode and the cathode are usually a mixed thin film of a catalyst supporting a noble metal such as platinum, a pore forming agent such as a fluororesin powder, and a solid polymer electrolyte.
固体高分子形燃料電池では、単位電極面積当たりの出力が高いことが求められる。最も効果的な前記解決策の一つは、アノードとカソードを構成する電極触媒で起こる電気化学反応の触媒活性を向上させることである。ここで、アノードでの電気化学反応は、水素を燃料とする反応であって、水素分子（Ｈ2）が水素カチオン（Ｈ+、プロトン）に酸化する電気化学的反応であり、また、カソードでの電気化学反応は、固体高分子電解質から来るプロトンと酸素分子（Ｏ2）が反応して酸素分子が水（Ｈ2Ｏ）に還元される電気化学反応であり、これらの電気化学反応における触媒活性の向上である。そして、このような固体高分子形燃料電池のアノードとカソードの電極触媒としては、通常、白金などの貴金属が用いられるが、これらの貴金属は高価であるので、固体高分子形燃料電池の実用化や普及を加速するために、電極単位面積当たりの使用量の低減が求められ、更に、その為には触媒活性の更なる向上が必須である。 A polymer electrolyte fuel cell is required to have a high output per unit electrode area. One of the most effective solutions is to improve the catalytic activity of the electrochemical reaction that occurs in the electrocatalyst constituting the anode and cathode. Here, the electrochemical reaction at the anode is a reaction using hydrogen as a fuel, and is an electrochemical reaction in which hydrogen molecules (H 2 ) are oxidized into hydrogen cations (H + , protons). Is an electrochemical reaction in which protons coming from a solid polymer electrolyte and oxygen molecules (O 2 ) react to reduce oxygen molecules to water (H 2 O), and the catalyst in these electrochemical reactions It is an improvement in activity. In general, noble metals such as platinum are used as the anode and cathode electrode catalyst of such a polymer electrolyte fuel cell. However, since these noble metals are expensive, the polymer electrolyte fuel cell is put to practical use. In order to accelerate the spread, the reduction of the amount used per electrode unit area is required, and further improvement of the catalyst activity is essential for this purpose.
固体高分子形燃料電池用触媒の使用量削減には、これまで、微粒子化による単位質量当りの反応に関与する表面積の拡大と、白金と他の金属との合金化による触媒単位表面積当りの反応電流密度の増大（高活性化）の二つの方法が検討されてきた。これまでの精力的な研究により、合金化に関しては、非特許文献１、非特許文献２にカソード反応、アノード反応に適した種々の合金の研究結果がまとめられている。しかしながら、実用展開のためには、白金へ添加する合金元素の溶出によるプロトン伝導度の低下（プロトンと溶出イオンとのイオン交換）、また、溶出元素の溶出による活性の低下など、解決すべき課題が残されている。 To reduce the amount of catalyst used for polymer electrolyte fuel cells, we have so far increased the surface area involved in the reaction per unit mass by atomization and the reaction per unit surface area of the catalyst by alloying platinum with other metals. Two methods of increasing current density (high activation) have been studied. Based on energetic research so far, with regard to alloying, Non-Patent Document 1 and Non-Patent Document 2 summarize the research results of various alloys suitable for cathode reaction and anode reaction. However, for practical development, problems to be solved such as a decrease in proton conductivity due to elution of alloy elements added to platinum (ion exchange between protons and elution ions) and a decrease in activity due to elution of elution elements. Is left.
他方、触媒を担持する担体と触媒金属との相互作用を改善することによる活性向上の試みも検討されている。非特許文献３は、湿式の白金担持プロセスにおける担体カーボンブラックの表面状態の効果を検討し、特に、カーボンブラック表面をアルカリ処理することで、担持する白金の微粒子化、高担持化を行っている。 On the other hand, attempts have been made to improve the activity by improving the interaction between the catalyst-supporting carrier and the catalyst metal. Non-Patent Document 3 examines the effect of the surface state of the carrier carbon black in the wet platinum loading process, and in particular, by carrying out an alkali treatment on the surface of the carbon black, the supported platinum particles are made finer and highly loaded. .
特許文献１には、触媒成分である金属微粒子を炭素担体へ担持する製造法の工夫による触媒性能の改善が示されている。従来の湿式の化学的還元法、或いは、金属塩の含浸乾固後の還元雰囲気中熱処理還元法では、担体表面上に均質に粒子径の揃った微粒子の担持ができないが、還元、或いは不活性ガスの高温炉中へカーボン担体と金属前駆体の懸濁液を噴霧することで、均質に粒子径の揃った微粒子を高密度にカーボン担体に担持させるというものである。また、特許文献１では、使用するカーボン担体の表面特性についても記載されている。酸化された炭素表面では、ヒドロキシル基、カルボキシル基、アルデヒド基等の官能基が形成され、それにより表面をより親水性にすることが可能であること、還元された炭素表面は、末端が水素となり、それにより疎水性が促進されること等が記載されている。 Patent Document 1 discloses an improvement in catalyst performance by devising a production method for supporting metal fine particles as a catalyst component on a carbon support. The conventional wet chemical reduction method or the heat treatment reduction method in a reducing atmosphere after impregnation to dryness with a metal salt cannot support fine particles with a uniform particle size on the support surface, but it is reduced or inactive. By spraying a suspension of a carbon support and a metal precursor into a gas high-temperature furnace, fine particles having a uniform particle diameter are supported on the carbon support at a high density. Moreover, in patent document 1, it describes also about the surface characteristic of the carbon support | carrier to be used. On the oxidized carbon surface, functional groups such as hydroxyl groups, carboxyl groups, and aldehyde groups are formed, which can make the surface more hydrophilic, and the reduced carbon surface is hydrogen-terminated. It is described that the hydrophobicity is promoted thereby.
特許文献２には、多孔質シリカを鋳型としてその細孔に炭素源を充填し炭素化させた後、シリカを除去することで、多孔質シリカの特徴である精密に制御された細孔構造をそのまま反映した担体炭素を得ることが開示されている。更に、予めシリカ細孔中に白金微粒子を担持させてから炭素質前駆体を充填することにより、白金微粒子を炭素表面に固定した細孔構造炭素触媒を得ることができ、また、このようにして得られた触媒は細孔構造を適当なサイズに制御することにより、プロトン伝導樹脂との白金微粒子との接触面積を高めることが可能となり高性能な固体高分子形燃料電池を得ることができるとされている。 Patent Document 2 describes a precisely controlled pore structure that is characteristic of porous silica by removing the silica after filling the pores with a carbon source and carbonizing the porous silica as a template. It is disclosed to obtain a carrier carbon that is reflected as it is. Furthermore, by loading platinum fine particles in the silica pores and then filling the carbonaceous precursor, it is possible to obtain a pore structure carbon catalyst in which the platinum fine particles are fixed on the carbon surface. By controlling the pore structure to an appropriate size, the obtained catalyst can increase the contact area between the proton conductive resin and the platinum fine particles, and a high-performance solid polymer fuel cell can be obtained. Has been.
一般に、カーボンブラックを担体とした白金触媒における白金の利用率が低くなる原因は、プロトン伝導性樹脂と白金との接触面積が十分でないことである。特許文献３、特許文献４、特許文献５では、プロトン伝導性樹脂と白金との接触面積を高めることを目的としている。具体的には、白金を担持した触媒担体について、その表面全体にプロトン解離性官能基（酸性官能基）を結合させる、あるいは、その表面全体を上記と同様の官能基を有する化合物で被覆するというもので、プロトン解離性官能基を介して白金へのプロトン伝導経路が確保され、白金の利用率が大幅に高まるというものである。 In general, the reason why the platinum utilization rate in a platinum catalyst using carbon black as a carrier is low is that the contact area between the proton conductive resin and platinum is not sufficient. In patent document 3, patent document 4, and patent document 5, it aims at raising the contact area of proton-conductive resin and platinum. Specifically, a platinum-supported catalyst support is bonded to a proton dissociable functional group (acidic functional group) over the entire surface, or the entire surface is coated with a compound having the same functional group as described above. Therefore, a proton conduction path to platinum is ensured through a proton dissociable functional group, and the utilization rate of platinum is greatly increased.
そして、特許文献３では、プロトン解離性官能基を有するシラン化合物を使用して、担体カーボン表面の含酸素官能基（フェノール性水酸基、カルボキシル基、ラクトン基、キノン基、無水カルボン酸基等）と反応させることで触媒表面をプロトン解離性官能基で被覆することが開示されている。 And in patent document 3, using the silane compound which has a proton dissociative functional group, oxygen-containing functional group (Phenolic hydroxyl group, carboxyl group, lactone group, quinone group, carboxylic anhydride group, etc.) on the surface of carrier carbon It is disclosed that the catalyst surface is coated with a proton-dissociable functional group by reacting.
特許文献４では、酸性官能基が化学的に結合した炭素担体が開示され、更に、炭素担体をプラズマ処理することで炭素担体表面に活性なラジカルを生成させてから酸性官能基を導入する（酸性官能基を有する化合物と反応させる）と、酸性官能基が炭素担体の表面に効率よく化学結合できることが記載されている。炭素担体のプラズマ処理の効果は、むしろ、炭素担体の表面に含酸素官能基が形成されて、酸性官能基を有する化合物との反応が効率よく起こることによるものと推測される。また、酸性官能基を有する化合物として、ビニルスルホン酸塩、メタクリレート系リン酸塩などを用いて、炭素担体を表面修飾している。 Patent Document 4 discloses a carbon support in which an acidic functional group is chemically bonded. Further, an active functional group is introduced after generating an active radical on the surface of the carbon support by plasma treatment of the carbon support (acidic). It is described that an acidic functional group can be efficiently chemically bonded to the surface of a carbon support when it is reacted with a compound having a functional group. Rather, the effect of the plasma treatment of the carbon support is presumably due to the fact that an oxygen-containing functional group is formed on the surface of the carbon support and the reaction with the compound having an acidic functional group occurs efficiently. Further, the surface of the carbon support is modified using vinyl sulfonate, methacrylate phosphate, or the like as the compound having an acidic functional group.
特許文献５では、スルホンサン酸基、カルボン酸基、リン酸基等の水素イオン伝導性を付与できる作用基（プロトン解離性官能基、酸性官能基）を有するイオノマーを炭素担体表面に施して、担体表面に水素イオン伝導性を付与することが開示されている。前記イオノマーは、担体表面の官能基を基点としてモノマーを重合させるいわゆるグラフト化処理することにより形成される。具体的には、スチレン系、アクリル系、メタクリル系、アリルスルホン系、フェニル系のモノマーを重合させた後に、末端をスルホン化してプロトン解離性官能基を付与するというものである。 In Patent Document 5, an ionomer having a functional group (proton dissociable functional group, acidic functional group) capable of imparting hydrogen ion conductivity such as a sulfonic acid group, a carboxylic acid group, and a phosphoric acid group is applied to the surface of a carbon carrier, It is disclosed that hydrogen ion conductivity is imparted to the support surface. The ionomer is formed by a so-called grafting treatment in which a monomer is polymerized using a functional group on the surface of a carrier as a base point. Specifically, after polymerizing a styrene, acrylic, methacrylic, allylsulfone, or phenyl monomer, the terminal is sulfonated to give a proton dissociable functional group.
前述の担体処理は、酸性官能基を付与するものであるが、反対に、塩基性官能基を炭素担体の表面に付与することも行われている。 The above-described carrier treatment imparts an acidic functional group, but conversely, a basic functional group is imparted to the surface of the carbon carrier.
特許文献６では、カーボン担体の表面芳香族環にアミノ基等の塩基性官能基を結合させることによって、カーボン担体粒子同士を凝集させることなく、カーボン担体粒子を固体高分子電解質樹脂で被覆できることが開示されている。固体高分子電解質樹脂は酸性であり（陰性のイオン交換基を有する）、カーボン担体の表面を塩基性（正電荷に帯電）としているので、固体高分子電解質樹脂とカーボン担体は互いに静電力で引き合うことになる。前記結果として形成される組織は、触媒近傍に三相界面を形成して反応サイトを十分に増大することができるとしている。 In Patent Document 6, carbon carrier particles can be coated with a solid polymer electrolyte resin without agglomerating the carbon carrier particles by bonding a basic functional group such as an amino group to the surface aromatic ring of the carbon carrier. It is disclosed. Since the solid polymer electrolyte resin is acidic (has a negative ion exchange group) and the surface of the carbon support is basic (positively charged), the solid polymer electrolyte resin and the carbon support attract each other by electrostatic force. It will be. The structure formed as a result can form a three-phase interface in the vicinity of the catalyst to sufficiently increase the reaction site.
特許文献７では、カーボン担体の表面をN,N-ジメチルアミノプロピルアミン等の塩基性表面処理剤で処理することによって、プロトン伝導性ポリマーがカーボン担体表面から剥離するのを抑制できることが開示されている。これは、塩基性表面処理剤で処理することでカーボン担体の表面が塩基性に改質され、前記塩基性表面がプロトン伝導性ポリマーの酸性基とイオン結合するので、プロトン伝導性ポリマーの剥離が抑制できるとされている。 Patent Document 7 discloses that treatment of the surface of a carbon support with a basic surface treatment agent such as N, N-dimethylaminopropylamine can suppress the separation of the proton conductive polymer from the surface of the carbon support. Yes. This is because the surface of the carbon carrier is modified to be basic by treatment with a basic surface treatment agent, and the basic surface is ionically bonded to the acidic group of the proton conductive polymer, so that the proton conductive polymer is peeled off. It can be suppressed.
特許文献３には、担体カーボン表面にシラン化合物を介して酸性官能基を結合させ、これによって水素イオンチャンネル（プロトン伝導経路）を形成することが開示されている一方、これとは反対に、アミド基やアミン基などの塩基性官能基（非共有電子対を有する窒素原子を持つ）を持つシラン化合物を利用して担体カーボン表面に結合させることも開示されている。塩基性の表面にした担体カーボンの場合には、スルホン酸基などを有して酸性である高分子電解質を強く引き付け、この引き付けられた高分子電解質によって担体カーボンの表面近傍に水素イオンチャンネルを形成するというものである。
特許文献１では、加熱温度、懸濁液の分散状態などにより金属微粒子のサイズや担持率を制御することになるが、一般的に、液相での化学的還元反応に比較して、気相で反応速度を制御して均質な微粒子を生成させ、且つ、同時に生成した微粒子を高密度に担体へ担持させるのは困難であり、担体の性状依存性が大きいという問題が残る。また、活性改善の本質が白金の均質・微粒子担持では、その改善効果が小さいという課題も残る。さらに、担体相を構成する炭素粒子の表面特性について、上述のように記載されているが、高い触媒活性や耐久性等の特性向上に関する担体の表面性状について具体的な示唆がない。 In Patent Document 1, the size and supporting rate of the metal fine particles are controlled by the heating temperature, the dispersion state of the suspension, etc., but generally in the gas phase as compared with the chemical reduction reaction in the liquid phase. Thus, it is difficult to control the reaction rate to produce homogeneous fine particles and to simultaneously support the fine particles produced at a high density on the carrier, and there remains a problem that the property dependence of the carrier is large. Further, when the essence of activity improvement is homogeneous and fine particle support of platinum, the problem that the improvement effect is small remains. Furthermore, although the surface characteristics of the carbon particles constituting the support phase are described as described above, there is no specific suggestion about the surface properties of the support regarding improvement in characteristics such as high catalytic activity and durability.
特許文献２では、三次元的に発達した細孔構造が担体構造の特徴であるが、細孔内部に担持された白金微粒子は細孔サイズを制御してもプロトン伝導樹脂と接触させることが困難であり、白金の利用率を高めるのが難しい。鋳型炭素の製造コストと触媒パフォーマンスとの総合的視点から、いわゆる導電性カーボンブラックを担体とした触媒と比較して、本質的な優位性に乏しいという点で課題が残る。すなわち、担体構造については前述のように記載されているが、担体の表面性状までは言及しておらず、実用的には前記課題が残る。 In Patent Document 2, a three-dimensionally developed pore structure is a feature of the carrier structure, but platinum fine particles supported inside the pore are difficult to contact with the proton conductive resin even if the pore size is controlled. It is difficult to increase the utilization rate of platinum. From the comprehensive point of view of the production cost of the template carbon and the catalyst performance, there remains a problem in that the essential advantage is poor compared to a catalyst using so-called conductive carbon black as a carrier. That is, the carrier structure is described as described above, but the surface properties of the carrier are not mentioned, and the above problem remains practically.
特許文献３、４、５では、炭素担体の表面にプロトン解離性官能基（水素イオン解離性官能基、酸性官能基）で被覆して炭素担体表面にプロトン伝導性を付与することが開示されているが、酸性官能基を施すために行う炭素表面の官能基を利用したグラフト処理はグラフトする分子の分子量によらず一般に炭素担体粒子同士の相互作用を大きく変化させ、その結果として炭素担体粒子の分散状態が大きく変わるため、炭素担体粒子が本来有する凝集構造が崩れるという副次的作用を避けることが難しい。そして、炭素担体の凝集構造が崩れると、電子伝導のネットワークが弱まり触媒層の電気抵抗が増大し、また、細孔構造が崩れるためにガス透過性が低下し電極の重負荷特性が低下するなどの新たな課題を発生させてしまう。すなわち、前記特許文献では、炭素担体にプロトン伝導性を付与する担体表面性状の改質方法について記載されているが、それに伴う電子伝導性及びガス透過性の低下や、電子伝導性及びガス透過性とのバランスを考慮した前記担体表面性状については記載や示唆がなされていない。 Patent Documents 3, 4, and 5 disclose that the surface of a carbon support is covered with a proton dissociable functional group (hydrogen ion dissociable functional group, acidic functional group) to impart proton conductivity to the surface of the carbon support. However, the grafting treatment using the functional group on the carbon surface for applying the acidic functional group generally changes greatly the interaction between the carbon support particles irrespective of the molecular weight of the molecule to be grafted. Since the dispersion state changes greatly, it is difficult to avoid the secondary effect that the aggregated structure inherent to the carbon support particles is destroyed. And if the aggregate structure of the carbon support collapses, the electron conduction network weakens and the electrical resistance of the catalyst layer increases, and the pore structure collapses, so the gas permeability decreases and the heavy load characteristics of the electrode decrease. Will cause new challenges. That is, the above-mentioned patent document describes a method for modifying the surface property of a carrier that imparts proton conductivity to a carbon carrier. However, the accompanying decrease in electron conductivity and gas permeability, and electron conductivity and gas permeability are described. There is no description or suggestion about the surface properties of the carrier considering the balance.
特許文献３、６、７では、炭素担体の表面を塩基性官能基で被覆して、プロトン伝導性固体高分子電解質を担体表面に密着させ、電解質の剥離を防いだり、担体の表面近傍に水素イオンチャンネルを形成することが開示されているが、担体の表面全体に亘って固体高分子電解質との親和性を高めると、担体粒子全体が固体高分子電解質で覆われてしまうことになり、担体粒子同士の相互作用を弱め、担体粒子の連結が途切れて電子伝導性が低下するという問題がある。また、上述と同様に、炭素担体の凝集構造が崩れて、ガス透過性が低下するという問題も生じる。前記特許文献では、炭素担体の表面を塩基性官能基で被覆してプロトン伝導性固体電解質との相互作用を強めることは記載されているが、それに伴う電子伝導性及びガス透過性の低下や、電子伝導性及びガス透過性とのバランスを考慮した前記担体表面性状については記載や示唆がなされていない。 In Patent Documents 3, 6, and 7, the surface of the carbon support is coated with a basic functional group, and the proton conductive solid polymer electrolyte is adhered to the support surface to prevent the separation of the electrolyte. Although it is disclosed that an ion channel is formed, if the affinity with the solid polymer electrolyte is increased over the entire surface of the carrier, the entire carrier particle is covered with the solid polymer electrolyte, There is a problem that the interaction between the particles is weakened, the connection of the carrier particles is broken, and the electron conductivity is lowered. Further, similarly to the above, there is a problem that the aggregate structure of the carbon support is broken and the gas permeability is lowered. In the above-mentioned patent document, it is described that the surface of the carbon support is covered with a basic functional group to enhance the interaction with the proton conductive solid electrolyte, but the accompanying decrease in electron conductivity and gas permeability, There is no description or suggestion about the surface properties of the carrier considering the balance between electron conductivity and gas permeability.
このように従来の技術では、白金の利用率を高めることを狙い、粒子分散状態の改善、担体の三次元的構造の改善、担体表面を酸性官能基で被覆すること、或いは担体表面を塩基性官能基で被覆することがそれぞれ行われているが、本質的に担体を含めた白金触媒の活性改善には至っていなかった。 As described above, the conventional technology aims to increase the utilization rate of platinum, improve the particle dispersion state, improve the three-dimensional structure of the carrier, coat the carrier surface with acidic functional groups, or make the carrier surface basic. Although each coating with a functional group has been performed, the activity of the platinum catalyst including the support has not been improved.
本発明は、上記問題を解決するためになされたものであって、白金など金属微粒子を炭素材料に担持してなる触媒において、炭素材料と金属微粒子との相互作用を強めるという新たな視点により触媒の活性を本質的に高めることを狙ったものであり、固体高分子形燃料電池電極用の高活性触媒を提供することを目的とする。 The present invention has been made to solve the above-described problem, and is a catalyst in which metal fine particles such as platinum are supported on a carbon material, and the catalyst is developed from a new viewpoint of strengthening the interaction between the carbon material and the metal fine particles. The purpose of the present invention is to essentially increase the activity of the catalyst, and an object thereof is to provide a highly active catalyst for a polymer electrolyte fuel cell electrode.
本発明者らは、上記課題を解決するために、白金などの触媒能を有する金属微粒子を担持してなる触媒において、担体である炭素材料の表面構造を鋭意検討した。その結果、特定の表面構造を有する炭素材料に金属微粒子を担持させることにより、触媒活性が大幅に改善することを見出し、本発明に至った。具体的には、特定の比表面積の炭素材料で、プロトン吸着性（塩基性）とプロトン解離性（酸度）の両方を考慮して、塩基性官能基量によるプロトン吸着性の制御と同時に、酸度によるプロトン解離性を制御し、金属微粒子を担持させることで触媒活性を高められることを見出したものである。更に、前記炭素材料について、特定の細孔サイズを制御したミクロ孔を有する構造にすることで、より触媒活性を高められることも見出した。 In order to solve the above-mentioned problems, the present inventors diligently studied the surface structure of a carbon material as a support in a catalyst formed by supporting fine metal particles having catalytic ability such as platinum. As a result, the present inventors have found that catalytic activity is greatly improved by supporting metal fine particles on a carbon material having a specific surface structure, and the present invention has been achieved. Specifically, a carbon material with a specific surface area takes into account both proton adsorptivity (basic) and proton dissociation (acidity), and at the same time controls proton adsorptivity by the amount of basic functional groups. It has been found that the catalytic activity can be enhanced by controlling the proton dissociation property of the catalyst and supporting metal fine particles. Furthermore, it has also been found that the catalytic activity of the carbon material can be further enhanced by adopting a structure having micropores in which a specific pore size is controlled.
すなわち、本発明は、以下を要旨とするものである。
（１）炭素材料に金属微粒子を担持してなる触媒であって、炭素材料が以下の（ａ）〜（ｄ）を同時に満たすことを特徴とする固体高分子形燃料電池電極用触媒。
（ａ）窒素吸着比表面積（SBET；m2/g）：２００≦ＳBET≦８２２
（ｂ）塩基性官能基量（B；meq/g）とＳBETの比：０．５≦Ｂ／ＳBET≦２．６８
（ｃ）全酸度（TA；meq/g）とＳBETの比：０．０５≦TA／ＳBET≦２
（ｄ）塩基性官能基量Ｂと全酸度TAの比：２≦Ｂ／TA≦１５
That is, the gist of the present invention is as follows.
(1) A catalyst for solid polymer fuel cell electrodes, which is a catalyst obtained by supporting metal fine particles on a carbon material, and the carbon material simultaneously satisfies the following (a) to (d).
(A) Nitrogen adsorption specific surface area (S BET ; m 2 / g): 200 ≦ S BET ≦ 822
(B) Ratio of basic functional group amount (B; meq / g) to S BET : 0.5 ≦ B / S BET ≦ 2.68
(C) Ratio of total acidity (TA; meq / g) to S BET : 0.05 ≦ TA / S BET ≦ 2
(D) Ratio of basic functional group amount B to total acidity TA: 2 ≦ B / TA ≦ 15
（２）前述の炭素材料が表面にミクロ孔を有し、且つ、ミクロ孔の細孔容積（Vmicro；ml/g）が０．１≦Ｖmicro≦０．８であることを特徴とする（１）の固体高分子形燃料電池電極用触媒。 (2) The above-mentioned carbon material has micropores on the surface, and the pore volume (V micro ; ml / g) of the micropores is 0.1 ≦ V micro ≦ 0.8. (1) The catalyst for a polymer electrolyte fuel cell electrode.
（３）前述の炭素材料が表面にミクロ孔を有し、且つ、ミクロ孔の平均直径（Dmicro；nm）が１．０≦Ｄmicro≦３．０であることを特徴とする（１）又は（２）に記載の固体高分子形燃料電池用触媒。 (3) The above-mentioned carbon material has micropores on the surface, and the average diameter (D micro ; nm) of the micropores is 1.0 ≦ D micro ≦ 3.0 (1) Or the catalyst for polymer electrolyte fuel cells as described in (2).
（４）上述の（１）〜（３）に記載の固体高分子形燃料電池用触媒を含有する電極を、正極または負極の少なくとも一方に用いられていることを特徴とする固体高分子形燃料電池。 (4) A polymer electrolyte fuel characterized in that an electrode containing the catalyst for a polymer electrolyte fuel cell as described in (1) to (3) above is used for at least one of a positive electrode and a negative electrode. battery.
本発明の固体高分子形燃料電池用電極触媒によれば、担体の比表面積や細孔構造、担体表面の塩基性と酸度の両方を制御しているので、その表面に担持した金属微粒子の触媒活性が極めて高くなり、従来よりも高い活性の触媒を提供することができる。また、かかる高活性の触媒を電極に適用することにより、触媒金属の使用量を削減し、且つ高性能な燃料電池を提供することが可能となる。 According to the electrode catalyst for a polymer electrolyte fuel cell of the present invention, both the specific surface area and pore structure of the carrier, and the basicity and acidity of the carrier surface are controlled. The activity becomes extremely high, and a catalyst having higher activity than before can be provided. In addition, by applying such a highly active catalyst to the electrode, it is possible to reduce the amount of catalyst metal used and provide a high-performance fuel cell.
本発明の燃料電池用触媒は、炭素材料の表面に金属微粒子を担持してなる触媒の活性を改善するもので、具体的には、炭素材料表面と金属表面の相互作用を制御することにより金属微粒子の電子状態を変化させ、これによって金属表面で生じる電気化学的な反応の過電圧を低減させ、或いは、反応速度を高めることを意図するものである。 The fuel cell catalyst of the present invention improves the activity of a catalyst formed by supporting metal fine particles on the surface of a carbon material. Specifically, the catalyst is controlled by controlling the interaction between the carbon material surface and the metal surface. It is intended to change the electronic state of the fine particles, thereby reducing the overvoltage of the electrochemical reaction occurring on the metal surface or increasing the reaction rate.
一般的に、炭素材料は、炭素のｓｐ2結合よりなる縮合多環芳香族の積層した構造部位（黒鉛構造部位、グラファイト構造部位）と、ｓｐ3結合からなるダイヤモンド型結晶構造部位と、ｓｐ2結合とｓｐ3結合が混合して更にダングリングボンドを含む非晶質炭素部位とが混合した構造を持つ。特に固体高分子電解質形燃料電池の触媒では、炭素材料の担体に白金を主成分とした貴金属微粒子を担持させた触媒を用いる。したがって、担体である炭素材料には、電子伝導性、高電位での耐酸化安定性（特に、カソードにおいて）が要求され、前記両特性を満たす黒鉛構造が適する。しかしながら、金属微粒子を担体表面に強く吸着担持させるためには、黒鉛構造におけるπ電子面で表面が構成される縮合多環芳香族のグラフェンシート（炭素六員環シート）の面上は不適当であり、末端が酸素や水素などと結合したグラフェンシートのエッジで構成される面が、電荷移動と極性の観点から金属微粒子の吸着に適することが推察される。この際の担体表面と金属微粒子との相互作用を高めるための炭素表面の構造を鋭意検討した結果、担体表面のプロトン吸引性とプロトン解離性の両方を有することで、金属微粒子の担持した炭素材料触媒の活性を高めることに成功した。すなわち、担体表面に塩基性官能基と酸性官能基の両方を共存させることである。更に、この炭素材料のプロトン吸引性とプロトン解離性の指標として、各々、塩化水素の吸着量、水酸化ナトリウムの吸着量が最適であることを見出した。これらの指標の最適な範囲は以下の通りである。即ち、塩化水素の吸着量で表される塩基性官能基量Ｂ（meq/g）の表面積当りの平均値Ｂ/ＳBET（meq/m2）は、０．５≦Ｂ/ＳBET≦８であることが好ましい。Ｂ/ＳBETが０．５未満ではプロトン吸引性が弱く触媒活性の改善の程度が小さくなってしまう。また、Ｂ/ＳBETが８を超えると実質的に炭素材料の黒鉛構造性が低下し、その結果、電子伝導性、耐酸化安定性が低下して、固体高分子形燃料電池電極用の触媒として不適当となってしまう。ここで、表面積を表す指標としては、窒素ガスの吸着により評価されるＢＥＴ解析で評価した表面積ＳBET（m2/g）が適切である。プロトン吸引性は、金属表面から供与される電子を受容する炭素表面の電子受容性の間接的な指標と推察される。金属表面から担体への電子移動が多ければそれだけ金属微粒子と担体との相互作用が強まり、同時に金属微粒子の電子状態の変化が触媒活性の改善に繋がっているものと推察される。 In general, a carbon material is composed of a condensed polycyclic aromatic structure part (graphite structure part, graphite structure part) composed of carbon sp 2 bonds, a diamond-type crystal structure part composed of sp 3 bonds, and sp 2. It has a structure in which bonds and sp 3 bonds are mixed and amorphous carbon sites including dangling bonds are mixed. In particular, as a catalyst for a solid polymer electrolyte fuel cell, a catalyst in which noble metal fine particles mainly composed of platinum are supported on a carbon material carrier is used. Therefore, the carbon material as a carrier is required to have electronic conductivity and oxidation resistance stability at a high potential (particularly in the cathode), and a graphite structure that satisfies both of the above characteristics is suitable. However, in order to strongly adsorb and support the metal fine particles on the surface of the carrier, the surface of the condensed polycyclic aromatic graphene sheet (carbon six-membered ring sheet) whose surface is composed of the π-electron surface in the graphite structure is inappropriate. It is presumed that the surface composed of the edge of the graphene sheet bonded to oxygen, hydrogen, or the like at the end is suitable for adsorption of metal fine particles from the viewpoint of charge transfer and polarity. As a result of earnestly examining the structure of the carbon surface for enhancing the interaction between the carrier surface and the metal fine particles at this time, the carbon material carrying the metal fine particles has both the proton attracting property and the proton dissociating property of the carrier surface. We succeeded in increasing the activity of the catalyst. That is, both basic functional groups and acidic functional groups are allowed to coexist on the carrier surface. Furthermore, the present inventors have found that the adsorption amount of hydrogen chloride and the adsorption amount of sodium hydroxide are optimum as indicators of proton attractiveness and proton dissociation of the carbon material, respectively. The optimal range of these indicators is as follows. That is, the average value B / S BET (meq / m 2 ) per surface area of the basic functional group amount B (meq / g) expressed by the amount of hydrogen chloride adsorbed is 0.5 ≦ B / S BET ≦ 8. It is preferable that If B / S BET is less than 0.5, the proton-attracting property is weak and the degree of improvement in catalyst activity is small. Further, when B / S BET exceeds 8, the graphite structure of the carbon material is substantially lowered, and as a result, the electron conductivity and the oxidation resistance stability are lowered, and the catalyst for the polymer electrolyte fuel cell electrode As inappropriate. Here, as the index representing the surface area, the surface area S BET (m 2 / g) evaluated by BET analysis evaluated by adsorption of nitrogen gas is appropriate. The proton attractive property is presumed to be an indirect indicator of the electron acceptability of the carbon surface that accepts electrons donated from the metal surface. It is presumed that the more the electrons move from the metal surface to the carrier, the stronger the interaction between the metal fine particles and the carrier, and at the same time, the change in the electronic state of the metal fine particles leads to the improvement of the catalytic activity.
他方、ＮａＯＨの吸着量で表される酸性官能基量TA（meq/g）の表面積当りの平均値TA/ＳBET（meq/m2）は、０．０５≦TA/ＳBET≦２であることが好ましい。前記範囲で酸性官能基が担体表面に存在すると、前記プロトン吸引性の効果を阻害することなく担体表面にプロトン伝導性を付与でき、プロトン伝導性固体電解質とのプロトン授受も促進できる。その結果として総合的に触媒活性が向上する。TA/ＳBETが０．０５未満では一般的な炭素材料表面と大きく性状が異なり担体として不適当である。また、TA/ＳBETが２を超えると実質的にプロトン吸引性の特徴を打ち消す効果が高くなり、プロトン吸引性による活性向上効果が消失するため本発明には適当でない。 On the other hand, the average value TA / S BET (meq / m 2 ) per surface area of the acidic functional group amount TA (meq / g) expressed by the adsorption amount of NaOH is 0.05 ≦ TA / S BET ≦ 2. It is preferable. When the acidic functional group is present on the surface of the carrier within the above range, proton conductivity can be imparted to the surface of the carrier without inhibiting the proton attracting effect, and proton exchange with the proton conductive solid electrolyte can be promoted. As a result, overall catalytic activity is improved. When TA / S BET is less than 0.05, the properties are greatly different from those of general carbon material surfaces, which are not suitable as carriers. Further, when TA / S BET exceeds 2, the effect of substantially canceling the proton attracting characteristics becomes high, and the activity improving effect by proton attracting characteristics disappears, so that it is not suitable for the present invention.
これら塩基性官能基量Ｂと酸性官能基量TAの各々の絶対量を前述のように規定すると同時に、その存在比を規定することが担体表面性状による触媒活性改善には必須である。本発明者が鋭意検討の結果、TAとＢの相対的な存在比の最適な範囲は、２≦Ｂ/TA≦１５である。Ｂ/TAが２よりも小さいと、相対的に酸性官能基の寄与が大きく塩基性官能基による触媒金属の活性改善効果が現れず、他方、Ｂ/TAが１５よりも大きいと酸性官能基によるプロトン伝導補助効果が現れず活性の改善が小さくなってしまうものと推察される。 The absolute amount of each of these basic functional group amounts B and acidic functional group amounts TA is defined as described above, and at the same time, it is essential to improve the catalyst activity due to the surface properties of the support. As a result of intensive studies by the inventor, the optimum range of the relative abundance ratio of TA and B is 2 ≦ B / TA ≦ 15. If B / TA is less than 2, the contribution of the acidic functional group is relatively large, and the effect of improving the catalytic metal activity by the basic functional group does not appear. On the other hand, if B / TA is greater than 15, the acidic functional group It is presumed that the proton conduction assisting effect does not appear and the improvement in activity becomes small.
更に、金属微粒子と炭素材料との吸着を強めるためには、金属微粒子と担体との接触面積を大きくすることが重要であり、そのための指標は、窒素吸着比表面積（SBET；m2/g）である。高密度に金属微粒子を担持させるためには、炭素材料表面の表面積が一定値以上であることが必要である。また、炭素材料の電子伝導性維持の観点から、表面積の上限も同時に存在する。鋭意検討の結果、本発明の上記表面性状を有する炭素材料では、その効果を発現するためには、炭素材料の比表面積が２００≦ＳBET≦２０００であることが判明した。更に好ましくは、５００≦ＳBET≦２０００である。ＳBETが２００未満では炭素材料表面に数nmサイズの金属微粒子を高密度に担持させることが困難となり、燃料電池の実用上の性能を発揮することが出来ず、本発明には不適当である。ＳBETが２０００を超えると炭素材料の電子伝導性が低下して電極触媒としては不適当である。 Furthermore, in order to enhance the adsorption between the metal fine particles and the carbon material, it is important to increase the contact area between the metal fine particles and the carrier, and the index for this is the nitrogen adsorption specific surface area (S BET ; m 2 / g ). In order to carry metal fine particles at a high density, the surface area of the carbon material surface needs to be a certain value or more. Further, from the viewpoint of maintaining the electronic conductivity of the carbon material, there is also an upper limit of the surface area. As a result of intensive studies, it was found that the carbon material having the above surface properties of the present invention has a specific surface area of 200 ≦ S BET ≦ 2000 in order to exhibit the effect. More preferably, 500 ≦ S BET ≦ 2000. If S BET is less than 200, it becomes difficult to carry high-density metal fine particles of several nanometers on the surface of the carbon material, and the practical performance of the fuel cell cannot be exhibited, which is inappropriate for the present invention. . When S BET exceeds 2000, the electronic conductivity of the carbon material is lowered and it is unsuitable as an electrode catalyst.
前記比表面積に加え、炭素材料に金属微粒子が吸着するのに適した大きさの細孔を存在させることは、金属微粒子と炭素材料表面との接触面積を大きくするのに更に有効である。 In addition to the specific surface area, the presence of pores having a size suitable for adsorbing metal fine particles on the carbon material is more effective for increasing the contact area between the metal fine particles and the carbon material surface.
鋭意検討の結果、金属微粒子のサイズは実用上１〜５nm直径であるが、この大きさの微粒子に適する細孔のサイズはいわゆるミクロ孔（2nm以下の細孔）に属することが推察される。本発明において、炭素材料のミクロ孔の大きさ（直径）を検討した結果、ミクロ孔の平均直径（Dmicro；nm）は１．０≦Ｄmicro≦３．０であることがより好ましいことを見出した。Ｄmicroが１．０未満では、金属微粒子との接触面積が小さ過ぎて金属微粒子と炭素材料との間の電子移動量が少なく、活性改善効果が現れなくなってしまう場合がある。他方、Ｄmicroが３．０を超えると、金属微粒子が孔の中に埋没してしまって、実質的に触媒反応に関与できる金属微粒子の表面積が低下してしまい、やはり活性の改善効果が現れなくなってしまう場合がある。 As a result of intensive studies, the size of the metal fine particles is practically 1 to 5 nm in diameter, but it is presumed that the pore size suitable for the fine particles of this size belongs to so-called micropores (pores of 2 nm or less). In the present invention, as a result of examining the size (diameter) of the micropores of the carbon material, it is more preferable that the average diameter (D micro ; nm) of the micropores is 1.0 ≦ D micro ≦ 3.0. I found it. If D micro is less than 1.0, the contact area with the metal fine particles is too small, the amount of electron transfer between the metal fine particles and the carbon material is small, and the activity improving effect may not appear. On the other hand, when D micro exceeds 3.0, the metal fine particles are buried in the pores, and the surface area of the metal fine particles that can substantially participate in the catalytic reaction is reduced, and the effect of improving the activity appears again. It may disappear.
更に、ミクロ孔の容積も鋭意検討の結果、ミクロ孔の細孔容積（Vmicro；ml/g）は０．１≦Ｖmicro≦０．８であることが、本発明により好ましいことを見出した。Ｖmicroが０．１未満ではミクロ孔の数が少なく金属微粒子を高密度に担持させることが出来ず、本発明には不適当である場合がある。他方、Ｖmicroが０．８を超えると、炭素材料表面に占めるグラフェンシートのエッジの比率が高くなり過ぎ、耐酸化安定性が低下して燃料電池電極用触媒の担体としては適さなくなってしまう場合がある。 Furthermore, as a result of intensive studies on the micropore volume, it was found that the micropore pore volume (V micro ; ml / g) is preferably 0.1 ≦ V micro ≦ 0.8. . If V micro is less than 0.1, the number of micropores is small and metal fine particles cannot be supported at a high density, which may be inappropriate for the present invention. On the other hand, if V micro exceeds 0.8, the ratio of the graphene sheet edge to the surface of the carbon material becomes too high, and the oxidation resistance is lowered, making it unsuitable as a carrier for a catalyst for a fuel cell electrode. There is.
（炭素材料）
本発明に適する炭素材料は、塩基性官能基と酸性官能基による表面性状、比表面積、及びミクロ孔構造が本質的に重要であり、その他の構造に関して特に制限を加えるものではない。本発明に用いる炭素材料を具体的に例示するならば、ファーネス法で製造したカーボンブラック（ファーネスブラック）、アセチレンブラック、ランプブラックなどの各種カーボンブラック、種々の合成法で製造される繊維状の炭素材料、具体的には、単層のシングルウォールカーボンナノチューブ、多層のマルチウォールカーボンナノチューブ、直径がサブミクロンから数十ミクロンに至るカーボンナノファイバー、結晶性の高い人造黒鉛などの黒鉛粉、キッシュグラファイト、コークス粉、合成樹脂などの炭化水素系高分子化合物を熱処理して製造される各種炭素材料などを例示することができる。
(Carbon material)
In the carbon material suitable for the present invention, the surface properties, the specific surface area, and the micropore structure due to the basic functional group and the acidic functional group are essentially important, and there are no particular restrictions on other structures. Specific examples of the carbon material used in the present invention include carbon black (furnace black) produced by the furnace method, various carbon blacks such as acetylene black and lamp black, and fibrous carbon produced by various synthetic methods. Materials, specifically, single-walled single-walled carbon nanotubes, multi-walled multi-walled carbon nanotubes, carbon nanofibers with diameters ranging from submicron to several tens of microns, graphite powder such as highly crystalline artificial graphite, quiche graphite, Examples thereof include various carbon materials produced by heat-treating hydrocarbon polymer compounds such as coke powder and synthetic resin.
（炭素材料表面の制御方法）
本発明では、炭素材料表面の塩基性を高め、酸性を適度に制御することが本質的に重要であり、その製造方法に関しては何ら制限されるものではない。以下、本発明に適用される表面性状の改質方法を例示する。
(Control method of carbon material surface)
In the present invention, it is essentially important to increase the basicity of the carbon material surface and appropriately control the acidity, and the production method is not limited at all. Hereinafter, the surface property modification method applied to the present invention will be exemplified.
酸性官能基の導入には、いわゆる炭素材料の酸化手法を適用することが可能である。例示するならば、湿式の酸化として、硝酸などの強酸、過酸化水素による酸化などを例示することができ、また、気相反応として、オゾン酸化、空気、酸素雰囲気中での熱酸化などを例示することができる。また、ランプブラックや着色用途向けのいわゆるカラーカーボンと呼ばれるカーボンブラックでは、そもそもその製造工程において表面に多量の含酸素官能基が導入されており、これらのカーボンは特に酸素官能基を導入処理せずにそのまま本発明に適用可能である。 For introducing the acidic functional group, a so-called oxidation method of a carbon material can be applied. For example, wet oxidation can be exemplified by strong acid such as nitric acid, oxidation by hydrogen peroxide, etc., and gas phase reaction can be exemplified by ozone oxidation, thermal oxidation in air or oxygen atmosphere, etc. can do. In addition, in carbon black called so-called color carbon for lamp black and coloring applications, a large amount of oxygen-containing functional groups are introduced into the surface in the first place, and these carbons are not particularly introduced with oxygen functional groups. The present invention can be applied to the present invention as it is.
次いで、炭素材料表面に塩基性官能基を導入する方法を例示する。含酸素官能基で塩基性を発現するのは、縮合多環芳香族内でキノン基と環状エーテル酸素とが共存する場合である。このような構造を積極的に炭素材料表面に導入するには、先ず炭素材料表面に含酸素官能基を多量に導入した後、不活性雰囲気若しくは還元性雰囲気で、６００℃以上１２００℃以下の温度で熱処理する方法を適用することができる。この熱処理により一部の酸性官能基が脱離し、その一部は環状エーテルに結合状態が変化して炭素材料表面に残り、このエーテル酸素と共鳴するキノン基だけが選択的に表面に残存するため、炭素材料表面に塩基性構造が形成される。 Next, a method for introducing a basic functional group onto the surface of the carbon material will be exemplified. The oxygen-containing functional group exhibits basicity when the quinone group and the cyclic ether oxygen coexist in the condensed polycyclic aromatic. In order to actively introduce such a structure to the surface of the carbon material, first, a large amount of oxygen-containing functional groups are introduced to the surface of the carbon material, and then a temperature of 600 ° C. or more and 1200 ° C. or less in an inert atmosphere or a reducing atmosphere. A heat treatment method can be applied. Due to this heat treatment, some acidic functional groups are eliminated, and some of them are bonded to the cyclic ether and remain on the surface of the carbon material, and only the quinone group that resonates with this ether oxygen remains selectively on the surface. A basic structure is formed on the surface of the carbon material.
その他、含窒素官能基としては、弱い塩基性官能基としてアミノ基、比較的強い塩基性官能基としてピリジン型窒素を例示することが出来る。アミノ基の炭素材料表面への導入には、硝酸、過酸化水素などの酸化処理などの方法で含酸素官能基を炭素材料表面に多数導入しておいて、その酸素を窒素に置換する方法を適用することが可能である。たとえば、アンモニア水に炭素材料を分散させ、高圧・高温下で処理する、アンモニアガス中で炭素材料を加熱処理するなどの方法によって、炭素材料表面のカルボキシル基や水酸基はアミノ基に置換され、また縮合多環芳香族中のエーテル型酸素は窒素に置換される。 Other examples of the nitrogen-containing functional group include an amino group as a weak basic functional group and a pyridine type nitrogen as a relatively strong basic functional group. The introduction of amino groups onto the carbon material surface involves introducing a large number of oxygen-containing functional groups onto the carbon material surface by a method such as oxidation treatment with nitric acid or hydrogen peroxide, and replacing the oxygen with nitrogen. It is possible to apply. For example, by dispersing carbon material in ammonia water and treating it under high pressure and high temperature, or by heating the carbon material in ammonia gas, the carboxyl group or hydroxyl group on the surface of the carbon material is replaced with an amino group. The ether type oxygen in the condensed polycyclic aromatic is substituted with nitrogen.
その他、塩基性の化合物を炭素材料表面に吸着・固定化させることも好適に本発明に適用可能である。ピリジン型窒素を含有する複素員環、或いは、アミノ基を含む化合物を炭素材料に含浸・乾固させる、或いは、含浸・乾固した後、更に不活性雰囲気下で、１００〜１０００℃の温度で熱処理することによる固定化も好適に本発明に適用可能である。 In addition, it is also applicable to the present invention to adsorb and fix a basic compound on the surface of the carbon material. After impregnating / drying a carbon material with a hetero ring containing pyridine nitrogen or an amino group-containing compound, or impregnating / drying it, the reaction is further carried out at a temperature of 100 to 1000 ° C. in an inert atmosphere. Immobilization by heat treatment can also be suitably applied to the present invention.
また、本発明では炭素材料のミクロ孔を導入し、その容積とミクロ孔サイズを制御することが本質的に重要である。ミクロ孔の導入方法に関して、本発明は何ら制限するものではないが、例示するならば、いわゆる炭素材料の賦活を適用することが出来る。賦活の具体的方法は何ら問わないが、例示するならば、水蒸気賦活、炭酸ガス賦活、アルカリ金属賦活、塩化亜鉛賦活などを挙げることができる。ミクロ孔の容積・サイズの制御は、炭素材料の結晶性に応じて、賦活条件の強弱により制御可能である。 In the present invention, it is essentially important to introduce micropores in the carbon material and control the volume and micropore size. The present invention is not limited in any way with respect to the method for introducing micropores, but so-called carbon material activation can be applied. Although the specific method of activation is not ask | required at all, if illustrated, water vapor activation, carbon dioxide gas activation, alkali metal activation, zinc chloride activation etc. can be mentioned. Control of the volume and size of the micropores can be controlled by the strength of the activation conditions according to the crystallinity of the carbon material.
（触媒の金属種）
本発明は、固体高分子電解質形燃料電池用の触媒に適用する担体を中心技術とするものであり、触媒能を有する金属種は特に限定されるものではなく、一般的に適用される白金、白金と他の金属成分とを複合化した合金などを適用することが可能である。本発明の触媒をカソードに適用する場合の金属種としては、白金、或いは白金合金を例示することが可能である。白金と合金化させる金属元素として、３ｄ、４ｄ、５ｄ族の金属元素が好適である。５ｄ族の金属元素は白金の５ｄ電子の移動先としての機能では３ｄ、４ｄ元素よりも弱いと推察されるが、一方、固体高分子形燃料電池の電極反応の環境での金属の腐食溶解という観点からは、５ｄ元素と白金との合金化は白金の腐食を抑制するという観点から有効な合金元素である。前記金属元素の中でも、遷移金属元素がより好ましい。
(Metal species of catalyst)
The present invention is centered on a carrier applied to a catalyst for a solid polymer electrolyte fuel cell, and the metal species having catalytic ability is not particularly limited, and is generally applied platinum, An alloy in which platinum and other metal components are combined can be used. Examples of the metal species in the case where the catalyst of the present invention is applied to the cathode include platinum or a platinum alloy. As the metal element to be alloyed with platinum, 3d, 4d, and 5d group metal elements are preferable. The 5d group metal element is presumed to be weaker than the 3d and 4d elements in the function of platinum as a 5d electron transfer destination. On the other hand, the metal corrosion and dissolution in the electrode reaction environment of the polymer electrolyte fuel cell From the viewpoint, alloying of the 5d element and platinum is an effective alloy element from the viewpoint of suppressing platinum corrosion. Among the metal elements, transition metal elements are more preferable.
特に、カソード反応への本発明の適用に好適な白金以外の金属元素としては、本発明者らが鋭意検討の結果、Ｖ、Ｃｒ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｍｏ、Ｒｕ、Ｒｈ、Ｐｄ、Ａｇ、Ｒｅ、Ｉｒ、Ａｕの中から選ばれる少なくとも１種以上が好ましい。更に好ましくは、Ｃｒ、Ｆｅ、Ｃｏ、Ｎｉ、Ｒｈ、Ｐｄ、Ｉｒの中から選ばれる少なくとも1種以上である。電子論的に確固たる第一原理的な理論的裏づけはないが、前記金属元素は、白金の５ｄ電子を適度に減少させる効果が高く、そのために酸素還元反応における触媒活性を高めると考えられる。 In particular, as a metal element other than platinum suitable for application of the present invention to the cathode reaction, the present inventors have intensively studied, and as a result, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Rh At least one selected from Pd, Ag, Re, Ir, and Au is preferable. More preferably, it is at least one selected from Cr, Fe, Co, Ni, Rh, Pd, and Ir. Although there is no first-principles theoretical support that is firmly established in terms of electron theory, it is considered that the metal element has a high effect of moderately reducing the 5d electrons of platinum, and thus enhances the catalytic activity in the oxygen reduction reaction.
他方、本発明の触媒はアノード反応にも効果的に適用することができる。アノード反応への白金の適用課題は、炭化水素から水素を製造する際に副生する一酸化炭素によって白金触媒表面が強固に被覆されることに起因する水素酸化反応の阻害（一酸化炭素による被毒）、或いは、メタノール燃料電池においてメタノール酸化反応時のメタノール酸化過程で生成する中間体などに起因する白金表面の被毒（被覆）である。アノード反応の被毒対策の基本指針は、白金表面に形成される一酸化炭素などを酸化燃焼させるもので、そのための酸素源を合金元素上に形成するというもので、例えばＲｕ（ルテニウム）と白金との合金の場合には、Ｒｕ原子表面に形成される水酸基が酸素源となる。その他、アノードの耐被毒機能を持つ合金として、Ｐｔ−Ｆｅ、Ｐｔ−Ｍｏなどを例示することができる。 On the other hand, the catalyst of the present invention can also be effectively applied to the anode reaction. The problem of applying platinum to the anodic reaction is to inhibit the hydrogen oxidation reaction caused by carbon monoxide produced as a by-product when hydrocarbons are produced from hydrocarbons. Poison) or poisoning (coating) of the platinum surface caused by an intermediate produced in the methanol oxidation process during the methanol oxidation reaction in a methanol fuel cell. The basic guideline for the poisoning countermeasure of the anode reaction is to oxidize and burn carbon monoxide formed on the platinum surface, and to form an oxygen source for that purpose on the alloy element. For example, Ru (ruthenium) and platinum In the case of the alloy, the hydroxyl group formed on the Ru atom surface becomes the oxygen source. In addition, Pt—Fe, Pt—Mo, and the like can be exemplified as an alloy having an anode poisoning resistance function.
（担持量）
触媒金属微粒子の炭素担体上への担持量は、金属換算で１０質量%以上８０質量%以下が好ましい。１０質量%未満では、実用上必要な出力電圧を得るための触媒層の厚さが厚くなり過ぎるために過電圧が大きくなってしまうことがある。また、８０質量%を超える担持量では触媒層が薄過ぎるため大電流密度の負荷運転時に正極で生成する水によるガス拡散孔の閉塞を生じやすく安定した燃料電池の運転に支障をきたしてしまう場合がある。好ましくは、２０質量%以上８０質量%以下であり、更に好ましくは、２０質量%以上６０質量%以下である。
(Loading amount)
The amount of catalyst metal fine particles supported on the carbon support is preferably 10% by mass or more and 80% by mass or less in terms of metal. If it is less than 10% by mass, the overvoltage may increase because the thickness of the catalyst layer for obtaining a practically required output voltage becomes too thick. In addition, if the loading amount exceeds 80% by mass, the catalyst layer is too thin, and gas diffusion holes are likely to be clogged with water generated at the positive electrode during load operation with a large current density, which may hinder stable fuel cell operation. There is. Preferably, it is 20 mass% or more and 80 mass% or less, More preferably, it is 20 mass% or more and 60 mass% or less.
（触媒金属微粒子の担持方法）
本発明において規定される炭素材料表面に金属微粒子を担持する方法は特に制限されるものではない。具体的に金属微粒子の担持方法を例示するならば、塩化白金酸等の金属塩化物や、金属硝酸塩、アセチルアセトナートなどの金属錯体を、アルコール類、フェノール類、クエン酸類、ケトン類、アルデヒド類、カルボン酸類及びエーテル類、ボロンハイドライド、ヒドラジンなどから選ばれる還元剤によって還元し、炭素材料表面に液相で吸着させることによって、白金を主成分とした微粒子を炭素担体に担持するのが好ましい。その際に、水酸化ナトリウムなどを加えてｐＨを調節し、更に、微粒子の凝集を妨げるためにポリビニルピロリドンなどの保護剤を添加するのが好ましい。
(Supporting method of catalyst metal fine particles)
The method for supporting the metal fine particles on the surface of the carbon material defined in the present invention is not particularly limited. Specific examples of the method for supporting metal fine particles include metal chlorides such as chloroplatinic acid, metal complexes such as metal nitrate and acetylacetonate, alcohols, phenols, citric acids, ketones, and aldehydes. It is preferable that fine particles mainly composed of platinum are supported on a carbon carrier by reduction with a reducing agent selected from carboxylic acids and ethers, boron hydride, hydrazine and the like, and adsorption onto the surface of the carbon material in a liquid phase. At that time, it is preferable to adjust the pH by adding sodium hydroxide or the like, and to add a protective agent such as polyvinylpyrrolidone in order to prevent aggregation of fine particles.
微粒子の凝集・粒子の成長と炭素材料への吸着とは競合反応であるから、炭素材料の吸着速度を高めることが有効であり、そのための合成指針として、炭素担体の表面積を大きくする、或いは、微粒子の液相での密度を小さくして微粒子の会合頻度を下げることが重要である。 Aggregation of fine particles / growth of particles and adsorption to the carbon material are competitive reactions, so it is effective to increase the adsorption rate of the carbon material, and as a synthesis guide for that purpose, the surface area of the carbon support is increased, or It is important to reduce the density of the fine particles in the liquid phase to reduce the association frequency of the fine particles.
また、予め金属成分の前駆体を吸着させた炭素材料を気相での還元により触媒金属微粒子として炭素材料表面に析出させることも可能であるし、また、金属前駆体の溶液と炭素材料との懸濁液を気相中で急速加熱し、金属前駆体を気相で還元して触媒金属微粒子を生成させると同時に炭素材料表面に担持させる方法を適用することも可能である。 It is also possible to deposit a carbon material on which a precursor of a metal component has been adsorbed in advance on the surface of the carbon material as catalytic metal fine particles by reduction in a gas phase. It is also possible to apply a method in which the suspension is rapidly heated in the gas phase, and the metal precursor is reduced in the gas phase to produce catalytic metal fine particles and simultaneously supported on the carbon material surface.
（燃料電池用電極の製造方法）
本発明の触媒を用いて構成される電極は、電極の構成材料である電解質材料の種類や形態、電極構成に必要なバインダー材料の種類・構造によらず触媒の効果を発揮するものであって、これら電極構成材料は特に限定されるものではない。
(Method for producing fuel cell electrode)
The electrode configured using the catalyst of the present invention exhibits the effect of the catalyst regardless of the type and form of the electrolyte material that is a constituent material of the electrode, and the type and structure of the binder material required for the electrode configuration. These electrode constituent materials are not particularly limited.
本発明に使用される電解質膜や触媒層中に使用される電解質材料は、リン酸基、スルホン酸基等を導入した高分子、例えば、パーフルオロスルホン酸ポリマーやベンゼンスルホン酸が導入されたポリマー等を挙げることができるが、高分子に限定するものではなく、無機系材料との複合化膜、無機-有機ハイブリッド系の電解質膜等を使用した燃料電池に使用しても差し支えない。特に好適な作動温度範囲を例示するならば、常温〜１５０℃の範囲内で作動する燃料電池が好ましい。 The electrolyte material used in the electrolyte membrane or catalyst layer used in the present invention is a polymer in which a phosphoric acid group, a sulfonic acid group or the like is introduced, such as a polymer in which perfluorosulfonic acid polymer or benzenesulfonic acid is introduced. However, the present invention is not limited to the polymer, and may be used for a fuel cell using a composite membrane with an inorganic material, an inorganic-organic hybrid electrolyte membrane, or the like. If a particularly preferable operating temperature range is exemplified, a fuel cell that operates within a range of room temperature to 150 ° C. is preferable.
（燃料電池）
本発明の燃料電池用電極で、電解質膜を挟み、さらに、ガス拡散層、セパレーター、燃料ガス流路基板、酸素もしくは空気流路基板、ガスマニホールド等を組み合わせて固体高分子形燃料電池とすることができる。
(Fuel cell)
A fuel cell electrode according to the present invention sandwiches an electrolyte membrane, and further combines a gas diffusion layer, a separator, a fuel gas flow path substrate, an oxygen or air flow path substrate, a gas manifold, etc. to form a solid polymer fuel cell. Can do.
（炭素担体の製造法）
ＢＥＴ評価による比表面積８１５m2/gのカーボンブラックＡ、比表面積２２４m2/gのカーボンブラックＢを基に以下の種々の表面処理工程により表面官能基を制御した炭素材料を作製した。また、比較材として比表面積１２０m2/gのカーボンブラックＧを用意した。
(Method for producing carbon support)
Based on carbon black A having a specific surface area of 815 m 2 / g and carbon black B having a specific surface area of 224 m 2 / g by BET evaluation, a carbon material having surface functional groups controlled by the following various surface treatment steps was prepared. Further, carbon black G having a specific surface area of 120 m 2 / g was prepared as a comparative material .
＜硝酸酸化-熱処理＞
炭素材料Ａを濃硝酸（比重1.39）に分散し８０℃で攪拌しながら１時間処理した後、蒸留水で希釈・攪拌・濾過を繰り返し、濾液が中性になったところで濾過を終了し、９０℃で真空乾燥したものをANと記載する。ANをアルゴン雰囲気下で所定の温度（500、700℃）で１時間熱処理したものを、各々AN500、AN700と記載する。他の炭素材料に関しても、同様の処理をし、同様の表記とする。
<Nitric acid oxidation-heat treatment>
After carbon material A was dispersed in concentrated nitric acid (specific gravity 1.39) and treated at 80 ° C. with stirring for 1 hour, dilution, stirring and filtration were repeated with distilled water, and when the filtrate became neutral, the filtration was terminated. What was vacuum-dried at ℃ is described as AN. AN heat-treated at a predetermined temperature (500, 700 ° C. ) for 1 hour under an argon atmosphere is referred to as AN500 and AN700 , respectively. The same treatment is applied to other carbon materials, and the same notation is used.
＜アンモニアガス処理＞
炭素材料AN500をアンモニアガス雰囲気中５００℃で１時間処理したものをAN500Aと記載する。他の炭素材料に関しても同様の表記とする。
<Ammonia gas treatment>
A carbon material AN500 treated in an ammonia gas atmosphere at 500 ° C. for 1 hour is referred to as AN500A. The same notation is used for other carbon materials.
（白金担持）
上記の各種カーボンブラックを蒸留水に分散させ超音波処理し、アルゴンバブル３０分した後、攪拌しながら塩化白金酸水溶液とホルムアルデヒド水溶液を数時間かけてゆっくり滴下して白金微粒子をカーボンブラック上に担持させた。Ｐｔの担持率は約５０mass%でＰｔ粒子のＸ線回折による直径が３〜４nmの範囲になるように合成の条件を適宜検討した。
(Platinum supported)
Disperse the above various carbon blacks in distilled water, sonicate, and after 30 minutes of argon bubbles, slowly drop the chloroplatinic acid aqueous solution and formaldehyde aqueous solution over several hours while stirring to support platinum fine particles on the carbon black I let you. The conditions of synthesis were appropriately examined so that the Pt loading was about 50 mass% and the diameter of the Pt particles by X-ray diffraction was in the range of 3 to 4 nm.
上記の炭素担体の窒素ガス吸着測定による比表面積（SBET）、ミクロ孔容積（Vmicro）、ミクロ孔細孔径（Dmicro）、塩基性官能基量（B/SBET）、全酸度（TA/SBET）を表１にまとめて示した。 Specific surface area (S BET ), micropore volume (V micro ), micropore pore diameter (D micro ), basic functional group content (B / S BET ), total acidity (TA / S BET ) is summarized in Table 1.
（炭素材料の各種物性値の測定）
ここで本発明の炭素表面の官能基量は、下記の方法により測定するものとする：
（１）窒素ガス吸着による各種指標：
ＳBET、Ｖmicro、Ｄmicro；窒素ガスの吸着等温測定から、ＢＥＴ法による比表面積ＳBET、ｔプロット解析により求めたミクロポア（直径2nm以下の細孔）の面積Ｓmicroと、スリット形状のミクロ孔を仮定して算出したミクロポア径Ｄmicroである。ガス吸着測定には、日本ベル株式会社製BELSORP 36を用い、ｔプロット解析は装置に付属の解析プログラムを使用して上記の物性値を算出した。
(Measurement of various physical properties of carbon materials)
Here, the functional group amount on the carbon surface of the present invention is measured by the following method:
(1) Various indicators by nitrogen gas adsorption:
S BET , V micro , D micro ; Specific surface area S BET by the BET method from nitrogen gas adsorption isothermal measurement, area S micro of micropores (pores with a diameter of 2 nm or less) obtained by t plot analysis, and slit-shaped micro This is a micropore diameter D micro calculated assuming a hole. For gas adsorption measurement, BELSORP 36 manufactured by Nippon Bell Co., Ltd. was used, and for t plot analysis, the above physical property values were calculated using an analysis program attached to the apparatus.
（２）塩基性官能基量：
予め９０℃で３０分以上真空乾燥したカーボンブラック０．５gを精秤し１００mLの三角フラスコへ入れる。そこへ1/100規定ＨＣｌ溶液を５０mL注入し、カーボンブラックを充分に分散させ、密栓状態で２時間振とうする。振とう後の溶液を加圧濾過し、カーボンブラックと反応後のＨＣｌ溶液とに分離する。反応後のＨＣｌ溶液を１０mLとり、1/100規定のＮａＯＨ溶液で中和滴定し、滴下したＮａＯＨ溶液量からカーボンブラック１g当たりのＨＣｌ吸着量を算出し、これを塩基性官能基量とする。
(2) Basic functional group amount:
Precisely weigh 0.5 g of carbon black previously vacuum-dried at 90 ° C. for 30 minutes or more into a 100 mL Erlenmeyer flask. 50 mL of 1/100 N HCl solution is poured into it, and carbon black is sufficiently dispersed, and shaken in a sealed state for 2 hours. The solution after shaking is filtered under pressure and separated into carbon black and an HCl solution after reaction. Take 10 mL of the HCl solution after the reaction, neutralize and titrate with 1/100 N NaOH solution, calculate the HCl adsorption amount per gram of carbon black from the added NaOH solution amount, and use this as the basic functional group amount.
（３）酸性官能基量：
予め９０℃で３０分以上真空乾燥したカーボンブラック０．５gを精秤し１００mLの三角フラスコへ入れる。そこへ1/100規定ＮａＯＨ溶液を５０mL注入し、カーボンブラックを充分に分散させ、密栓状態で２時間振とうする。振とう後の溶液を加圧濾過し、カーボンブラックと反応後のＮａＯＨ溶液とに分離する。反応後のＮａＯＨ溶液を１０mLとり、1/100規定のＨＣｌ溶液で中和滴定し、滴下したＨＣｌ溶液量からカーボンブラック１g当たりのＮａＯＨ吸着量を算出し、これを酸性官能基量とする。
(3) Amount of acidic functional group:
Precisely weigh 0.5 g of carbon black previously vacuum-dried at 90 ° C. for 30 minutes or more into a 100 mL Erlenmeyer flask. 50 mL of 1/100 N NaOH solution is poured into it, and carbon black is sufficiently dispersed, and shaken for 2 hours in a sealed state. The solution after shaking is filtered under pressure to separate the carbon black and the reacted NaOH solution. Take 10 mL of the NaOH solution after the reaction, neutralize and titrate with 1/100 N HCl solution, calculate the amount of adsorbed NaOH per 1 g of carbon black from the amount of HCl solution added, and use this as the amount of acidic functional groups.
（触媒層電極・膜／電極接合体（Membrane Electrode Assembly, MEA）の作製）
各々の触媒を用いて下記の工程で触媒層電極を作製した。
予め乳鉢で充分に粉砕した触媒粉に５%濃度のナフィオン溶液(アルドリッチ製)を白金触媒の質量に対してナフィオン固形分の質量が２倍になるように加え、軽く撹拌後、超音波で充分に分散処理した。更に、この分散液を強く攪拌した状態で、触媒とナフィオンを合わせた固形分濃度が６質量%となるように酢酸ブチルを加え、触媒スラリーを作製した。
(Production of catalyst layer electrode / membrane / electrode assembly (Membrane Electrode Assembly, MEA))
Using each catalyst, a catalyst layer electrode was prepared in the following steps .
Add 5% Nafion solution (manufactured by Aldrich) to the catalyst powder that has been sufficiently ground in a mortar so that the mass of Nafion solids is twice the mass of the platinum catalyst. Distributed processing. Further, butyl acetate was added in a state where the dispersion was vigorously stirred so that the solid content concentration of the catalyst and Nafion was 6% by mass to prepare a catalyst slurry.
別容器中でカーボンブラックに酢酸ブチルを加え、超音波で十分に分散させて、カーボンブラックが６質量%のカーボンブラックスラリーを作製した。触媒スラリーとカーボンブラックスラリーを質量比８：２で混合した後、十分攪拌し、触媒層スラリーとした。 In a separate container, butyl acetate was added to carbon black and sufficiently dispersed with ultrasonic waves to prepare a carbon black slurry containing 6% by mass of carbon black. The catalyst slurry and the carbon black slurry were mixed at a mass ratio of 8: 2, and then sufficiently stirred to obtain a catalyst layer slurry.
市販のカーボンクロス（ElectroChem社製EC-CC1-060）を準備し、これを５%に希釈したテフロン（登録商標）分散液中に浸漬した後、乾燥し、さらにアルゴン気流中で３４０℃に昇温してガス拡散層を作製した。また、カーボンブラック１gにエタノール９９gを加え、ボールミルでカーボンブラックを粉砕し、一次分散液を作った。その後、一次分散液を攪拌しながら30%テフロン（登録商標）分散液０．８３３gを少しずつ滴下し、マイクロポア層スラリーを作製した。このスラリーを先に作成したガス拡散繊維層の片面にスプレーを用いて塗布し、アルゴン気流中８０℃で乾燥した後に３４０℃に昇温して、ガス拡散繊維層とマイクロポア層が積層したガス拡散層を作製した。 A commercially available carbon cloth (Electro-Chem EC-CC1-060) was prepared, dipped in a Teflon (registered trademark) dispersion diluted to 5%, dried, and further heated to 340 ° C. in an argon stream. A gas diffusion layer was produced by heating. Further, 99 g of ethanol was added to 1 g of carbon black, and the carbon black was pulverized with a ball mill to prepare a primary dispersion. Thereafter, 0.833 g of 30% Teflon (registered trademark) dispersion was added dropwise little by little while stirring the primary dispersion to prepare a micropore layer slurry. The slurry was applied to one side of the previously prepared gas diffusion fiber layer using a spray, dried at 80 ° C. in an argon stream, heated to 340 ° C., and a gas in which the gas diffusion fiber layer and the micropore layer were laminated. A diffusion layer was prepared.
触媒層スラリーをガス拡散層のマイクロポア層の上にスプレーで塗布し、８０℃のアルゴン気流中で１時間乾燥し、固体高分子形燃料電池用電極を得た。なお、各々の電極は白金使用量が０．１５mg/cm2となるようにスプレー等の条件を設定した。白金使用量は、スプレー塗布前後の電極の乾燥質量を測定し、その差から計算して求めた。 The catalyst layer slurry was applied on the micropore layer of the gas diffusion layer by spraying and dried in an argon stream at 80 ° C. for 1 hour to obtain a polymer electrolyte fuel cell electrode. In addition, conditions such as spraying were set so that the amount of platinum used for each electrode was 0.15 mg / cm 2 . The amount of platinum used was determined by measuring the dry mass of the electrode before and after spray coating and calculating the difference.
さらに、得られた固体高分子形燃料電池用電極から２．５cm角の大きさを切り取り、アノード用電極、或いは、カソード用電極とした。アノード電極とカソード電極で電解質膜（ナフィオン112）をはさみ、１３０℃、総加圧０．６２５tで３分間ホットプレスを行い、ＭＥＡを作製した。 Further, a 2.5 cm square size was cut out from the obtained polymer electrolyte fuel cell electrode to obtain an anode electrode or a cathode electrode. The electrolyte membrane (Nafion 112) was sandwiched between the anode electrode and the cathode electrode, and hot pressing was performed at 130 ° C. and a total pressure of 0.625 t for 3 minutes to prepare an MEA.
（セル評価法）
得られたＭＥＡは、それぞれ燃料電池測定装置に組み込み、電池性能測定を行った。電池性能測定は、セル端子間電圧を開放電圧(通常0.9〜1.0V程度)から０．２Vまで段階的に変化させ、セル端子間電圧が０．８Vのときに流れる電流密度を測定した。ガスは、カソードに空気、アノードに純水素を、利用率がそれぞれ５０%と８０%となるように供給し、それぞれのガス圧は、セル下流に設けられた背圧弁で０．１MPaに圧力調整した。セル温度は８０℃に設定し、供給する空気と純水素は、それぞれ８０℃と９０℃に保温された蒸留水中でバブリングを行い、加湿した。
(Cell evaluation method)
Each of the obtained MEAs was incorporated into a fuel cell measurement device, and the cell performance was measured. In the battery performance measurement, the voltage between the cell terminals was changed stepwise from the open voltage (usually about 0.9 to 1.0 V) to 0.2 V, and the current density flowing when the cell terminal voltage was 0.8 V was measured. The gas is supplied to the cathode with air and pure hydrogen to the anode so that the utilization rates are 50% and 80%, respectively, and the pressure of each gas is adjusted to 0.1 MPa by a back pressure valve provided downstream of the cell. did. The cell temperature was set to 80 ° C., and the supplied air and pure hydrogen were bubbled in distilled water kept at 80 ° C. and 90 ° C., respectively, and humidified.
表２に、表1に記載した各々の触媒を用いて上述の方法で作製した電極をアノードとカソードに組合わせて作製したＭＥＡの評価結果をまとめて示した。
表２から、本発明で規定する触媒をカソードに用いたＭＥＡは、明らかに高い電池性能を発現していることがわかる。
Table 2 summarizes the evaluation results of MEAs prepared by combining the electrodes prepared by the above-described method using the respective catalysts described in Table 1 with an anode and a cathode.
From Table 2, it can be seen that MEA using the catalyst defined in the present invention for the cathode clearly exhibits high battery performance.
Claims (4)
（ａ）窒素吸着比表面積（SBET；m2/g）：２００≦ＳBET≦８２２
（ｂ）塩基性官能基量（B；meq/g）とＳBETの比：０．５≦Ｂ／ＳBET≦２．６８
（ｃ）酸性官能基量（TA；meq/g）とＳBETの比：０．０５≦TA／ＳBET≦２
（ｄ）塩基性官能基量Ｂと酸性官能基量TAの比：２≦Ｂ／TA≦１５ 1. A catalyst for a polymer electrolyte fuel cell electrode, comprising a carbon material carrying metal fine particles, wherein the carbon material simultaneously satisfies the following formulas (a) to (d):
(A) Nitrogen adsorption specific surface area (S BET ; m 2 / g): 200 ≦ S BET ≦ 822
(B) Ratio of basic functional group amount (B; meq / g) to S BET : 0.5 ≦ B / S BET ≦ 2.68
(C) Ratio of acidic functional group amount (TA; meq / g) to S BET : 0.05 ≦ TA / S BET ≦ 2
(D) Ratio of basic functional group amount B to acidic functional group amount TA: 2 ≦ B / TA ≦ 15
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007108547A JP5121290B2 (en) | 2007-04-17 | 2007-04-17 | Catalyst for polymer electrolyte fuel cell electrode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007108547A JP5121290B2 (en) | 2007-04-17 | 2007-04-17 | Catalyst for polymer electrolyte fuel cell electrode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2008269850A JP2008269850A (en) | 2008-11-06 |
| JP5121290B2 true JP5121290B2 (en) | 2013-01-16 |
Family
ID=40049119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007108547A Active JP5121290B2 (en) | 2007-04-17 | 2007-04-17 | Catalyst for polymer electrolyte fuel cell electrode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5121290B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107431212A (en) * | 2015-02-18 | 2017-12-01 | 新日铁住金株式会社 | Catalyst carrier carbon material, solid polymer fuel cell catalyst, the manufacture method of solid polymer fuel cell and catalyst carrier carbon material |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2910372C (en) * | 2013-04-25 | 2018-02-27 | Nissan Motor Co., Ltd. | Catalyst and electrode catalyst layer, membrane electrode assembly, and fuel cell using the catalyst |
| WO2014175098A1 (en) | 2013-04-25 | 2014-10-30 | 日産自動車株式会社 | Catalyst, electrode catalyst layer using said catalyst, membrane electrode assembly, and fuel cell |
| EP2990109B1 (en) * | 2013-04-25 | 2019-10-23 | Nissan Motor Co., Ltd | Catalyst and electrode catalyst layer for fuel cell having the catalyst |
| CA2910237C (en) | 2013-04-25 | 2019-01-15 | Nissan Motor Co., Ltd. | Catalyst and manufacturing method thereof, and electrode catalyst layer using the catalyst |
| JP6279366B2 (en) * | 2014-03-14 | 2018-02-14 | Ｊｘｔｇエネルギー株式会社 | Electrode material, membrane electrode assembly, fuel cell stack, and method for producing electrode material |
| JP6271332B2 (en) * | 2014-05-08 | 2018-01-31 | 株式会社ブリヂストン | Method for producing wet masterbatch and wet masterbatch produced by the method |
| WO2016067876A1 (en) * | 2014-10-29 | 2016-05-06 | 日産自動車株式会社 | Electrode catalyst for fuel cell, electrode catalyst layer for fuel cell, method for producing same, and membrane electrode assembly and fuel cell using catalyst layer |
| CA2966176C (en) | 2014-10-29 | 2019-12-31 | Nissan Motor Co., Ltd. | Electrode catalyst layer for fuel cell, method for producing the same, and membrane electrode assembly and fuel cell using the catalyst layer |
| JP7366892B2 (en) * | 2017-11-09 | 2023-10-23 | ザ ボード オブ トラスティーズ オブ ザ レランド スタンフォード ジュニア ユニバーシティー | Ultrathin electrochemical catalyst on catalyst support for proton exchange membrane fuel cells |
| EP3767723B1 (en) | 2018-03-16 | 2024-08-21 | Cataler Corporation | Electrode catalyst for fuel cell, and fuel cell using same |
| KR102322106B1 (en) * | 2019-04-23 | 2021-11-04 | 건국대학교 산학협력단 | Highly dispersed platinum supported porous carbon sheet, cathode catalyst comprising the same, and MEA for PEMFC using the same |
| KR102440780B1 (en) * | 2020-10-16 | 2022-09-06 | 비나텍주식회사 | Method for manufacturing platinum group fuel cell catalyst support |
| WO2022172947A1 (en) * | 2021-02-09 | 2022-08-18 | エヌ・イー ケムキャット株式会社 | Method of producing electrode catalyst, method of producing gas diffusion electrode, and method of producing membrane/electrode assembly |
| WO2022172948A1 (en) * | 2021-02-09 | 2022-08-18 | エヌ・イー ケムキャット株式会社 | Method for producing electrode catalyst, method for producing gas diffusion electrode, and method for producing film-electrode joint body |
| CN114094113A (en) * | 2021-11-05 | 2022-02-25 | 中自环保科技股份有限公司 | Carbon carrier for hydrogen fuel cell, preparation method and prepared cell catalyst |
Family Cites Families (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1084477A (en) * | 1975-07-22 | 1980-08-26 | Brian D. Mcnicol | Catalysts supported on at least partially polycrystalline graphite |
| JP2955938B2 (en) * | 1989-04-20 | 1999-10-04 | 東洋紡績株式会社 | Carbon-based electrode materials for electrolytic cells |
| JP2879649B2 (en) * | 1994-12-05 | 1999-04-05 | 工業技術院長 | Method for producing platinum-based catalyst |
| US6277513B1 (en) * | 1999-04-12 | 2001-08-21 | General Motors Corporation | Layered electrode for electrochemical cells |
| US6399202B1 (en) * | 1999-10-12 | 2002-06-04 | Cabot Corporation | Modified carbon products useful in gas diffusion electrodes |
| JP4721539B2 (en) * | 2001-03-26 | 2011-07-13 | パナソニック株式会社 | Fuel cell electrode catalyst and method for producing the same |
| JP4856838B2 (en) * | 2002-11-19 | 2012-01-18 | 株式会社豊田中央研究所 | Nitrogen-containing carbon-based porous body and method for producing the same |
| JP2005056686A (en) * | 2003-08-05 | 2005-03-03 | National Institute Of Advanced Industrial & Technology | Cathode of solid polymer fuel cell |
| JP4645015B2 (en) * | 2003-10-24 | 2011-03-09 | 株式会社日立製作所 | Catalyst material and fuel cell using the same |
| JP4533108B2 (en) * | 2004-11-25 | 2010-09-01 | 新日本製鐵株式会社 | Electrode for polymer electrolyte fuel cell |
| KR100919326B1 (en) * | 2004-04-22 | 2009-09-25 | 신닛뽄세이테쯔 카부시키카이샤 | Fuel cell and gas diffusion electrode for fuel cell |
| JP4587027B2 (en) * | 2004-06-07 | 2010-11-24 | 株式会社豊田中央研究所 | Nitrogen-containing carbon-based composite material |
| JP2006179427A (en) * | 2004-12-24 | 2006-07-06 | Toyota Motor Corp | Electrode catalyst for fuel cell, and the fuel cell |
| JP2006209999A (en) * | 2005-01-25 | 2006-08-10 | Gs Yuasa Corporation:Kk | Electrode for polymer electrolyte fuel cell and its manufacturing method |
| JP4939005B2 (en) * | 2005-07-29 | 2012-05-23 | 関西熱化学株式会社 | Catalyst carrier and catalyst carrier for electrode catalyst of fuel cell |
-
2007
- 2007-04-17 JP JP2007108547A patent/JP5121290B2/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107431212A (en) * | 2015-02-18 | 2017-12-01 | 新日铁住金株式会社 | Catalyst carrier carbon material, solid polymer fuel cell catalyst, the manufacture method of solid polymer fuel cell and catalyst carrier carbon material |
| CN107431212B (en) * | 2015-02-18 | 2020-10-27 | 日铁化学材料株式会社 | Carbon material for catalyst support, catalyst for solid polymer fuel cell, and method for producing carbon material for catalyst support |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008269850A (en) | 2008-11-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5121290B2 (en) | Catalyst for polymer electrolyte fuel cell electrode | |
| Lee et al. | Progress in the synthesis of carbon nanotube-and nanofiber-supported Pt electrocatalysts for PEM fuel cell catalysis | |
| JP5294235B2 (en) | Electrode material | |
| US8409659B2 (en) | Nanowire supported catalysts for fuel cell electrodes | |
| Jukk et al. | Platinum nanoparticles supported on nitrogen-doped graphene nanosheets as electrocatalysts for oxygen reduction reaction | |
| JP5332429B2 (en) | Electrocatalyst | |
| KR100837396B1 (en) | Supported catalyst, method for preparing the same, cathode electrode comprising the same, and fuel cell comprising the electrode | |
| Bharti et al. | Surfactant assisted synthesis of Pt-Pd/MWCNT and evaluation as cathode catalyst for proton exchange membrane fuel cell | |
| JP2009532830A (en) | Compositions of nanoparticles and platinum particles containing metals or alloys for use in fuel cells. | |
| TWI464953B (en) | Membrane electrode and fuel cell using the same | |
| JP2009527890A (en) | Platinum and platinum-based alloy nanotubes used as electrocatalysts for fuel cells | |
| JP3643552B2 (en) | Catalyst for air electrode of solid polymer electrolyte fuel cell and method for producing the catalyst | |
| JP2010027364A (en) | Electrode catalyst for fuel cell and its manufacturing method | |
| JP2009009815A (en) | Electrode catalyst substrate, its manufacturing method, and solid polymer fuel cell | |
| Truong et al. | Functionalized carbon black supported silver (Ag/C) catalysts in cathode electrode for alkaline anion exchange membrane fuel cells | |
| Jayawickrama et al. | Enhanced platinum utilization efficiency of polymer-coated carbon black as an electrocatalyst in polymer electrolyte membrane fuel cells | |
| JP2003157857A (en) | Electrode catalyst body for fuel cell, air electrode for fuel cell using it, and evaluating method of its catalystic activity | |
| Wu et al. | Synthesis of hollow echinus-like Au@ PdAgNSs decorated reduced graphene oxide as an excellent electrocatalyst for enhanced ethanol electrooxidation | |
| US20100183945A1 (en) | Electrode catalyst for fuel cell, process for producing the same and solid polymer fuel cell comprising the same | |
| JP2008041498A (en) | Method of manufacturing catalyst support body for polymer electrolyte fuel cell, and polymer electrolyte fuel cell | |
| JP2016091878A (en) | Method for manufacturing electrode material, membrane-electrode assembly and fuel cell stack | |
| Dembinska et al. | Multi-walled carbon nanotube-supported tungsten oxide-containing multifunctional hybrid electrocatalytic system for oxygen reduction in acid medium | |
| JP2002015745A (en) | Solid polymer fuel cell | |
| Chen et al. | Pt nanoparticles supported on non-carbon titanium chromium nitride nanotubes with high activity and durability for methanol oxidation reaction | |
| Lafuente et al. | Single-walled carbon nanotube-supported platinum nanoparticles as fuel cell electrocatalysts |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20091221 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20120416 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20120424 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20120625 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20120724 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20120903 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20121002 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20121023 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20151102 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 Ref document number: 5121290 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| S111 | Request for change of ownership or part of ownership |
Free format text: JAPANESE INTERMEDIATE CODE: R313117 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |