JP2015199066A - Exhaust gas purification device for internal combustion engine, production method of the same and paint for producing exhaust gas purification device - Google Patents
Exhaust gas purification device for internal combustion engine, production method of the same and paint for producing exhaust gas purification device Download PDFInfo
- Publication number
- JP2015199066A JP2015199066A JP2015070154A JP2015070154A JP2015199066A JP 2015199066 A JP2015199066 A JP 2015199066A JP 2015070154 A JP2015070154 A JP 2015070154A JP 2015070154 A JP2015070154 A JP 2015070154A JP 2015199066 A JP2015199066 A JP 2015199066A
- Authority
- JP
- Japan
- Prior art keywords
- particles
- exhaust gas
- catalyst
- silicon carbide
- catalyst particles
- 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.)
- Pending
Links
- 238000000746 purification Methods 0.000 title claims abstract description 124
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 94
- 239000003973 paint Substances 0.000 title claims description 104
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- 239000002245 particle Substances 0.000 claims abstract description 474
- 239000003054 catalyst Substances 0.000 claims abstract description 306
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims abstract description 139
- 229910010271 silicon carbide Inorganic materials 0.000 claims abstract description 139
- 239000011148 porous material Substances 0.000 claims abstract description 132
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 118
- 239000002923 metal particle Substances 0.000 claims abstract description 79
- 239000000919 ceramic Substances 0.000 claims abstract description 11
- 239000000758 substrate Substances 0.000 claims description 120
- 238000000034 method Methods 0.000 claims description 73
- 239000002243 precursor Substances 0.000 claims description 31
- 239000011164 primary particle Substances 0.000 claims description 28
- 239000002612 dispersion medium Substances 0.000 claims description 20
- 239000010970 precious metal Substances 0.000 claims description 9
- 230000000717 retained effect Effects 0.000 claims description 7
- 239000000463 material Substances 0.000 abstract description 66
- 238000010276 construction Methods 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 219
- 238000005192 partition Methods 0.000 description 102
- 239000010410 layer Substances 0.000 description 79
- 239000013618 particulate matter Substances 0.000 description 62
- 238000000576 coating method Methods 0.000 description 38
- 238000010438 heat treatment Methods 0.000 description 38
- 239000011248 coating agent Substances 0.000 description 34
- 230000008569 process Effects 0.000 description 33
- 230000000052 comparative effect Effects 0.000 description 28
- 239000012298 atmosphere Substances 0.000 description 26
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 26
- 239000002585 base Substances 0.000 description 19
- 238000011156 evaluation Methods 0.000 description 18
- 230000003197 catalytic effect Effects 0.000 description 17
- 239000010419 fine particle Substances 0.000 description 17
- 238000011282 treatment Methods 0.000 description 17
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 15
- 239000012300 argon atmosphere Substances 0.000 description 13
- 230000003647 oxidation Effects 0.000 description 13
- 238000007254 oxidation reaction Methods 0.000 description 13
- 239000006185 dispersion Substances 0.000 description 12
- 229910052697 platinum Inorganic materials 0.000 description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 11
- 239000002904 solvent Substances 0.000 description 11
- 239000003795 chemical substances by application Substances 0.000 description 10
- 230000000694 effects Effects 0.000 description 10
- 239000000126 substance Substances 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 7
- -1 chlorides Chemical compound 0.000 description 7
- 239000000446 fuel Substances 0.000 description 7
- 229920001477 hydrophilic polymer Polymers 0.000 description 7
- 229910052763 palladium Inorganic materials 0.000 description 7
- 238000005245 sintering Methods 0.000 description 7
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 6
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- 229910002091 carbon monoxide Inorganic materials 0.000 description 6
- 238000002347 injection Methods 0.000 description 6
- 239000007924 injection Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 239000011347 resin Substances 0.000 description 6
- 229920005989 resin Polymers 0.000 description 6
- 239000010948 rhodium Substances 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 5
- 150000001298 alcohols Chemical class 0.000 description 5
- 229910021529 ammonia Inorganic materials 0.000 description 5
- 239000011247 coating layer Substances 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- 229920001600 hydrophobic polymer Polymers 0.000 description 5
- 229910052741 iridium Inorganic materials 0.000 description 5
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 5
- 230000001590 oxidative effect Effects 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 229910052703 rhodium Inorganic materials 0.000 description 5
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 229910004298 SiO 2 Inorganic materials 0.000 description 4
- DOSXDVYWNFUSBU-UHFFFAOYSA-N [O-][N+](=O)[Pt][N+]([O-])=O Chemical compound [O-][N+](=O)[Pt][N+]([O-])=O DOSXDVYWNFUSBU-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000007598 dipping method Methods 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 238000011068 loading method Methods 0.000 description 4
- 239000011325 microbead Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000000178 monomer Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 229920000642 polymer Polymers 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 150000003839 salts Chemical class 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 3
- ZNQVEEAIQZEUHB-UHFFFAOYSA-N 2-ethoxyethanol Chemical compound CCOCCO ZNQVEEAIQZEUHB-UHFFFAOYSA-N 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 description 3
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 230000002776 aggregation Effects 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 150000004985 diamines Chemical class 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- XPFVYQJUAUNWIW-UHFFFAOYSA-N furfuryl alcohol Chemical compound OCC1=CC=CO1 XPFVYQJUAUNWIW-UHFFFAOYSA-N 0.000 description 3
- 150000004676 glycans Chemical class 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 150000002576 ketones Chemical class 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 229910052754 neon Inorganic materials 0.000 description 3
- GKAOGPIIYCISHV-UHFFFAOYSA-N neon atom Chemical compound [Ne] GKAOGPIIYCISHV-UHFFFAOYSA-N 0.000 description 3
- 229910052762 osmium Inorganic materials 0.000 description 3
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 3
- 239000004926 polymethyl methacrylate Substances 0.000 description 3
- 229920001282 polysaccharide Polymers 0.000 description 3
- 239000005017 polysaccharide Substances 0.000 description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 description 3
- 239000003755 preservative agent Substances 0.000 description 3
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 3
- 235000018102 proteins Nutrition 0.000 description 3
- 102000004169 proteins and genes Human genes 0.000 description 3
- 108090000623 proteins and genes Proteins 0.000 description 3
- 229910052707 ruthenium Inorganic materials 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- 239000003381 stabilizer Substances 0.000 description 3
- 239000004094 surface-active agent Substances 0.000 description 3
- 229910052724 xenon Inorganic materials 0.000 description 3
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 3
- XNWFRZJHXBZDAG-UHFFFAOYSA-N 2-METHOXYETHANOL Chemical compound COCCO XNWFRZJHXBZDAG-UHFFFAOYSA-N 0.000 description 2
- POAOYUHQDCAZBD-UHFFFAOYSA-N 2-butoxyethanol Chemical compound CCCCOCCO POAOYUHQDCAZBD-UHFFFAOYSA-N 0.000 description 2
- SVTBMSDMJJWYQN-UHFFFAOYSA-N 2-methylpentane-2,4-diol Chemical compound CC(O)CC(C)(C)O SVTBMSDMJJWYQN-UHFFFAOYSA-N 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- 229920002472 Starch Polymers 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 239000002518 antifoaming agent Substances 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- 239000002178 crystalline material Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- SWXVUIWOUIDPGS-UHFFFAOYSA-N diacetone alcohol Chemical compound CC(=O)CC(C)(C)O SWXVUIWOUIDPGS-UHFFFAOYSA-N 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-N dimethylselenoniopropionate Natural products CCC(O)=O XBDQKXXYIPTUBI-UHFFFAOYSA-N 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- YLGXILFCIXHCMC-JHGZEJCSSA-N methyl cellulose Chemical compound COC1C(OC)C(OC)C(COC)O[C@H]1O[C@H]1C(OC)C(OC)C(OC)OC1COC YLGXILFCIXHCMC-JHGZEJCSSA-N 0.000 description 2
- 150000007522 mineralic acids Chemical class 0.000 description 2
- 150000007524 organic acids Chemical class 0.000 description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 2
- 230000002335 preservative effect Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000008107 starch Substances 0.000 description 2
- 235000019698 starch Nutrition 0.000 description 2
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- SBASXUCJHJRPEV-UHFFFAOYSA-N 2-(2-methoxyethoxy)ethanol Chemical compound COCCOCCO SBASXUCJHJRPEV-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- 229920000936 Agarose Polymers 0.000 description 1
- 229910000505 Al2TiO5 Inorganic materials 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 1
- 102000011632 Caseins Human genes 0.000 description 1
- 108010076119 Caseins Proteins 0.000 description 1
- 229920002101 Chitin Polymers 0.000 description 1
- 229920001661 Chitosan Polymers 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 102000008186 Collagen Human genes 0.000 description 1
- 108010035532 Collagen Proteins 0.000 description 1
- 229920002307 Dextran Polymers 0.000 description 1
- 239000004375 Dextrin Substances 0.000 description 1
- 229920001353 Dextrin Polymers 0.000 description 1
- 102000016942 Elastin Human genes 0.000 description 1
- 108010014258 Elastin Proteins 0.000 description 1
- 102000016359 Fibronectins Human genes 0.000 description 1
- 108010067306 Fibronectins Proteins 0.000 description 1
- 108010010803 Gelatin Proteins 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 240000007049 Juglans regia Species 0.000 description 1
- 235000009496 Juglans regia Nutrition 0.000 description 1
- 102000007547 Laminin Human genes 0.000 description 1
- 108010085895 Laminin Proteins 0.000 description 1
- 229920000057 Mannan Polymers 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 240000008042 Zea mays Species 0.000 description 1
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 1
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 125000000218 acetic acid group Chemical group C(C)(=O)* 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- WDJHALXBUFZDSR-UHFFFAOYSA-M acetoacetate Chemical compound CC(=O)CC([O-])=O WDJHALXBUFZDSR-UHFFFAOYSA-M 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 230000002421 anti-septic effect Effects 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 208000006673 asthma Diseases 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009530 blood pressure measurement Methods 0.000 description 1
- 235000011089 carbon dioxide Nutrition 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 239000000679 carrageenan Substances 0.000 description 1
- 229920001525 carrageenan Polymers 0.000 description 1
- 235000010418 carrageenan Nutrition 0.000 description 1
- 229940113118 carrageenan Drugs 0.000 description 1
- 239000005018 casein Substances 0.000 description 1
- BECPQYXYKAMYBN-UHFFFAOYSA-N casein, tech. Chemical compound NCCCCC(C(O)=O)N=C(O)C(CC(O)=O)N=C(O)C(CCC(O)=N)N=C(O)C(CC(C)C)N=C(O)C(CCC(O)=O)N=C(O)C(CC(O)=O)N=C(O)C(CCC(O)=O)N=C(O)C(C(C)O)N=C(O)C(CCC(O)=N)N=C(O)C(CCC(O)=N)N=C(O)C(CCC(O)=N)N=C(O)C(CCC(O)=O)N=C(O)C(CCC(O)=O)N=C(O)C(COP(O)(O)=O)N=C(O)C(CCC(O)=N)N=C(O)C(N)CC1=CC=CC=C1 BECPQYXYKAMYBN-UHFFFAOYSA-N 0.000 description 1
- 235000021240 caseins Nutrition 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 150000001805 chlorine compounds Chemical class 0.000 description 1
- 229920001436 collagen Polymers 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 235000005822 corn Nutrition 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001784 detoxification Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 235000019425 dextrin Nutrition 0.000 description 1
- XXJWXESWEXIICW-UHFFFAOYSA-N diethylene glycol monoethyl ether Chemical compound CCOCCOCCO XXJWXESWEXIICW-UHFFFAOYSA-N 0.000 description 1
- 229940075557 diethylene glycol monoethyl ether Drugs 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 238000003618 dip coating Methods 0.000 description 1
- 229920002549 elastin Polymers 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- UHESRSKEBRADOO-UHFFFAOYSA-N ethyl carbamate;prop-2-enoic acid Chemical compound OC(=O)C=C.CCOC(N)=O UHESRSKEBRADOO-UHFFFAOYSA-N 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000000499 gel Substances 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 229920000159 gelatin Polymers 0.000 description 1
- 235000019322 gelatine Nutrition 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 230000005802 health problem Effects 0.000 description 1
- 229940051250 hexylene glycol Drugs 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 238000007561 laser diffraction method Methods 0.000 description 1
- 210000004072 lung Anatomy 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 229920005615 natural polymer Polymers 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- 235000014571 nuts Nutrition 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 229910052574 oxide ceramic Inorganic materials 0.000 description 1
- 239000011224 oxide ceramic Substances 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- 239000001814 pectin Substances 0.000 description 1
- 229920001277 pectin Polymers 0.000 description 1
- 235000010987 pectin Nutrition 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920000083 poly(allylamine) Polymers 0.000 description 1
- 229920000172 poly(styrenesulfonic acid) Polymers 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229940005642 polystyrene sulfonic acid Drugs 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- KCTAWXVAICEBSD-UHFFFAOYSA-N prop-2-enoyloxy prop-2-eneperoxoate Chemical compound C=CC(=O)OOOC(=O)C=C KCTAWXVAICEBSD-UHFFFAOYSA-N 0.000 description 1
- AABBHSMFGKYLKE-SNAWJCMRSA-N propan-2-yl (e)-but-2-enoate Chemical compound C\C=C\C(=O)OC(C)C AABBHSMFGKYLKE-SNAWJCMRSA-N 0.000 description 1
- 235000019260 propionic acid Nutrition 0.000 description 1
- IUVKMZGDUIUOCP-BTNSXGMBSA-N quinbolone Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H]([C@]4(C=CC(=O)C=C4CC3)C)CC[C@@]21C)C1=CCCC1 IUVKMZGDUIUOCP-BTNSXGMBSA-N 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 239000011163 secondary particle Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 239000004034 viscosity adjusting agent Substances 0.000 description 1
- 235000020234 walnut Nutrition 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
- UHVMMEOXYDMDKI-JKYCWFKZSA-L zinc;1-(5-cyanopyridin-2-yl)-3-[(1s,2s)-2-(6-fluoro-2-hydroxy-3-propanoylphenyl)cyclopropyl]urea;diacetate Chemical compound [Zn+2].CC([O-])=O.CC([O-])=O.CCC(=O)C1=CC=C(F)C([C@H]2[C@H](C2)NC(=O)NC=2N=CC(=CC=2)C#N)=C1O UHVMMEOXYDMDKI-JKYCWFKZSA-L 0.000 description 1
- 229910000166 zirconium phosphate Inorganic materials 0.000 description 1
- LEHFSLREWWMLPU-UHFFFAOYSA-B zirconium(4+);tetraphosphate Chemical compound [Zr+4].[Zr+4].[Zr+4].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LEHFSLREWWMLPU-UHFFFAOYSA-B 0.000 description 1
Images
Abstract
Description
本発明は、自動車エンジン等の内燃機関から排出される排ガスを浄化するために用いられる内燃機関の排ガス浄化装置及びその製造方法、並びに排ガス浄化装置作製用塗料に関する。 The present invention relates to an exhaust gas purification device for an internal combustion engine used for purifying exhaust gas discharged from an internal combustion engine such as an automobile engine, a method for manufacturing the exhaust gas purification device, and a paint for producing the exhaust gas purification device.
自動車ガソリンエンジンより排出される有害物質は、３元触媒により浄化されてきた。
３元触媒は、一般に、高耐熱衝撃性のコーディエライト等よりなるセラミックハニカム構造体を担体として用い、その表面にγ−アルミナ等の高比表面積材料からなる触媒担持層を形成した後、Ｐｔ等の触媒貴金属を担持したものが用いられている。この技術により、ガソリンエンジン車はディーゼルエンジン車と比較してクリーンであるとされてきた。
一方、ディーゼルエンジンも、コモンレールによる燃料噴射制御、ＤＰＦ（ディーゼル・パティキュレート・フィルター）、ＮＯｘ酸化触媒などの排ガス浄化装置により排出ガスはガソリン車並みになってきている。
Hazardous substances emitted from automobile gasoline engines have been purified by a three-way catalyst.
The three-way catalyst generally uses a ceramic honeycomb structure made of cordierite or the like having high thermal shock resistance as a carrier, and after forming a catalyst support layer made of a high specific surface area material such as γ-alumina on the surface, Pt Those carrying catalytic noble metals such as these are used. This technology has made gasoline engine vehicles cleaner than diesel engine vehicles.
On the other hand, diesel engines, the fuel injection control according to the common rail, DPF (diesel particulate filter), the exhaust gas by the exhaust gas purifying device, such as a NO x oxidation catalyst has become gasoline vehicles par.
ところで、近年直径２．５μｍ以下の粒子状物質（ＰＭ：Particulate Matter）が問題となっており、これは燃料種類に関わらず内燃機関の排ガス中に含まれていると言われている。このサイズの粒子は人体の肺に直接取り込まれ、喘息などの健康障害につながるなど指摘されているため、排ガス中に含まれるこれら粒子を取り除く技術開発が望まれている。 By the way, in recent years, particulate matter (PM) with a diameter of 2.5 μm or less has become a problem, and this is said to be contained in the exhaust gas of the internal combustion engine regardless of the type of fuel. Since it has been pointed out that particles of this size are directly taken into the lungs of the human body and lead to health problems such as asthma, it is desired to develop a technology for removing these particles contained in the exhaust gas.
そこで、ディーゼルエンジンではＤＰＦの隔壁表面に微細な気孔径を有するＰＭ捕集層を形成することで、直径２．５μｍ以下を含めたＰＭの捕集と、捕集されたＰＭが堆積した際の圧損を下げるための開発が行われてきた（例えば、特許文献１、２参照）。ここで、ディーゼルエンジンでは排ガス温度が低いことから、捕集・堆積されたＰＭが自己燃焼することが難しい。このため、排ガス中に燃料を供給して強制的に加熱するとともに、ＰＭ捕集層にＰＭ酸化（燃焼）触媒を担持させるなどして、堆積したＰＭを燃焼させて除去する作業が必要とされていた。その作業には燃料が必要となるため、ＰＭ捕集層においてはＰＭ捕集性やＰＭ堆積後の圧損低減だけでなく、燃費を考慮して粒子状物質を堆積しておく必要があった。 Therefore, in a diesel engine, by forming a PM trapping layer having a fine pore diameter on the surface of the partition wall of the DPF, PM trapping including a diameter of 2.5 μm or less, and when the trapped PM is deposited. Developments have been made to reduce pressure loss (see, for example, Patent Documents 1 and 2). Here, since the exhaust gas temperature is low in a diesel engine, it is difficult for the collected and accumulated PM to self-combust. For this reason, it is necessary to supply the fuel into the exhaust gas and forcibly heat it, and to carry the PM collection (combustion) catalyst on the PM trapping layer to burn and remove the accumulated PM. It was. Since the fuel is required for the work, it is necessary to deposit particulate matter in the PM trapping layer in consideration of not only PM trapping property and pressure loss reduction after PM deposition but also fuel efficiency.
一方ガソリンエンジンは、ディーゼルエンジンに比べてＰＭの発生率は非常に低いとされていたことから、ＰＭに対しては特段の対策は取られてなかった。しかしながら、燃費向上を目的とした直噴型ガソリンエンジンでは、従来型のガソリンエンジンに比べてＰＭの発生率が大幅に増加しており、ＰＭ低減対策が必要となってきている（例えば、非特許文献１参照）。 On the other hand, since the gasoline engine was considered to have a much lower PM generation rate than the diesel engine, no special measures were taken against PM. However, direct-injection gasoline engines aimed at improving fuel efficiency have greatly increased the PM generation rate compared to conventional gasoline engines, and measures to reduce PM are required (for example, non-patented) Reference 1).
しかしながら、ディーゼルエンジンにおけるＤＰＦにＰＭ捕集層を設け、さらに酸化触媒を担持させる方法では、構造が複雑となりコストの増加を招くという問題があった。また、触媒担持をウォッシュコートにより行っているため、コート時にＰＭ捕集層の微細な気孔が塞がりやすく、圧損の増加を招くという問題もあった。また、触媒の少なくとも一部はコート層に埋め込まれてしまうために触媒として十分に機能せず、触媒を過剰に担持させる必要があるという問題もあった。 However, the method of providing a PM trapping layer on a DPF in a diesel engine and further supporting an oxidation catalyst has a problem that the structure is complicated and the cost is increased. In addition, since the catalyst is supported by wash coating, the fine pores of the PM trapping layer are likely to be blocked at the time of coating, resulting in an increase in pressure loss. Further, since at least a part of the catalyst is embedded in the coat layer, it does not function sufficiently as a catalyst, and there is a problem that it is necessary to carry the catalyst excessively.
次に、ガソリンエンジンにおけるＰＭ対策としては、ディーゼルエンジンのＤＰＦと同様のＰＭ捕集フィルタの設置が考えられる。ここで、ガソリンエンジンは排ガス温度が通常４００℃を超えることから捕集されたＰＭの自己燃焼が可能であり、ＰＭ捕集フィルタを設置してもディーゼルエンジン車のようなＰＭ堆積はしない。そこで、粒子状物質がフィルタを通過する過程で粒子を確実に燃焼（酸化）させるという特性が求められる。一方、エンジンスタート時などの排気温度が低い際には捕集されたＰＭは燃焼することができないので、排ガス温度が上昇するまでの間、ＰＭを漏らさず堆積させる機能も併せもつ必要がある。
そこで、これら機能を両立するために、従来から３元触媒等に用いられているウォッシュコートなどによる触媒担持と、ＤＰＦで開発されている隔壁表面にコート層を形成することを組み合わせることが考えられるが、そのような構造では明らかに圧損を高めてしまうためガソリン車には不適当であるという問題があった。また、ウォッシュコートを用いて基材上にコート層の形成と触媒担持を行った場合、触媒の少なくとも一部はコート層に埋め込まれてしまうために触媒が十分に機能せず、触媒を過剰に担持させる必要があるという問題もあった。
Next, as a PM countermeasure in a gasoline engine, the installation of a PM collection filter similar to the DPF of a diesel engine can be considered. Here, the gasoline engine is capable of self-combustion of the collected PM because the exhaust gas temperature normally exceeds 400 ° C. Even if a PM collection filter is installed, the PM does not accumulate like a diesel engine vehicle. Therefore, there is a demand for a characteristic that the particles are surely burned (oxidized) in the process of passing the particulate matter through the filter. On the other hand, since the collected PM cannot be combusted when the exhaust gas temperature is low such as when the engine is started, it is necessary to have a function of depositing PM without leaking until the exhaust gas temperature rises.
Therefore, in order to achieve both of these functions, it is conceivable to combine catalyst loading by a wash coat or the like conventionally used for a three-way catalyst and the like, and forming a coat layer on the partition wall surface developed by DPF. However, there is a problem that such a structure is unsuitable for a gasoline vehicle because it obviously increases pressure loss. In addition, when a coat layer is formed on a substrate and a catalyst is supported using a wash coat, the catalyst does not function sufficiently because at least a part of the catalyst is embedded in the coat layer, and the catalyst is excessive. There was also a problem that it was necessary to carry.
本発明は、上記の課題を解決するためになされたものであって、ディーゼルエンジンにおけるＤＰＦの構造簡易化を図るとともに圧損上昇を抑制し、低コストで作製可能な排ガス浄化装置を提供することを目的とする。
また、ガソリンエンジンの排ガス処理のためのＰＭ捕集フィルタを設置した場合においても、フィルタによる圧損上昇を抑制し、また捕集したＰＭを効率良く連続的に酸化処理できるとともに、低コストで作製可能な排ガス浄化装置を提供することを目的とする。より具体的には、４００℃から５００℃程度の排気温度下において、必要最低限の触媒量で高い触媒性能を発揮できる触媒体を実現することにより、効率よく粒子状物質を酸化処理することができ、また圧損が抑制された排ガス浄化装置を提供することを目的とする。
The present invention has been made to solve the above-described problems, and provides an exhaust gas purifying apparatus that can simplify the structure of a DPF in a diesel engine, suppress an increase in pressure loss, and can be manufactured at low cost. Objective.
Moreover, even when a PM collection filter is installed for exhaust gas treatment of a gasoline engine, pressure loss rise due to the filter can be suppressed, and the collected PM can be oxidized continuously and efficiently, and can be manufactured at low cost. An object of the present invention is to provide an exhaust gas purification device. More specifically, it is possible to efficiently oxidize particulate matter by realizing a catalyst body that can exhibit high catalyst performance with a minimum amount of catalyst at an exhaust temperature of about 400 ° C. to 500 ° C. Another object of the present invention is to provide an exhaust gas purifying apparatus capable of suppressing pressure loss.
本発明者等は、上記課題を解決するために鋭意研究を行った結果、セラミックス製の多孔質基材の表面及び気孔内表面に触媒粒子を担持し、この触媒粒子が多孔質基材の表面及び気孔内表面に直接担持されるとともに、その７５％以上が排ガスと直接接する状態で保持されているようにすれば、ディーゼルエンジンにおけるＤＰＦにおいて必ずしもＰＭ捕集層を設けなくて十分なＰＭ除去特性を得ることができ、圧損の抑制を図ることができること、またガソリンエンジンのＰＭ捕集フィルタにおいても触媒量を低減しても高い触媒性能を発揮でき、圧損を抑制することができることを見出し、本発明を完成するに至った。 As a result of intensive studies to solve the above problems, the present inventors have supported catalyst particles on the surface of the porous substrate made of ceramic and the inner surface of the pores, and this catalyst particle is the surface of the porous substrate. In addition, if 75% or more of the fuel is directly supported on the inner surface of the pores and is held in direct contact with the exhaust gas, the PM collection layer is not necessarily provided in the DPF in the diesel engine, and sufficient PM removal characteristics are obtained. It is found that the pressure loss can be suppressed, and the PM collection filter of the gasoline engine can exhibit high catalyst performance even if the catalyst amount is reduced, and the pressure loss can be suppressed. The invention has been completed.
すなわち、本発明の内燃機関の排ガス浄化装置は、セラミックス製の多孔質基材と、前記多孔質基材の表面及び気孔内表面に担持された触媒粒子とを有してなり、前記触媒粒子は、前記多孔質基材の表面及び気孔内表面に直接担持されるとともに、前記触媒粒子の７５％以上が排ガスと直接接する状態で保持されており、前記触媒粒子は、炭化ケイ素粒子の表面に貴金属粒子が担持されてなり、前記貴金属粒子が酸化物層により覆われた状態であることを特徴とする。 That is, the exhaust gas purification apparatus for an internal combustion engine of the present invention comprises a ceramic porous substrate and catalyst particles carried on the surface of the porous substrate and the pore inner surface, and the catalyst particles are And 75% or more of the catalyst particles are held in direct contact with the exhaust gas, and the catalyst particles are supported on the surface of the silicon carbide particles. The particles are supported, and the noble metal particles are covered with an oxide layer.
前記炭化ケイ素粒子の平均一次粒子径は０．００５μｍ以上かつ１μｍ以下であり、前記酸化物層の厚さが２０ｎｍ以下であることが好ましい。
前記多孔質基材における排ガスの流れがウォールフロー型又はフロースルー型であることが好ましい。
The average primary particle diameter of the silicon carbide particles is preferably 0.005 μm or more and 1 μm or less, and the thickness of the oxide layer is preferably 20 nm or less.
The flow of exhaust gas in the porous substrate is preferably a wall flow type or a flow through type.
本発明の内燃機関の排ガス浄化装置の製造方法は、貴金属粒子を炭化ケイ素粒子に担持させ貴金属粒子担持炭化ケイ素粒子を作製する「貴金属粒子担持工程」、前記貴金属粒子担持炭化ケイ素粒子の表面に酸化物層を形成し、前記貴金属粒子が前記酸化物層により覆われた状態で保持された触媒粒子を形成する「触媒粒子形成工程」を含み、さらに、前記貴金属粒子を担持した炭化ケイ素粒子又は触媒粒子を前記多孔質基材の表面及び気孔内表面に保持させる際に造孔材を使用することを特徴とする。 The method for producing an exhaust gas purification apparatus for an internal combustion engine according to the present invention includes a “noble metal particle supporting step” in which noble metal particles are supported on silicon carbide particles to produce noble metal particle-supported silicon carbide particles, and oxidized on the surface of the noble metal particle-supported silicon carbide particles. Including a “catalyst particle forming step” of forming a physical layer and forming catalyst particles in which the noble metal particles are covered with the oxide layer, and further comprising silicon carbide particles or catalysts carrying the noble metal particles A pore former is used when the particles are held on the surface of the porous substrate and the inner surface of the pores.
本発明の内燃機関の排ガス浄化装置を製造するための塗料は、少なくとも、触媒粒子又は触媒粒子前駆体、造孔材、並びに分散媒とを含有してなり、前記塗料が触媒粒子を含む場合、前記触媒粒子の平均分散粒子径が０．１μｍ以上かつ４μｍ以下であり、前記塗料が触媒粒子前駆体を含む場合、前記触媒粒子前駆体に含まれる炭化ケイ素粒子の平均分散粒子径は０．１μｍ以上かつ４μｍ以下であることを特徴とする。 The paint for producing the exhaust gas purification apparatus for an internal combustion engine of the present invention contains at least catalyst particles or a catalyst particle precursor, a pore former, and a dispersion medium, and when the paint contains catalyst particles, When the average dispersed particle size of the catalyst particles is 0.1 μm or more and 4 μm or less, and the paint contains a catalyst particle precursor, the average dispersed particle size of the silicon carbide particles contained in the catalyst particle precursor is 0.1 μm. It is above and 4 micrometers or less, It is characterized by the above-mentioned.
本発明の内燃機関の排ガス浄化装置によれば、セラミックス製の多孔質基材と、前記多孔質基材の表面及び気孔内表面に担持された触媒粒子とを有してなり、前記触媒粒子は、前記多孔質基材の表面及び気孔内表面に直接担持されるとともに、前記触媒粒子の７５％以上が排ガスと直接接する状態で保持されており、前記触媒粒子は、炭化ケイ素粒子の表面に貴金属粒子が担持されてなり、前記貴金属粒子が酸化物層により覆われた状態であることとしたので、多孔質基材に担持された触媒粒子のほとんどが触媒作用を発現することができることから、触媒量を低減しても高い触媒性能を発揮できる。また、触媒粒子担持するためのコート層（触媒担持層）も用いていないことから、圧損を増加させる要因がほとんど無く、従って圧損も抑制することができる。 According to the exhaust gas purifying apparatus for an internal combustion engine of the present invention, it comprises a ceramic porous substrate, and catalyst particles carried on the surface of the porous substrate and the inner surface of the pores. And 75% or more of the catalyst particles are held in direct contact with the exhaust gas, and the catalyst particles are supported on the surface of the silicon carbide particles. Since the particles are supported and the noble metal particles are covered with an oxide layer, most of the catalyst particles supported on the porous substrate can exhibit a catalytic action. Even if the amount is reduced, high catalyst performance can be exhibited. In addition, since no coat layer (catalyst support layer) for supporting catalyst particles is used, there is almost no cause for increasing pressure loss, and therefore pressure loss can be suppressed.
本発明の内燃機関の排ガス浄化装置の製造方法によれば、貴金属粒子を炭化ケイ素粒子に担持させ貴金属粒子担持炭化ケイ素粒子を作製する「貴金属粒子担持工程」、前記貴金属粒子担持炭化ケイ素粒子の表面に酸化物層を形成し、前記貴金属粒子が前記酸化物層により覆われた状態で保持された触媒粒子を形成する「触媒粒子形成工程」を含み、さらに、前記貴金属粒子を担持した炭化ケイ素粒子又は触媒粒子を前記多孔質基材の表面及び気孔内表面に保持させる際に造孔材を使用することとしたので、触媒粒子が多孔質基材の表面及び気孔内表面に直接担持されるとともに、その７５％以上が排ガスと直接接する状態で保持された内燃機関の排ガス浄化装置を得ることができる。よって触媒量を低減しても高い触媒性能を発揮でき、圧損も抑制された内燃機関の排ガス浄化装置を得ることができる。 According to the method for manufacturing an exhaust gas purification apparatus for an internal combustion engine of the present invention, a “noble metal particle supporting step” for producing noble metal particle-supported silicon carbide particles by supporting noble metal particles on silicon carbide particles, the surface of the noble metal particle-supported silicon carbide particles Forming a catalyst layer in which an oxide layer is formed and the noble metal particles are held in a state of being covered with the oxide layer, and further comprising silicon carbide particles carrying the noble metal particles Alternatively, since the pore former is used when the catalyst particles are held on the surface of the porous substrate and the inner surface of the pores, the catalyst particles are directly supported on the surface of the porous substrate and the inner surfaces of the pores. Thus, an exhaust gas purification apparatus for an internal combustion engine in which 75% or more of the internal combustion engine is held in direct contact with the exhaust gas can be obtained. Therefore, it is possible to obtain an exhaust gas purifying apparatus for an internal combustion engine that can exhibit high catalytic performance even when the amount of catalyst is reduced and suppresses pressure loss.
本発明の内燃機関の排ガス浄化装置を製造するための塗料によれば、少なくとも、触媒粒子又は触媒粒子前駆体、造孔材、並びに分散媒とを含有してなり、前記塗料が触媒粒子を含む場合、前記触媒粒子の平均分散粒子径が０．１μｍ以上かつ４μｍ以下であり、前記塗料が触媒粒子前駆体を含む場合、前記触媒粒子前駆体に含まれる炭化ケイ素粒子の平均分散粒子径は０．１μｍ以上かつ４μｍ以下であることとしたので、この塗料を用いることにより、触媒粒子が多孔質基材の表面及び気孔内表面に直接担持されるとともに、前記触媒粒子の７５％以上が排ガスと直接接する状態で保持された内燃機関の排ガス浄化装置を得ることができる。よって触媒量を低減しても高い触媒性能を発揮でき、圧損も抑制された内燃機関の排ガス浄化装置を得ることができる。 According to the paint for producing the exhaust gas purification apparatus for an internal combustion engine of the present invention, at least the catalyst particles or the catalyst particle precursor, the pore former, and the dispersion medium are contained, and the paint contains the catalyst particles. In this case, when the average dispersed particle size of the catalyst particles is 0.1 μm or more and 4 μm or less, and the coating material contains a catalyst particle precursor, the average dispersed particle size of the silicon carbide particles contained in the catalyst particle precursor is 0. By using this paint, the catalyst particles are directly supported on the surface of the porous substrate and the inner surface of the pores, and 75% or more of the catalyst particles are exhausted from the exhaust gas. An exhaust gas purification device for an internal combustion engine held in direct contact can be obtained. Therefore, it is possible to obtain an exhaust gas purifying apparatus for an internal combustion engine that can exhibit high catalytic performance even when the amount of catalyst is reduced and suppresses pressure loss.
本発明の内燃機関の排ガス浄化装置を実施するための形態について説明する。
なお、この形態は、発明の趣旨をより良く理解させるために具体的に説明するものであり、特に指定のない限り、本発明を限定するものではない。
An embodiment for carrying out an exhaust gas purification apparatus for an internal combustion engine according to the present invention will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.
［排ガス浄化装置］
本実施形態の内燃機関の排ガス浄化装置は、セラミックス製の多孔質基材と、前記多孔質基材の表面及び気孔内表面に担持された触媒粒子とを有している。本実施形態の内燃機関の排ガス浄化装置は、排気経路中に触媒を配置するものであって、例えば、ガソリン車、ディーゼル車といった自動車用の排ガス浄化装置として用いられる。
[Exhaust gas purification equipment]
The exhaust gas purifying apparatus for an internal combustion engine of the present embodiment includes a ceramic porous substrate and catalyst particles supported on the surface of the porous substrate and the pore inner surface. The exhaust gas purification apparatus for an internal combustion engine according to the present embodiment arranges a catalyst in an exhaust path, and is used as an exhaust gas purification apparatus for automobiles such as gasoline cars and diesel cars, for example.
セラミックス製の多孔質基材の形態は特に限定されないが、例えば、自動車（ガソリン車、ディーゼル車）の排ガス浄化に用いられるハニカム基材、ディーゼル自動車用のＰＭ捕集除去に用いられるＤＰＦ用フィルタ基材等が代表的なものとして選択できる。この内、ハニカム基材はいわゆるフロースルー型である。このフロースルー型排ガス浄化装置の断面図を図１に示す。 The form of the ceramic porous substrate is not particularly limited. For example, a honeycomb substrate used for exhaust gas purification of automobiles (gasoline vehicles, diesel vehicles), a DPF filter base used for PM collection and removal for diesel vehicles. Materials can be selected as representative. Among these, the honeycomb substrate is a so-called flow-through type. A cross-sectional view of this flow-through type exhaust gas purification apparatus is shown in FIG.
フロースルー型排ガス浄化装置１０は、多孔質基材からなる隔壁１１と、隔壁１１に囲まれ排ガスの流入側と排出側が共に解放されたガス流路１２とを有する。フロースルー型排ガス浄化装置１０は、一方の端面α側から排ガスＧを隔壁１１と並行して流すことにより、隔壁１１を構成する多孔質基材の表面や気孔内の表面に接した排ガスが多孔質基材に担持された触媒（図示略）により浄化される。また、排ガス中のＰＭ３０も多孔質基材の表面や気孔内の表面で捕集され、燃焼除去される。浄化された後の浄化ガスＣは端面γから放出される。
The flow-through type exhaust
一方ＤＰＦ用フィルタ基材はいわゆるウォールフロー型である。このウォールフロー型排ガス浄化装置の断面図を図２に示す。
ウォールフロー型排ガス浄化装置２０は、多孔質基材からなる隔壁２１と、隔壁２１に囲まれたガス流路２２とを有する。ガス流路２２は、ガスの排出側が封止された流入側ガス流路２２Ａと、ガスの流入側が封止された排出側ガス流路２２Ｂとを有する。流入側ガス流路２２Ａと排出側ガス流路２２Ｂとが交互に隣り合って配置されている。そして、端面αから流入側ガス流路２２Ａに入気した排ガスＧが多孔質基材からなる隔壁２１を通過（透過）して排出側ガス流路２２Ｂへと放出される際に、多孔質基材の表面や気孔内の表面に接した排ガスＧが多孔質基材に担持された触媒により浄化されるものである。また、排ガス中のＰＭ３０も、隔壁２１を通過するときに多孔質基材の表面や気孔内の表面で捕集され、燃焼除去される。浄化された後の浄化ガスＣは端面γから放出される。
そして、本実施形態の内燃機関の排気浄化装置は、フロースルー型、ウォールフロー型のいずれを用いることも可能である。
On the other hand, the filter substrate for DPF is a so-called wall flow type. A cross-sectional view of this wall flow type exhaust gas purification apparatus is shown in FIG.
The wall flow type exhaust
The exhaust gas purification apparatus for an internal combustion engine according to the present embodiment can use either a flow-through type or a wall flow type.
多孔質基材に用いられるセラミックの材質は、耐熱性を有するものであれば特に限定されず、例えば、コーディエライト、アルミナ、スピネル、ムライト、チタン酸アルミニウム、リン酸ジルコニウム、窒化ケイ素、炭化ケイ素、ゼオライト、ペロブスカイト及びシリカ−アルミナ等を主成分として含むものを用いることができる。
特に自動車排気浄化装置の場合には、高温条件で使用されることから、耐熱性に優れる炭化ケイ素を主成分とするものを好適に用いることができる。また、後述するように、本実施形態の触媒粒子は炭化ケイ素粒子の表面に貴金属粒子が担持された貴金属担持炭化ケイ素粒子であることから、多孔質基材として炭化ケイ素を主成分とするものを用いれば触媒粒子との親和性も良く好ましい。
The ceramic material used for the porous substrate is not particularly limited as long as it has heat resistance. For example, cordierite, alumina, spinel, mullite, aluminum titanate, zirconium phosphate, silicon nitride, silicon carbide , Zeolite, perovskite, silica-alumina and the like as main components can be used.
In particular, in the case of an automobile exhaust purification device, since it is used under high temperature conditions, it is possible to suitably use a material mainly composed of silicon carbide having excellent heat resistance. Further, as will be described later, since the catalyst particles of the present embodiment are noble metal-supported silicon carbide particles in which noble metal particles are supported on the surface of the silicon carbide particles, those having silicon carbide as a main component as a porous substrate. If used, the affinity with the catalyst particles is good and preferable.
フロースルー型の場合、多孔質基材からなる隔壁の厚さは２００μｍ〜５００μｍ程度が好ましい。その理由として、一般的なガソリンエンジン用排ガス浄化装置に用いられるフロースルー型ハニカム基材では、排ガスが隔壁内に入り込む深さは２５０μｍ程度であることが挙げられる。すなわち、排ガス中のＰＭの捕集・燃焼やその他成分の浄化処理とも隔壁の表面又は表面から２５０μｍ程度までの深さで行われることから、隔壁の厚さが５００μｍよりも厚い場合、排ガスが流れ込まず排ガス処理に寄与しない部分が生じるためである。一方、隔壁の厚さが２００μｍより薄くなると、ハニカム基材としての強度が不足し、熱履歴等で破損を生じる虞がある。 In the case of the flow-through type, the thickness of the partition wall made of a porous substrate is preferably about 200 μm to 500 μm. The reason for this is that in a flow-through type honeycomb substrate used in a general exhaust gas purification device for a gasoline engine, the depth at which the exhaust gas enters the partition walls is about 250 μm. That is, the collection and combustion of PM in the exhaust gas and the purification process of other components are performed at the surface of the partition wall or at a depth of about 250 μm from the surface. Therefore, when the partition wall thickness is thicker than 500 μm, the exhaust gas flows. This is because there is a portion that does not contribute to the exhaust gas treatment. On the other hand, if the partition wall thickness is thinner than 200 μm, the strength as a honeycomb substrate is insufficient, and there is a risk of causing damage due to thermal history or the like.
また、本実施形態の内燃機関の排ガス浄化装置では、触媒粒子は、上記多孔質基材の表面及び気孔内表面に直接担持されるとともに、上記触媒粒子の７５％以上が排ガスと直接接する状態で保持されていることが特徴としている。従って、フロースルー型の場合における触媒粒子は、隔壁の表面及び表面から２５０μｍ程度までの深さの気孔の表面に担時されていることが好ましい。隔壁の表面から２５０μｍ以上の深さの気孔内表面に触媒を担持させても、その部分には排ガスが流入しないため、担持させる意味が無いためである。
なお、触媒粒子は、その８０％以上が排ガスと直接接する状態で保持されていることが好ましく、９０％以上が排ガスと直接接する状態で保持されていればより好ましい。
In the exhaust gas purification apparatus for an internal combustion engine of the present embodiment, the catalyst particles are directly supported on the surface of the porous base material and the inner surface of the pores, and 75% or more of the catalyst particles are in direct contact with the exhaust gas. It is characterized by being retained. Therefore, it is preferable that the catalyst particles in the case of the flow-through type are carried on the surface of the partition walls and the surface of the pores having a depth of about 250 μm from the surface. This is because even if the catalyst is supported on the inner surface of the pores having a depth of 250 μm or more from the surface of the partition wall, the exhaust gas does not flow into that portion, so there is no point in supporting it.
Note that 80% or more of the catalyst particles are preferably held in direct contact with the exhaust gas, and more preferably 90% or more of the catalyst particles are held in direct contact with the exhaust gas.
この触媒粒子担時の観点からも、フロースルー型の隔壁の厚さは５００μｍ以下であることが好ましい。すなわち、隔壁の厚さが５００μｍより薄ければ、隔壁の表面及び隔壁内部の気孔の表面全体に触媒粒子を担持できるから、触媒担時に特定の方法を用いたり、隔壁に特定の構造を形成させたりする必要が無い。一方、隔壁が５００μｍより厚い場合には、例えば触媒粒子の担時前に深部の気孔を塞いでおくことや、隔壁自体の構造を表面側の気孔率が高いものとしておく必要が生じる。
なお、隔壁への排ガスの流入量は厚さとともに減少するから、隔壁が５００μｍより薄い場合であっても、触媒粒子の担時量は隔壁表面が最も多いことが好ましくまた、内部においてはより表面に近い気孔の表面への担時量が多いことが好ましい。
From the viewpoint of supporting the catalyst particles, the thickness of the flow-through partition is preferably 500 μm or less. That is, if the partition wall thickness is less than 500 μm, the catalyst particles can be supported on the entire surface of the partition wall and the pores inside the partition wall. Therefore, a specific method is used when the catalyst is supported, or a specific structure is formed on the partition wall. There is no need to On the other hand, when the partition wall is thicker than 500 μm, for example, it is necessary to close the pores in the deep part before carrying the catalyst particles, or to make the structure of the partition wall itself have a high porosity on the surface side.
In addition, since the amount of exhaust gas flowing into the partition wall decreases with the thickness, even when the partition wall is thinner than 500 μm, the amount of catalyst particles supported is preferably the largest on the partition wall surface, and more inside It is preferable that the amount of loading on the surface of pores close to is large.
次にウォールフロー型の場合、多孔質基材からなる隔壁の厚さは、２００μｍ〜３００μｍ程度が好ましい。ウォールフロー型では、隔壁の厚さが排気抵抗と直接関係するため、隔壁の厚さが３００μｍを超えると圧損が増大する虞がある。一方、隔壁の厚さが２００μｍより薄いと、ＰＭの捕集性が低下するほか、やはりフィルタ基材としての強度が不足し、熱履歴等で破損を生じる虞がある。 Next, in the case of the wall flow type, the thickness of the partition wall made of a porous substrate is preferably about 200 μm to 300 μm. In the wall flow type, since the partition wall thickness is directly related to the exhaust resistance, the pressure loss may increase when the partition wall thickness exceeds 300 μm. On the other hand, if the partition wall thickness is less than 200 μm, the PM trapping property is lowered, and the strength as a filter base material is also insufficient, which may cause damage due to heat history or the like.
ここでウォールフロー型の場合、排ガスは隔壁内部を通過するから、触媒粒子は流入側ガス流路の隔壁表面及び隔壁内部の気孔表面の全体にわたって担持されていて良い。また、排出側ガス流路の隔壁表面に担持されていてもよい。ただし、流入側ガス流路隔壁表面への担時が無いかごく少なく、一方排出側ガス流路隔壁表面へに担時量が多い場合には、排ガスの処理が十分行えなくなる虞があるため好ましくない。 Here, in the case of the wall flow type, since the exhaust gas passes through the inside of the partition wall, the catalyst particles may be supported over the entire partition wall surface of the inflow side gas flow channel and the pore surface inside the partition wall. Moreover, you may carry | support on the partition wall surface of a discharge side gas flow path. However, if there is very little time on the inflow side gas flow path partition surface, while there is a large amount on the exhaust side gas flow path partition surface, the exhaust gas treatment may not be sufficiently performed, which is preferable. Absent.
また多孔質基材からなる隔壁の平均気孔径は、フロースルー型、ウォールフロー型とも１０μｍ以上かつ５０μｍ以下であることが好ましい。平均気孔径が１０μｍより小さい場合には、隔壁内における排ガス流に対する抵抗が大きくなるため、フロースルー型では排ガス浄化作用が低下する虞があり、ウォールフロー型では圧損が増加する虞があり好ましくない。一方、平均気孔径が５０μｍを超える場合には、隔壁内流れ込んだ排ガスの内気孔表面と接触する排ガス量が減少するために、フロースルー型、ウォールフロー型とも排ガス浄化作用が低下する虞があり好ましくない。 The average pore diameter of the partition wall made of a porous substrate is preferably 10 μm or more and 50 μm or less for both the flow-through type and the wall flow type. When the average pore diameter is smaller than 10 μm, the resistance to the exhaust gas flow in the partition wall increases, so that the exhaust gas purification action may decrease in the flow-through type, and the pressure loss may increase in the wall flow type, which is not preferable. . On the other hand, when the average pore diameter exceeds 50 μm, the amount of exhaust gas coming into contact with the inner pore surface of the exhaust gas flowing into the partition wall decreases, so there is a possibility that the exhaust gas purification action of both the flow-through type and wall flow type may be reduced. It is not preferable.
以上示したような、厚さが２００μｍ〜３００μｍ程度、平均気孔径が１０μｍ〜５０μｍの隔壁を有する多孔質基材としては、自動車（ガソリン車、ディーゼル車）用排ガス浄化装置に用いられる通常のハニカム基材やディーゼル自動車用のＰＭ捕集除去に用いられるＤＰＦ用フィルタ基材を用いることができる。
一方、多孔質基材は触媒粒子を直接担持することから、その表面や気孔内の表面に触媒粒子を直接担持可能な細孔を有していればより好ましい。本実施形態においては、触媒粒子を形成する炭化ケイ素粒子の平均一次粒子径を０．００５μｍ以上かつ１μｍ以下としていることから、触媒粒子を直接担持可能な細孔の直径は３ｎｍから２μｍ程度が好ましい。また、細孔の深さは２ｎｍから８００ｎｍ程度で良いが、触媒粒子が細孔内に完全に入り込まない程度の深さが好ましい。また、細孔の数は１×１０１１個／Ｌ以上が好ましく、１×１０１６個／Ｌ以上であればより好ましい。
As a porous substrate having a partition wall having a thickness of about 200 μm to 300 μm and an average pore diameter of 10 μm to 50 μm as described above, a normal honeycomb used for an exhaust gas purification apparatus for automobiles (gasoline cars, diesel cars) is used. The filter base material for DPF used for the base material and PM collection and removal for diesel vehicles can be used.
On the other hand, since the porous substrate directly supports the catalyst particles, it is more preferable that the porous substrate has pores capable of directly supporting the catalyst particles on the surface or the surface in the pores. In this embodiment, since the average primary particle diameter of the silicon carbide particles forming the catalyst particles is 0.005 μm or more and 1 μm or less, the diameter of the pores capable of directly supporting the catalyst particles is preferably about 3 nm to 2 μm. . Further, the depth of the pores may be about 2 nm to 800 nm, but a depth that does not allow the catalyst particles to completely enter the pores is preferable. The number of pores is preferably 1 × 10 11 / L or more, and more preferably 1 × 10 16 / L or more.
本実施形態の内燃機関の排ガス浄化装置では、以上のような多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に、触媒粒子を直接担持させる。担持させる触媒粒子は、炭化ケイ素粒子の表面に貴金属粒子が担持されてなり、該貴金属粒子が、炭化ケイ素粒子の表面に形成された酸化物層により覆われた状態である粒子が選択される。 In the exhaust gas purifying apparatus for an internal combustion engine of the present embodiment, catalyst particles are directly supported on the surface of the partition wall made of the porous substrate as described above and the surface of the pores inside the partition wall. The catalyst particles to be supported are selected from particles in which noble metal particles are supported on the surface of silicon carbide particles, and the noble metal particles are covered with an oxide layer formed on the surface of the silicon carbide particles.
炭化ケイ素粒子としては、平均一次粒子径が０．００５μｍ以上かつ１μｍ以下であることが好ましい。
ここで、炭化ケイ素粒子の平均一次粒子径が０．００５μｍ未満では、この炭化ケイ素粒子の表面活性が高くなり過ぎてしまい、この触媒粒子を用いた排ガス浄化装置を高温下で使用した際に、触媒粒子が多孔質基材と反応してしまい、触媒活性が低下する結果、排ガス浄化機能が低下する虞があるため好ましくない。一方、平均一次粒子径が１μｍを越えると、特に触媒粒子を多孔質基材に担持する際に触媒粒子の平均分散粒子径が大きくなりすぎてしまうために、多孔質基材の気孔内に触媒粒子が入り込めなくなり、やはり排ガス浄化装置において十分な浄化機能が得られなくなる虞があり好ましくない。
なお炭化ケイ素粒子の平均一次粒子径は０．０２μｍ以上かつ０．８５μｍ以下がより好ましく、０．０３５μｍ以上かつ０．６μｍ以下であればさらに好ましい。
The silicon carbide particles preferably have an average primary particle size of 0.005 μm or more and 1 μm or less.
Here, when the average primary particle diameter of the silicon carbide particles is less than 0.005 μm, the surface activity of the silicon carbide particles becomes too high, and when the exhaust gas purification apparatus using the catalyst particles is used at a high temperature, Since the catalyst particles react with the porous substrate and the catalytic activity is lowered, the exhaust gas purification function may be lowered. On the other hand, if the average primary particle diameter exceeds 1 μm, the average dispersed particle diameter of the catalyst particles becomes too large particularly when the catalyst particles are supported on the porous substrate. It is not preferable because the particles cannot enter and there is a possibility that a sufficient purification function cannot be obtained in the exhaust gas purification apparatus.
The average primary particle diameter of the silicon carbide particles is more preferably 0.02 μm to 0.85 μm, and even more preferably 0.035 μm to 0.6 μm.
貴金属粒子としては、白金（Ｐｔ）、金（Ａｕ）、銀（Ａｇ）、ルテニウム（Ｒｕ）、ロジウム（Ｒｈ）、パラジウム（Ｐｄ）、オスミウム（Ｏｓ）、イリジウム（Ｉｒ）の群から選択される１種又は２種以上を含有していることが好ましく、浄化対象とする物質（炭化水素系有機物：ＨＣ、一酸化炭素：ＣＯ、窒素酸化物：ＮＯｘ、粒子状物質：ＰＭ）を考慮した上で選択することが好ましい。例えば、ＰＭ燃焼等の酸化触媒作用を有する貴金属としては、白金、パラジウム、ロジウム等から選択される１種ないし２種以上を用いることができる。また、ＮＯｘ還元触媒としてはパラジウム、イリジウム等やこれら貴金属粒子と各種の化合物粒子を組み合わせて用いることができる。この貴金属粒子の一次粒子径は１ｎｍ以上かつ３０ｎｍ以下が好ましく、１ｎｍ以上かつ２０ｎｍ以下がより好ましく、１ｎｍ以上かつ１０ｎｍ以下であればさらに好ましい。そして、この貴金属粒子は、炭化ケイ素粒子表面に形成された酸化物層により覆われている。 The noble metal particles are selected from the group consisting of platinum (Pt), gold (Au), silver (Ag), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), and iridium (Ir). It is preferable to contain 1 type or 2 types or more, considering the substances to be purified (hydrocarbon organic matter: HC, carbon monoxide: CO, nitrogen oxide: NO x , particulate matter: PM) Preferably selected above. For example, as the noble metal having an oxidation catalytic action such as PM combustion, one or more selected from platinum, palladium, rhodium, and the like can be used. In addition, as the NO x reduction catalyst, palladium, iridium or the like, or a combination of these noble metal particles and various compound particles can be used. The primary particle size of the noble metal particles is preferably 1 nm to 30 nm, more preferably 1 nm to 20 nm, and even more preferably 1 nm to 10 nm. The noble metal particles are covered with an oxide layer formed on the surface of the silicon carbide particles.
ここで、貴金属粒子の平均一次粒子径が１ｎｍ未満では、粒子径が小さすぎて表面活性が強くなりすぎてしまい、凝集し易くなるので好ましくない。一方、平均一次粒径が３０ｎｍを超えると、貴金属粒子が炭化ケイ素粒子表面の酸化物層により覆いきれなくなり、酸化物層から突出して露出するようになるために、特に高温化で貴金属粒子がシンタリング（粒子成長）を起こすために触媒特性が低下する虞があり好ましくない。 Here, if the average primary particle diameter of the noble metal particles is less than 1 nm, the particle diameter is too small, the surface activity becomes too strong, and aggregation is likely to occur, which is not preferable. On the other hand, when the average primary particle size exceeds 30 nm, the noble metal particles cannot be covered with the oxide layer on the surface of the silicon carbide particles and are exposed to protrude from the oxide layer. Since the ring (particle growth) is caused, the catalyst characteristics may be deteriorated, which is not preferable.
ここで、この炭化ケイ素粒子の表面には酸化物層が形成されている。酸化物層の厚さは２０ｎｍ以下が好ましい。酸化物層の厚さは、後述の貴金属粒子を完全に覆うという観点からは厚い方が良いが、一方、酸化物層が厚すぎると貴金属粒子による触媒効果を減じてしまうことから、２０ｎｍ以下の厚さが選択される。 Here, an oxide layer is formed on the surface of the silicon carbide particles. The thickness of the oxide layer is preferably 20 nm or less. The thickness of the oxide layer is preferably thick from the viewpoint of completely covering the noble metal particles to be described later. On the other hand, if the oxide layer is too thick, the catalytic effect by the noble metal particles is reduced. The thickness is selected.
また、この酸化物層は、非晶質のＳｉＯｘＣｙ（ただし、０＜ｘ≦３、０≦ｙ≦３）を含有してなることが好ましい。なお、この酸化物層の組成や構造は単一である必要はなく、酸化物層の各部分におけるｘ及びｙの値は上記の範囲内で任意の値を取ることができる。さらに、この酸化物層は、ＳｉＯ２、ＳｉＯ、ＳｉＯＣ３、ＳｉＯ２Ｃ２及びＳｉＯ３Ｃの群から選択される１種又は２種以上の結晶質を含有していてもよい。 The oxide layer preferably contains amorphous SiO x C y (where 0 <x ≦ 3, 0 ≦ y ≦ 3). Note that the composition and structure of the oxide layer do not have to be single, and the values of x and y in each part of the oxide layer can take arbitrary values within the above range. Further, the oxide layer may contain one or more crystalline materials selected from the group consisting of SiO 2 , SiO, SiOC 3 , SiO 2 C 2 and SiO 3 C.
また、この酸化物層は、酸素を吸着し、酸化物層に接触した物質に吸着した酸素を付与する作用、すなわち酸化触媒作用を有している。従って、貴金属粒子として酸化触媒作用を有する粒子を選択した場合には、酸化物層により、該貴金属粒子の有する酸化触媒能を増強する効果が得られる。これにより、排ガス中に含まれるＰＭの燃焼温度を低下させることができるので、排ガス浄化装置の熱負荷を低減できるとともに、連続再生も容易に行うことが可能となる。すなわち、酸化物層は、前記のように貴金属粒子を覆うことで、貴金属粒子のシンタリング防止をはかるだけでなく、排ガス浄化装置の特性向上も図ることができる。 The oxide layer has an action of adsorbing oxygen and imparting the adsorbed oxygen to a substance in contact with the oxide layer, that is, an oxidation catalytic action. Therefore, when particles having an oxidation catalytic action are selected as the noble metal particles, the oxide layer can enhance the oxidation catalyst ability of the noble metal particles. Thereby, since the combustion temperature of PM contained in the exhaust gas can be lowered, the heat load of the exhaust gas purification device can be reduced, and continuous regeneration can be easily performed. That is, by covering the noble metal particles as described above, the oxide layer can not only prevent sintering of the noble metal particles but also improve the characteristics of the exhaust gas purification device.
また、本実施形態の触媒粒子は、主要な触媒成分となる貴金属粒子が炭化ケイ素粒子に担持されており、さらに炭化ケイ素粒子の表面には酸化物層が形成されている。この炭化ケイ素粒子と酸化物層が存在することにより、本実施形態の触媒粒子は多孔質基材の表面や気孔内表面に直接かつ容易に担持できる。すなわち、多孔質基材が酸化物系セラミックス製の場合には、触媒粒子表面の酸化物層が多孔質基材に対して結合性を有しており、また多孔質基材が非酸化物系セラミックス製の場合には、炭化ケイ素粒子自体が多孔質基材に親和性を有する他、触媒粒子表面の酸化物層が焼結所剤としての効果を発揮することで、多孔質基材と触媒粒子との結合性を向上させる。 Further, in the catalyst particles of the present embodiment, noble metal particles as main catalyst components are supported on silicon carbide particles, and an oxide layer is formed on the surface of the silicon carbide particles. Due to the presence of the silicon carbide particles and the oxide layer, the catalyst particles of the present embodiment can be directly and easily supported on the surface of the porous substrate or the inner surface of the pores. That is, when the porous substrate is made of an oxide ceramic, the oxide layer on the surface of the catalyst particles has a binding property to the porous substrate, and the porous substrate is a non-oxide type. In the case of ceramics, the silicon carbide particles themselves have an affinity for the porous substrate, and the oxide layer on the surface of the catalyst particles exhibits an effect as a sintering agent, so that the porous substrate and the catalyst Improves bondability with particles.
ここで、従来の排ガス浄化装置においては、多孔質基材に貴金属触媒粒子を担持させるためにγ−アルミナ等の高比表面積のコート層を用いている。すなわち、多孔質基材の表面及び気孔内の表面に予めコート層を形成した後に、貴金属触媒粒子を担持している。
これに対して、本実施形態の排ガス浄化装置ではコート層を形成する必要が無いことから、工程の簡易化を行うことができる。また、触媒粒子の担持がコート層の形成状態に左右されないので、目的とする触媒粒子の担持状態を、容易にかつ再現性良く得ることができる。
Here, in the conventional exhaust gas purification apparatus, a coating layer having a high specific surface area such as γ-alumina is used in order to support the noble metal catalyst particles on the porous substrate. That is, the noble metal catalyst particles are supported after a coating layer is formed in advance on the surface of the porous substrate and the surface in the pores.
On the other hand, since it is not necessary to form a coat layer in the exhaust gas purification apparatus of the present embodiment, the process can be simplified. Further, since the support of the catalyst particles is not affected by the formation state of the coat layer, the target support state of the catalyst particles can be obtained easily and with good reproducibility.
また、コート層の形成を省略するために、貴金属触媒粒子とコート層形成粒子とを予め混合して多孔質基材に担持させる方法もある。しかしながら、この方法では一部の貴金属触媒粒子はコート層中に埋め込まれてしまうために触媒機能が発現せず、結果として、本来必要とされる以上の貴金属触媒粒子が必要となり、コストアップを招いてしまう。また、触媒金属粒子同士がコート層中で近接しているために、特に高温化で貴金属粒子がシンタリングを起こし、触媒活性が低下する虞がある。
これに対して、本実施形態の排ガス浄化装置ではコート層自体が無いことから、触媒粒子がコート層中に埋没することはなく、ほとんどの触媒粒子が排ガスに接することができる。
In order to omit the formation of the coat layer, there is a method in which the noble metal catalyst particles and the coat layer forming particles are mixed in advance and supported on the porous substrate. However, in this method, some noble metal catalyst particles are embedded in the coating layer, so that the catalytic function does not appear. As a result, more noble metal catalyst particles than necessary are required, resulting in an increase in cost. I will. Further, since the catalyst metal particles are close to each other in the coat layer, the noble metal particles are sintered particularly at a high temperature, and the catalytic activity may be lowered.
In contrast, since the exhaust gas purifying apparatus of the present embodiment does not have a coat layer itself, the catalyst particles are not buried in the coat layer, and most of the catalyst particles can come into contact with the exhaust gas.
これらの効果により、本実施形態の排ガス浄化装置では、触媒粒子の７５％以上が排ガスと直接接する状態で保持することができる。これにより、多孔質基材に担持された触媒粒子のほとんどが触媒作用を発現することができることから、触媒量を低減しても高い触媒性能を発揮することができる。
さらに、コート層が無いことから、基材セラミックの特性変化を生じることが無く、またコート層による気孔径の減少も生じないことから、圧損を上昇させる要因が無くなり圧損を抑制することができる。
さらにまた、触媒粒子上の貴金属粒子は酸化物層により覆われて固定されていることから、貴金属粒子のシンタリングも生じないので、触媒活性が低下することもない。
なお、触媒粒子は、その８０％以上が排ガスと直接接する状態で保持されていることが好ましく、９０％以上が排ガスと直接接する状態で保持されていればより好ましい。
Due to these effects, in the exhaust gas purifying apparatus of the present embodiment, 75% or more of the catalyst particles can be held in direct contact with the exhaust gas. Thereby, since most of the catalyst particles carried on the porous substrate can exhibit a catalytic action, high catalytic performance can be exhibited even if the amount of catalyst is reduced.
Furthermore, since there is no coating layer, the characteristics of the base ceramic are not changed, and the pore diameter is not reduced by the coating layer, so that there is no cause for increasing the pressure loss and the pressure loss can be suppressed.
Furthermore, since the noble metal particles on the catalyst particles are covered and fixed by the oxide layer, sintering of the noble metal particles does not occur, so that the catalytic activity does not decrease.
Note that 80% or more of the catalyst particles are preferably held in direct contact with the exhaust gas, and more preferably 90% or more of the catalyst particles are held in direct contact with the exhaust gas.
本実施形態における内燃機関の排ガス浄化装置に流入した排ガスは、多孔質基材からなる隔壁に接触又は通過する。そして、排ガスが多孔質基材からなる隔壁の表面及び気孔を通過する段階で、排ガス中に含まれるＰＭが隔壁の表面又は隔壁内部の気孔の表面に捕集される。捕集されたＰＭは、隔壁の表面や隔壁内部の気孔の表面に触媒粒子が担持されていること、また、特にガソリンエンジンの場合には排気温度が高いことから、捕集後速やかに酸化されてＣＯ２となり除去される。 The exhaust gas that has flowed into the exhaust gas purification apparatus for an internal combustion engine in the present embodiment contacts or passes through a partition wall made of a porous substrate. Then, at the stage where the exhaust gas passes through the surface and pores of the partition wall made of the porous substrate, PM contained in the exhaust gas is collected on the surface of the partition wall or the surface of the pores inside the partition wall. The collected PM is oxidized quickly after collection because catalyst particles are supported on the surface of the partition walls and the pores inside the partition walls, and especially in the case of gasoline engines, the exhaust temperature is high. To be removed as CO 2 .
また、この排ガス中にはＣＯ、ＨＣ、ＮＯｘ等も含まれるが、多孔質基材からなる隔壁中を排ガスが流れる過程で、これらの物質も触媒粒子と接触する。そこで、ＰＭの捕集と酸化除去と併せて、３元触媒と同様の作用を行わせることにより、ＣＯをＣＯ２に、ＨＣをＨ２ＯとＣＯ２にそれぞれ酸化・分解させるとともに、ＮＯｘをＮ２に還元させることができる。
以上により、本実施形態における内燃機関の排ガス浄化装置から大気中に排出される排ガスは、基本的にＣＯ２、Ｈ２Ｏ、Ｎ２のみとなり、排ガス中に含まれる有害成分（ＣＯ、ＨＣ、ＮＯｘ等）や粒子状物質（ＰＭ）の無害化処理を連続処理として行うことができる。
The exhaust gas also contains CO, HC, NO x, etc., but these substances also come into contact with the catalyst particles in the process of flowing the exhaust gas through the partition wall made of the porous substrate. Therefore, in conjunction with the collection and oxidation removal of PM, by causing the same effect as 3-way catalyst, the CO to CO 2, together with the oxidation-decomposing each of HC H 2 O and CO 2, NO x Can be reduced to N 2 .
As described above, the exhaust gas discharged into the atmosphere from the exhaust gas purifying apparatus of the internal combustion engine in the present embodiment is basically only CO 2 , H 2 O, N 2, and harmful components (CO, HC, NO x etc.) and particulate matter (PM) detoxification treatment can be performed as a continuous treatment.
［排ガス浄化装置の製造方法］
本実施形態の内燃機関の排ガス浄化装置の製造方法について説明する。
本発明の内燃機関の排ガス浄化装置の製造方法では、貴金属粒子を炭化ケイ素粒子に担持させ貴金属粒子担持炭化ケイ素粒子を作製する「貴金属粒子担持工程」、前記貴金属粒子担持炭化ケイ素粒子の表面に酸化物層を形成し、前記貴金属粒子が前記酸化物層により覆われた状態で保持された触媒粒子を形成する「触媒粒子形成工程」を含み、さらに、前記貴金属粒子を担持した炭化ケイ素粒子又は触媒粒子を前記多孔質基材の表面及び気孔内表面に保持させる際に造孔材を使用する。
[Manufacturing method of exhaust gas purification device]
A method for manufacturing an exhaust gas purification apparatus for an internal combustion engine according to the present embodiment will be described.
In the method for manufacturing an exhaust gas purification apparatus for an internal combustion engine of the present invention, a “noble metal particle supporting step” in which noble metal particles are supported on silicon carbide particles to produce noble metal particle-supported silicon carbide particles, and oxidized on the surface of the noble metal particle-supported silicon carbide particles. Including a “catalyst particle forming step” of forming a physical layer and forming catalyst particles in which the noble metal particles are covered with the oxide layer, and further comprising silicon carbide particles or catalysts carrying the noble metal particles A pore former is used when the particles are held on the surface of the porous substrate and the inner surface of the pores.
また、本発明の内燃機関の排ガス浄化装置の製造方法では、前記の「貴金属粒子担持工程」及び「触媒粒子形成工程」以外にも、各種の工程を必要とする。そこで、以下に典型的な工程順を仮定した上で、その各工程を説明する。 In addition, in the method for manufacturing an exhaust gas purification apparatus for an internal combustion engine according to the present invention, various processes are required in addition to the “precious metal particle supporting process” and the “catalyst particle forming process”. Therefore, each process will be described below assuming a typical process order.
典型的な工程は、次の通りである。
１）炭化ケイ素粒子に貴金属粒子を担持させ貴金属粒子担持炭化ケイ素粒子を作製する「貴金属粒子担持工程」。
２）貴金属粒子担持炭化ケイ素粒子の表面に酸化膜を形成して触媒粒子とする「触媒粒子形成工程」。
３）触媒粒子と造孔材とを含有する塗料を作製する「塗料作製工程」。
４）多孔質基材を塗料で処理することにより、多孔質基材の表面及び気孔内表面に触媒粒子と造孔材とを付着させる「多孔質基材への粒子保持工程」。
５）触媒粒子と造孔材とが付着した多孔質基材から造孔材を除去して、貴金属粒子担持炭化ケイ素粒子のみが保持された多孔質基材とする「造孔材除去工程」。
６）触媒粒子のみが保持された多孔質基材の前記触媒粒子を、前記多孔質基材の表面及び気孔内表面に固定して担持させる「担持工程」。
A typical process is as follows.
1) “Noble metal particle supporting step” in which noble metal particles are supported on silicon carbide particles to produce noble metal particle supported silicon carbide particles.
2) “Catalyst particle forming step” in which an oxide film is formed on the surface of noble metal particle-supporting silicon carbide particles to form catalyst particles.
3) “Paint preparation process” for preparing a paint containing catalyst particles and a pore former.
4) “Particle retention step on the porous substrate” in which the catalyst particles and the pore former are adhered to the surface of the porous substrate and the inner surface of the pores by treating the porous substrate with a paint.
5) “Pore-forming material removing step” in which the pore-forming material is removed from the porous base material to which the catalyst particles and the pore-forming material are adhered, and only the noble metal particle-supporting silicon carbide particles are retained.
6) “Supporting step” in which the catalyst particles of the porous substrate on which only the catalyst particles are held are fixedly supported on the surface of the porous substrate and the pore inner surface.
これらの工程については、可能な範囲でその順番を入れ替えてもよく、また複数の工程を並行又は連続的に行ったり、１つの工程をさらに分割して他の工程と組み合わせてもよい。 About these processes, the order may be changed in the possible range, a plurality of processes may be performed in parallel or continuously, or one process may be further divided and combined with other processes.
例えば、「造孔材除去工程」及び「担持工程」は通常加熱処理によることから、加熱温度や雰囲気を調整しつつ、これらの工程を連続的に行うことができる。また、炭化ケイ素粒子、貴金属粒子及び造孔材を含む塗料を作成し、この塗料を用いて多孔質基材を処理することにより、「貴金属粒子担持工程」と「多孔質基材への粒子保持工程」を同時に行うこともできる。さらには、「塗料作製工程」において、触媒粒子の代わりに触媒粒子前駆体を用い、当該塗料を用いて多孔質基材への粒子保持及び造孔材除去を行って後、多孔質基材上で触媒粒子を形成することもできる。
「触媒粒子前駆体」については、後述する。
For example, since the “pore forming material removing step” and the “supporting step” are usually performed by heat treatment, these steps can be performed continuously while adjusting the heating temperature and atmosphere. In addition, by creating a paint containing silicon carbide particles, noble metal particles and a pore former, and treating the porous substrate with this paint, the "noble metal particle loading process" and "particle retention on the porous substrate" The “step” can be performed simultaneously. Furthermore, in the “paint preparation step”, a catalyst particle precursor is used in place of the catalyst particles, and the paint is used to retain particles on the porous substrate and remove the pore former, and then the porous substrate. Catalyst particles can also be formed.
The “catalyst particle precursor” will be described later.
一方、後述のように、「貴金属粒子担持工程」と「触媒粒子形成工程」は連続して行うことが好ましい。また、「塗料作製工程」から「担持工程」までの４工程については、その内容上、各工程の順番が入れ替ることはない。 On the other hand, as will be described later, it is preferable to perform the “noble metal particle supporting step” and the “catalyst particle forming step” continuously. Further, regarding the four steps from the “paint preparation step” to the “supporting step”, the order of each step is not interchanged due to its contents.
「貴金属粒子担持工程」
触媒粒子の母材となる炭化ケイ素粒子を準備し、この炭化ケイ素粒子の表面に貴金属粒子を担持して、貴金属担持炭化ケイ素粒子を形成する工程である。
炭化ケイ素粒子の平均一次粒子径は、要求される排ガス浄化触媒及び排ガス浄化装置の特性に合わせて０．００５μｍ以上かつ１μｍ以下の範囲で選定する。また、後述の塗料の項で示すような比表面積を有することが好ましい。この炭化ケイ素粒子は、既述の方法、すなわちナノメートルサイズの粒子であれば、熱プラズマ法やシリカ前駆体焼成法等、サブミクロンからミクロン（マイクロメートル）サイズの炭化ケイ素粒子であれば、アチソン法、シリカ還元法、シリコン炭化法等を用いて得ることができる。
"Precious metal particle loading process"
This is a step of preparing silicon carbide particles as a base material of catalyst particles, and supporting noble metal particles on the surface of the silicon carbide particles to form noble metal-supported silicon carbide particles.
The average primary particle diameter of the silicon carbide particles is selected in the range of 0.005 μm or more and 1 μm or less in accordance with the required characteristics of the exhaust gas purification catalyst and the exhaust gas purification device. Moreover, it is preferable to have a specific surface area as shown in the section of paint described later. The silicon carbide particles are sub-micron to micron (micrometer) size silicon carbide particles such as the thermal plasma method or the silica precursor firing method if the particles are nanometer-sized particles. It can be obtained using a method, a silica reduction method, a silicon carbonization method or the like.
この炭化ケイ素粒子の表面に、以下の方法を用いて貴金属粒子を担持し、貴金属担持炭化ケイ素粒子を形成する。
初めに、貴金属源を溶媒中に溶解した溶液、あるいは貴金属粒子を分散媒中に分散させた分散液を作製する。溶媒や分散媒は水が好適であるが、貴金属源が水で分解・沈殿するような場合には、有機溶媒を用いてもよい。この有機溶媒としては、極性溶媒が好ましく、アルコール類、ケトン類等が好適に用いられる。
この工程で用いられる貴金属源としては、白金、金、銀、ルテニウム、ロジウム、パラジウム、オスミウム、イリジウムの群から選択される１種又は２種以上の貴金属元素を含む塩類や化合物、例えば塩化物、硫酸塩、硝酸塩、有機酸塩、錯体（錯塩）、水酸化物等が挙げられる。
また、貴金属粒子としては、上記の貴金属元素を主成分とする微粒子が挙げられる。
Noble metal particles are supported on the surface of the silicon carbide particles by the following method to form noble metal-supported silicon carbide particles.
First, a solution in which a noble metal source is dissolved in a solvent or a dispersion in which noble metal particles are dispersed in a dispersion medium is prepared. The solvent or dispersion medium is preferably water, but an organic solvent may be used when the noble metal source is decomposed and precipitated with water. As the organic solvent, a polar solvent is preferable, and alcohols, ketones and the like are preferably used.
As the noble metal source used in this step, salts or compounds containing one or more kinds of noble metal elements selected from the group of platinum, gold, silver, ruthenium, rhodium, palladium, osmium, iridium, such as chlorides, Examples thereof include sulfates, nitrates, organic acid salts, complexes (complex salts), and hydroxides.
Examples of the noble metal particles include fine particles mainly composed of the above noble metal elements.
次いで、この溶液又は分散液中に炭化ケイ素粒子を浸漬や分散をさせた後、６０℃ないし２５０℃程度の温度で乾燥し、溶媒や分散媒を除去する。
別の方法として、炭化ケイ素粒子を浸漬や分散させた溶液又は分散液の特性、例えばｐＨ等を変化させて、貴金属源や貴金属微粒子を炭化ケイ素粒子の表面に選択的に析出又は凝集させた後、溶媒や分散媒を除去するようにしてもよい。
また別の方法として、炭化ケイ素粒子を浸漬や分散させた溶液に還元剤等を添加し、炭化ケイ素粒子の表面に選択的に貴金属粒子を析出させた後、溶媒や分散媒を除去するようにしてもよい。
これらの方法を単独又は組み合わせて行うことにより、炭化ケイ素粒子の表面に貴金属源や貴金属微粒子を付着させることができる。
Next, the silicon carbide particles are immersed or dispersed in this solution or dispersion, and then dried at a temperature of about 60 ° C. to 250 ° C. to remove the solvent and the dispersion medium.
As another method, after selectively precipitating or agglomerating the noble metal source or the noble metal fine particles on the surface of the silicon carbide particles by changing the properties of the solution or dispersion in which the silicon carbide particles are immersed or dispersed, such as pH, etc. The solvent and the dispersion medium may be removed.
As another method, a reducing agent or the like is added to a solution in which silicon carbide particles are immersed or dispersed, and the noble metal particles are selectively deposited on the surface of the silicon carbide particles, and then the solvent and the dispersion medium are removed. May be.
By performing these methods singly or in combination, the noble metal source and the noble metal fine particles can be attached to the surface of the silicon carbide particles.
次いで、貴金属源や貴金属微粒子が付着した炭化ケイ素粒子を、水素や一酸化炭素等を含む還元雰囲気中、あるいは窒素、アルゴン、ネオン、キセノン等の不活性雰囲気中にて熱処理する。
これにより、貴金属源は、還元・分解されて貴金属となり、生成した貴金属微粒子が炭化ケイ素粒子の表面に固着する。一方、貴金属微粒子は、還元雰囲気中や不活性雰囲気中にて熱処理しても、組成が変化することはなく、当初の微粒子の状態を維持した状態で、炭化ケイ素粒子の表面に固着する。
Next, the silicon carbide particles to which the noble metal source and the noble metal fine particles are attached are heat-treated in a reducing atmosphere containing hydrogen, carbon monoxide, or the like, or in an inert atmosphere such as nitrogen, argon, neon, or xenon.
As a result, the noble metal source is reduced and decomposed to become a noble metal, and the generated noble metal fine particles adhere to the surface of the silicon carbide particles. On the other hand, noble metal fine particles adhere to the surface of silicon carbide particles without changing the composition even when heat-treated in a reducing atmosphere or in an inert atmosphere, while maintaining the original fine particle state.
熱処理時の温度は、貴金属源や貴金属粒子の種類や雰囲気条件等により適宜選択すればよいが、５００℃以上かつ１５００℃以下が好ましく、８００℃以上かつ１２００℃以下がより好ましい。また、熱処理時の時間は、１０分以上かつ２４時間以下が好ましく、１時間以上４時間以下がより好ましい。また、熱処理は１段階でもよく、温度や雰囲気を変えた複数段階で行ってもよい。
なお、必要以上の温度や時間は、炭化ケイ素粒子の焼結や生成した貴金属粒子のシンタリングを誘発する虞があるので好ましくない。
以上の工程により、貴金属粒子担持炭化ケイ素粒子（貴金属微粒子が表面に担持された炭化ケイ素粒子）を得ることができる。
The temperature during the heat treatment may be appropriately selected depending on the type of precious metal source, precious metal particles, atmospheric conditions, and the like, but is preferably 500 ° C. or higher and 1500 ° C. or lower, and more preferably 800 ° C. or higher and 1200 ° C. or lower. The time for the heat treatment is preferably 10 minutes or longer and 24 hours or shorter, more preferably 1 hour or longer and 4 hours or shorter. Further, the heat treatment may be performed in one stage, or may be performed in a plurality of stages with different temperatures and atmospheres.
In addition, excessive temperature and time are not preferable because there is a possibility that sintering of silicon carbide particles and sintering of generated noble metal particles may be induced.
Through the above steps, noble metal particle-supported silicon carbide particles (silicon carbide particles having noble metal particles supported on the surface) can be obtained.
「酸化物層形成工程」
貴金属粒子担持炭化ケイ素粒子を酸化処理して、貴金属粒子が担持された炭化ケイ素粒子の表面に酸化物層を形成し、触媒粒子を形成する工程である。
酸化処理としては、上記の貴金属粒子が担持された炭化ケイ素粒子を、大気、酸素等の酸化性雰囲気下、６００℃以上かつ１０００℃以下、好ましくは６５０℃以上かつ９００℃以下の温度にて、０．５時間以上かつ３６時間以下、好ましくは４時間以上かつ１２時間以下、酸化処理し、炭化ケイ素粒子の表面に酸化物層を生成させる。
これにより、炭化ケイ素粒子の表面に貴金属粒子が担持され、かつこの貴金属粒子が酸化物層により覆われた状態となっている触媒粒子を形成することができる。
ここで、酸化物層を上記の条件で形成するとともに、貴金属粒子の平均一次粒径を１ｎｍ以上かつ３０ｎｍ以下としておけば、貴金属粒子が酸化物層から突き出すことなく完全に覆われた、高い触媒活性を有する触媒粒子を形成することができる。
"Oxide layer formation process"
This is a step of forming catalyst particles by oxidizing the noble metal particle-supporting silicon carbide particles to form an oxide layer on the surface of the silicon carbide particles on which the noble metal particles are supported.
As the oxidation treatment, the silicon carbide particles on which the noble metal particles are supported are at a temperature of 600 ° C. or higher and 1000 ° C. or lower, preferably 650 ° C. or higher and 900 ° C. or lower, in an oxidizing atmosphere such as air or oxygen. Oxidation treatment is performed for 0.5 hours or more and 36 hours or less, preferably 4 hours or more and 12 hours or less to form an oxide layer on the surface of the silicon carbide particles.
Thereby, the catalyst particles in which the noble metal particles are supported on the surfaces of the silicon carbide particles and the noble metal particles are covered with the oxide layer can be formed.
Here, when the oxide layer is formed under the above conditions and the average primary particle size of the noble metal particles is set to 1 nm or more and 30 nm or less, the noble metal particles are completely covered without protruding from the oxide layer. Catalyst particles having activity can be formed.
なお、貴金属粒子が酸化物層に覆われた構造にするためには、本工程を、前記「貴金属粒子担持工程」における貴金属粒子の固着処理と組み合わせて行うことが好ましい。すなわち、貴金属粒子が表面に付着した炭化ケイ素粒子を、初めに、還元雰囲気又は不活性雰囲気中、５００℃以上かつ１５００℃以下、１０分以上かつ２４時間以下で熱処理した後、引き続いて（冷却せずに）、酸化囲気中、６００℃以上かつ１０００℃以下、０．５時間以上かつ３６時間以下で熱処理を行うことが好ましい。
この、「還元雰囲気又は不活性雰囲気中で熱処理後、引き続いて酸化雰囲気中で熱処理する」という処理を行うことにより、貴金属粒子が酸化物層に覆われた本実施形態の触媒粒子を好適に形成することができる。
In order to obtain a structure in which the noble metal particles are covered with the oxide layer, this step is preferably performed in combination with the fixing treatment of the noble metal particles in the “noble metal particle supporting step”. That is, silicon carbide particles having precious metal particles attached to the surface are first heat-treated in a reducing atmosphere or an inert atmosphere at 500 ° C. or more and 1500 ° C. or less, 10 minutes or more and 24 hours or less, and subsequently (cooled). It is preferable to perform the heat treatment in an oxidizing atmosphere at 600 ° C. to 1000 ° C. for 0.5 hours to 36 hours.
By performing this treatment of “heat treatment in a reducing atmosphere or inert atmosphere and then heat treatment in an oxidizing atmosphere”, the catalyst particles of this embodiment in which noble metal particles are covered with an oxide layer are suitably formed. can do.
一方、「貴金属粒子担持工程」と「酸化物層形成工程」とを分け、間に他の工程を入れた場合、すなわち「還元雰囲気又は不活性雰囲気中で熱処理後、引き続いて酸化雰囲気中で熱処理する」という処理手順を踏まない場合には、十分な表面酸化物層が形成されなかったり、酸化物層が形成されてた場合でも、貴金属粒子が酸化物層で十分に覆われずに露出する虞がある。 On the other hand, when the “noble metal particle supporting step” and the “oxide layer forming step” are separated and other steps are put between them, that is, “heat treatment in a reducing atmosphere or inert atmosphere, followed by heat treatment in an oxidizing atmosphere” If the processing procedure of “Yes” is not followed, even if a sufficient surface oxide layer is not formed or an oxide layer is formed, the noble metal particles are not sufficiently covered with the oxide layer and exposed. There is a fear.
「塗料作製工程」
触媒粒子又は触媒粒子前駆体と造孔材とを分散媒中に分散させ、塗料を作製する工程である。
すなわち、既述の触媒粒子又は触媒粒子前駆体と、造孔材とを、分散媒中に分散させ、さらに必要に応じて、分散剤、粘度調整剤、ｐＨ調整剤、結着剤等を加えて触媒粒子又は触媒粒子前駆体と造孔材とを含む塗料を作製する工程である。
"Paint preparation process"
In this step, catalyst particles or catalyst particle precursors and a pore former are dispersed in a dispersion medium to produce a coating material.
That is, the above-described catalyst particles or catalyst particle precursor and the pore former are dispersed in a dispersion medium, and a dispersant, a viscosity modifier, a pH adjuster, a binder, etc. are added as necessary. And a coating material containing catalyst particles or a catalyst particle precursor and a pore former.
なお、ここで「触媒粒子前駆体」とは、塗料作製後の工程で触媒粒子を形成可能な粒子及び他の成分を指す。触媒粒子前駆体としては、例えば、炭化ケイ素粒子と貴金属粒子とが個別に存在するものや、炭化ケイ素粒子と貴金属源（貴金属元素を含む塩類や化合物）とを組み合わせたものが挙げられる。
以下、触媒粒子と触媒粒子前駆体を合わせて「触媒粒子等」と記す場合がある。
Here, the “catalyst particle precursor” refers to particles and other components that can form catalyst particles in the step after the preparation of the paint. Examples of the catalyst particle precursor include those in which silicon carbide particles and noble metal particles exist individually, and combinations of silicon carbide particles and noble metal sources (salts and compounds containing noble metal elements).
Hereinafter, the catalyst particles and the catalyst particle precursor may be collectively referred to as “catalyst particles”.
造孔材は、後述の「担持工程」以前に除去されるものであれば特に限定は無いが、例えば樹脂製のマイクロビーズを好適に用いることができる。また、この造孔材の塗料中の平均分散粒子径は１μｍ以上かつ２０μｍ以下が好ましい。 The pore former is not particularly limited as long as it is removed before the “supporting step” described later. For example, resin microbeads can be suitably used. Further, the average dispersed particle size in the paint of the pore former is preferably 1 μm or more and 20 μm or less.
分散工程は、湿式法によることが好ましい。また、この湿式法で用いられる分散機としては、開放型、密閉型のいずれも使用可能であり、例えば、ボールミル、攪拌ミル、ジェットミル、振動ミル、アトライター、高速ミル、ハンマーミル、等が好適に用いられる。
ボールミルとしては、転動ミル、振動ミル、遊星ミル等が挙げられ、また、攪拌ミルとしては、塔式ミル、攪拌槽型ミル、流通管式ミル、管状ミル等が挙げられる。
なお、本塗料の詳細については後述する。
The dispersing step is preferably performed by a wet method. In addition, as a disperser used in this wet method, any of an open type and a closed type can be used. For example, a ball mill, a stirring mill, a jet mill, a vibration mill, an attritor, a high speed mill, a hammer mill, etc. Preferably used.
Examples of the ball mill include a rolling mill, a vibration mill, and a planetary mill. Examples of the stirring mill include a tower mill, a stirring tank mill, a flow pipe mill, and a tubular mill.
The details of the paint will be described later.
「多孔質基材への粒子保持工程」
触媒粒子等と造孔材とを含む塗料を用いて多孔質基材からなる隔壁を処理した後、乾燥させて、触媒粒子等と造孔材とを隔壁の表面及び隔壁内部の気孔の表面に保持させる工程である。
本工程では、多孔質基材からなる隔壁に対して予め熱処理等を行い、不純物や付着物を取り除く処理をしておくことが好ましい。
"Particle retention process on porous substrate"
The partition wall made of a porous substrate is treated with a paint containing catalyst particles and a pore-forming material, and then dried, so that the catalyst particles and the pore-forming material are placed on the surface of the partition wall and the pores inside the partition wall. This is a step of holding.
In this step, it is preferable to perform a heat treatment or the like on the partition wall made of the porous base material in advance to remove impurities and deposits.
処理方法としては、ウォッシュコート法、ディップコート法等、塗料を被処理物の表面及び気孔内の表面に行き渡らせることができるウェットコート法の中から、適宜選択することができる。
ここで、１回の処理で規定量の触媒粒子等が保持されれば、処理と乾燥は１回でよく、一方１回の処理では保持量が不足する場合には、処理と乾燥を繰り返してもよい。また触媒粒子等が異なる複数の塗料を用意して順次処理−乾燥させることで、複数種の触媒粒子等を保持させてもよい。
The treatment method can be appropriately selected from wet coating methods such as a wash coating method and a dip coating method, which can spread the paint over the surface of the object to be processed and the surface in the pores.
Here, if the specified amount of catalyst particles or the like is retained in one process, the process and the drying may be performed once. On the other hand, if the retained amount is insufficient in one process, the process and the drying are repeated. Also good. Alternatively, a plurality of types of catalyst particles or the like may be held by preparing a plurality of paints having different catalyst particles or the like and sequentially treating and drying them.
処理時においては、塗料、特に分散媒の表面張力が低い場合には、多孔質基材からなる隔壁に対して単純にウェットコート法による処理を行うだけで、多孔質基材内部の気孔まで塗料が行き渡ることから、触媒粒子等と造孔材とを、隔壁の表面及び隔壁内部の気孔の表面まで全体に保持させることができる。
一方、塗料の表面張力が高い等で塗料が十分に行き渡らない場合には、例えば超音波の印加を行うことにより塗料を隔壁内の気孔内部まで行き渡らせることができる。また、多孔質基材がウォールフロー型の場合には、流入側ガス流路を塗料に浸漬させ、排出側ガス流路から吸引することにより、塗料を隔壁内の気孔内部や排出側ガス流路まで行き渡らせてもよい。
At the time of processing, when the surface tension of the coating material, especially the dispersion medium is low, the coating material can be applied to the pores inside the porous substrate by simply treating the partition wall made of the porous substrate by the wet coating method. Therefore, the catalyst particles and the pore-forming material can be held all over the surface of the partition wall and the surface of the pores inside the partition wall.
On the other hand, when the paint does not spread sufficiently due to the high surface tension of the paint, the paint can be spread to the inside of the pores in the partition walls by applying ultrasonic waves, for example. In addition, when the porous substrate is a wall flow type, the inflow side gas flow path is immersed in the paint and sucked from the discharge side gas flow path, so that the paint is inside the pores in the partition walls or the discharge side gas flow path. You may even go around.
なお、多孔質基材内部の気孔まで塗料を行き渡らせるためには、該当部分の気孔に存在する空気が抜ける必要がある。このため、特に排出側ガス流路からの吸引等を行わない場合には、多孔質基材を塗料に浸漬させる際の浸漬速度を抑えるとともに、浸漬後に一定時間以上保持して、塗料を多孔質基材内部の気孔まで十分に行き渡らせることが好ましい。好ましい浸漬速度は、多孔質基材の材質や気孔径、塗料の溶媒種や粘度等により変化するため一概にはいえないが、５ｍｍ／秒以下が好ましく、２ｍｍ／秒以下であればより好ましい。 In order to spread the paint to the pores inside the porous substrate, it is necessary to release the air present in the pores of the corresponding part. For this reason, especially when suction from the discharge-side gas flow path is not performed, the immersion rate when dipping the porous substrate in the paint is suppressed, and the paint is made porous by holding for a certain period of time after dipping. It is preferable that the pores in the substrate are sufficiently distributed. The preferable dipping speed varies depending on the material of the porous base material, the pore diameter, the solvent type and viscosity of the paint, and the like, but cannot be generally specified, but is preferably 5 mm / second or less, more preferably 2 mm / second or less.
なお、乾燥温度や時間は、分散媒が除去され、かつ造孔材が変形や消失しない温度や時間であることが好ましく、分散媒の種類や造孔材の材質により変わるが、通常、８０℃以上かつ２５０℃以下、１時間以上かつ２４時間以下である。 The drying temperature and time are preferably temperatures and times at which the dispersion medium is removed and the pore former is not deformed or lost, and it varies depending on the type of the dispersion medium and the material of the pore former. The temperature is 250 ° C. or lower and 1 hour or longer and 24 hours or shorter.
ここで、本実施形態の排ガス浄化装置がフロースルー型の場合には、多孔質基材からなる隔壁の厚さが５００μｍ程度かそれ以下であれば、処理時に特別な操作を行なったり、塗料や隔壁に特定のものを用いたりすることなく、通常のウェットコート法による処理操作で触媒粒子等を保持できる。一方、隔壁が５００μｍよりも厚い場合には、特定の方法、例えば多孔質基材を予め塗料に用いた物とは異なる分散媒に浸漬させた後半乾燥の状態とすることで隔壁の深部に分散媒を残存させておき、この状態で塗料に浸漬する方法や、塗料の粘度や表面張力を高く設定することで、隔壁の深部に塗料が入り込まないようにする方法を用いることが好ましい。また、特定の形状、例えば隔壁における気孔率を隔壁表面と深部とで変える等を行ってもよい。前述の通り、フロースルー型では排ガスが隔壁内に入り込む深さは２５０μｍ程度であるため、それより深部に触媒粒子等を保持させても、排ガス処理効果が得られないためである。 Here, when the exhaust gas purifying apparatus of the present embodiment is a flow-through type, if the partition wall made of a porous substrate has a thickness of about 500 μm or less, a special operation is performed at the time of treatment, paint or Without using a specific partition wall, catalyst particles and the like can be held by a treatment operation by a normal wet coating method. On the other hand, when the partition wall is thicker than 500 μm, it can be dispersed in the deep part of the partition wall by a specific method, for example, in the latter-half dry state in which the porous substrate is immersed in a dispersion medium different from the one previously used for the paint. It is preferable to use a method in which the medium is left and immersed in the coating in this state, or a method in which the coating does not enter the deep part of the partition wall by setting the viscosity and surface tension of the coating to be high. Further, a specific shape, for example, the porosity of the partition walls may be changed between the partition surface and the deep part. As described above, in the flow-through type, the depth at which the exhaust gas enters the partition wall is about 250 μm, so that the exhaust gas treatment effect cannot be obtained even if the catalyst particles are held deeper than that.
一方、本実施形態の排ガス浄化装置がウォールフロー型の場合には、多孔質基材からなる隔壁内部の気孔表面全体にわたって触媒粒子等が保持されてよいので、この点からは隔壁の厚さに制限は無い。しかしながら、隔壁の厚さが厚いと、浸漬時に隔壁の内部まで塗料が完全に行き渡らなくなる虞があることから、前述のように圧損が高くなることと併せて、隔壁の厚さは２００μｍ〜３００μｍ程度であることが好ましい。 On the other hand, when the exhaust gas purification apparatus of the present embodiment is a wall flow type, catalyst particles and the like may be held over the entire pore surface inside the partition wall made of a porous base material. There is no limit. However, if the partition wall is thick, there is a risk that the paint may not completely reach the inside of the partition during immersion, so that the partition wall thickness is about 200 μm to 300 μm in combination with the increase in pressure loss as described above. It is preferable that
「造孔材除去工程」
多孔質基材からなる隔壁の表面及び隔壁内の気孔の表面に保持された触媒粒子等と造孔材の内、造孔材を除去して、触媒粒子等のみを隔壁の表面及び隔壁内部の気孔の表面に残す工程である。
除去方法は造孔材の材質に合わせて選択すればよいが、例えば樹脂製のマイクロビーズを用いた場合には、加熱処理により樹脂成分を分解・揮発させたり燃焼させて除去する方法が好適に用いられる。この場合の加熱条件はマイクロビーズを形成する樹脂により選択すればよいが、通常、温度は３００℃以上かつ７５０℃以下、時間は１時間以上かつ１２時間以下である。雰囲気は、触媒粒子等を構成する炭化ケイ素粒子の酸化が起こらない範囲であれば、水素や一酸化炭素等を含む還元雰囲気、窒素、アルゴン、ネオン、キセノン等の不活性雰囲気、空気等の酸化雰囲気のいずれを選択してもよい。
また、造孔材のみが溶解し、触媒粒子等が再分散も溶出もしないような溶媒に浸漬することにより、造孔材のみを溶解除去する方法も用いることができる。
“Pore removal process”
The pore-forming material is removed from the pore-forming material and catalyst particles held on the surface of the partition walls and the pores in the partition walls, and only the catalyst particles etc. This is a step of leaving the surface of the pores.
The removal method may be selected according to the material of the pore former. For example, when resin-made microbeads are used, a method in which the resin component is decomposed, volatilized or burned by heat treatment is preferably used. Used. The heating conditions in this case may be selected depending on the resin forming the microbeads, but the temperature is usually 300 ° C. or higher and 750 ° C. or lower, and the time is 1 hour or longer and 12 hours or shorter. As long as the atmosphere is within a range where oxidation of the silicon carbide particles constituting the catalyst particles does not occur, a reducing atmosphere containing hydrogen or carbon monoxide, an inert atmosphere such as nitrogen, argon, neon, or xenon, an oxidation of air, etc. Any of the atmospheres may be selected.
Alternatively, a method of dissolving and removing only the pore former can be used by immersing in a solvent in which only the pore former is dissolved and the catalyst particles and the like are not redispersed or eluted.
なお、造孔材除去工程を加熱処理で行う場合には、次の担持工程と連続又は同時に行うことができる。ここで「連続」とは、初めに造孔材除去工程の条件で加熱処理後、続いて担持工程の条件で加熱処理を行うことを意味し、「同時」とは、当初から担持工程の条件で加熱処理することで、加熱処理の初期段階で造孔材除去工程を兼ねさせることを意味する．これらの場合、触媒粒子等を構成する炭化ケイ素粒子の酸化を防ぐために、雰囲気は還元雰囲気又は不活性雰囲気を選択することが好ましい。 In addition, when performing a pore-forming material removal process by heat processing, it can carry out continuously or simultaneously with the following supporting process. Here, “continuous” means that the heat treatment is first performed under the conditions of the pore former removing process, and then the heat treatment is performed under the conditions of the supporting process, and “simultaneous” means the conditions of the supporting process from the beginning. By heat-treating with, it means that it also serves as a pore former removing process in the initial stage of heat treatment. In these cases, in order to prevent oxidation of the silicon carbide particles constituting the catalyst particles and the like, it is preferable to select a reducing atmosphere or an inert atmosphere as the atmosphere.
「担持工程」
多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に保持された触媒粒子等を、同表面に固定して担持させる工程である。固定方法としては、水素や一酸化炭素等を含む還元雰囲気中、あるいは窒素、アルゴン、ネオン、キセノン等の不活性雰囲気中にて加熱処理し、触媒粒子等を構成する炭化ケイ素粒子と多孔質基材とを焼結させる方法が好適である。
加熱処理温度と時間は多孔質基材の材質や触媒粒子等における特性や酸化物層の形成状態、雰囲気条件等に基づいて適宜選択すればよいが、通常、温度は５００℃以上かつ１５００℃以下、好ましくは６００℃以上かつ１１００℃以下であり、時間は通常１０分以上かつ２４時間以下、好ましくは０．５時間以上かつ１２時間以下である。
なお、必要以上の温度や時間は、触媒粒子等に担持された貴金属粒子のシンタリングを誘発する虞があるので好ましくない。
"Supporting process"
In this step, the catalyst particles and the like held on the surface of the partition made of a porous substrate and the surface of the pores inside the partition are fixed and supported on the same surface. As the fixing method, heat treatment is performed in a reducing atmosphere containing hydrogen, carbon monoxide, or the like, or in an inert atmosphere such as nitrogen, argon, neon, xenon, etc., and silicon carbide particles and porous groups constituting catalyst particles, etc. A method of sintering the material is preferred.
The heat treatment temperature and time may be appropriately selected based on the material of the porous substrate, the characteristics of the catalyst particles, the formation state of the oxide layer, the atmospheric conditions, etc. The temperature is preferably from 600 ° C. to 1100 ° C., and the time is usually from 10 minutes to 24 hours, preferably from 0.5 hours to 12 hours.
An excessive temperature and time are not preferable because there is a risk of causing sintering of the noble metal particles supported on the catalyst particles or the like.
以上の工程を経ることにより、本実施形態の内燃機関の排ガス浄化装置を得ることができる。
［排ガス浄化装置作製用塗料］
次に、本実施形態の内燃機関の排ガス浄化装置を作製するための塗料を説明する。
本実施形態の塗料は、少なくとも、触媒粒子又は触媒粒子前駆体、造孔材並びに分散媒とを含有してなり、塗料が触媒粒子を含む場合、該触媒粒子の平均分散粒子径は０．１μｍ以上かつ４μｍ以下であり、塗料が触媒粒子前駆体を含む場合、該触媒粒子前駆体に含まれる炭化ケイ素粒子の平均分散粒子径は０．１μｍ以上かつ４μｍ以下である。
本実施形態の塗料は、多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に、触媒粒子を直接担持させるために用いられる。
By passing through the above process, the exhaust gas purification apparatus of the internal combustion engine of this embodiment can be obtained.
[Coating for producing exhaust gas purification equipment]
Next, the paint for producing the exhaust gas purification apparatus for the internal combustion engine of the present embodiment will be described.
The paint of this embodiment contains at least catalyst particles or a catalyst particle precursor, a pore former, and a dispersion medium. When the paint contains catalyst particles, the average dispersed particle diameter of the catalyst particles is 0.1 μm. When the coating material contains a catalyst particle precursor, the average dispersed particle diameter of the silicon carbide particles contained in the catalyst particle precursor is 0.1 μm or more and 4 μm or less.
The coating material of this embodiment is used for directly supporting catalyst particles on the surface of the partition wall made of a porous substrate and the surface of the pores inside the partition wall.
ここで、「触媒粒子」とは、炭化ケイ素粒子の表面に貴金属粒子が担持され、該貴金属粒子が、炭化ケイ素粒子表面に形成された酸化物層により覆われた状態である粒子であり、本実施形態の内燃機関の排ガス浄化装置で用いられる触媒粒子と同一である。
また、「触媒粒子前駆体」とは、塗料作製後の工程で触媒粒子を形成可能な粒子及び他の成分を指す。触媒粒子前駆体としては、例えば、炭化ケイ素粒子と貴金属粒子とが個別に存在するものや、炭化ケイ素粒子と貴金属源（貴金属元素を含む塩類や化合物）とを組み合わせたものが挙げられる。
本実施形態の排ガス浄化装置作成用塗料における触媒粒子前駆体は、本実施形態の排ガス浄化装置の製造方法における触媒粒子前駆体と同じものを用いることができる。
なお、本実施形態の塗料の説明においても、触媒粒子と触媒粒子前駆体とを合わせて「触媒粒子等」と記す場合がある。
Here, the “catalyst particles” are particles in which noble metal particles are supported on the surface of the silicon carbide particles and the noble metal particles are covered with an oxide layer formed on the surface of the silicon carbide particles. It is the same as the catalyst particles used in the exhaust gas purification apparatus for an internal combustion engine of the embodiment.
Further, the “catalyst particle precursor” refers to particles and other components that can form catalyst particles in the process after the preparation of the paint. Examples of the catalyst particle precursor include those in which silicon carbide particles and noble metal particles exist individually, and combinations of silicon carbide particles and noble metal sources (salts and compounds containing noble metal elements).
As the catalyst particle precursor in the paint for producing an exhaust gas purification apparatus of the present embodiment, the same catalyst particle precursor as that in the method for manufacturing the exhaust gas purification apparatus of the present embodiment can be used.
In the description of the paint of this embodiment, the catalyst particles and the catalyst particle precursor may be collectively referred to as “catalyst particles and the like”.
この触媒粒子や触媒粒子前駆体に用いられる炭化ケイ素粒子としては、平均一次粒子径が０．００５μｍ以上かつ１μｍ以下であることが好ましく、０．０２μｍ以上かつ０．８５μｍ以下がより好ましく、０．０３５μｍ以上かつ０．６μｍ以下であればさらに好ましい。 The silicon carbide particles used in the catalyst particles and catalyst particle precursors preferably have an average primary particle size of 0.005 μm or more and 1 μm or less, more preferably 0.02 μm or more and 0.85 μm or less, and More preferably, it is 035 μm or more and 0.6 μm or less.
また、この炭化ケイ素粒子に担持される貴金属粒子としては、白金、金、銀、ルテニウム、ロジウム、パラジウム、オスミウム、イリジウムの群から選択される１種又は２種以上を含有していることが好ましく、浄化対象とする物質（炭化水素系有機物：ＨＣ、一酸化炭素：ＣＯ、窒素酸化物：ＮＯｘ、粒子状物質：ＰＭ）を考慮した上で選択することが好ましい。例えば、ＰＭ燃焼等の酸化触媒作用を有する貴金属としては、白金、パラジウム、ロジウム等から選択される１種ないし２種以上を用いることができる。また、ＮＯｘ還元触媒としてはパラジウム、イリジウム等やこれら貴金属粒子と各種の化合物粒子を組み合わせて用いることができる。この貴金属粒子の一次粒子径は１ｎｍ以上かつ３０ｎｍ以下が好ましく、１ｎｍ以上かつ２０ｎｍ以下がより好ましく、１ｎｍ以上かつ１０ｎｍ以下であればさらに好ましい。そして、この貴金属粒子は、炭化ケイ素粒子表面に形成された酸化物層により覆われている。 The noble metal particles supported on the silicon carbide particles preferably contain one or more selected from the group consisting of platinum, gold, silver, ruthenium, rhodium, palladium, osmium and iridium. It is preferable to select the substance to be purified in consideration of the substance to be purified (hydrocarbon organic substance: HC, carbon monoxide: CO, nitrogen oxide: NO x , particulate substance: PM). For example, as the noble metal having an oxidation catalytic action such as PM combustion, one or more selected from platinum, palladium, rhodium, and the like can be used. In addition, as the NO x reduction catalyst, palladium, iridium or the like, or a combination of these noble metal particles and various compound particles can be used. The primary particle size of the noble metal particles is preferably 1 nm to 30 nm, more preferably 1 nm to 20 nm, and even more preferably 1 nm to 10 nm. The noble metal particles are covered with an oxide layer formed on the surface of the silicon carbide particles.
次に、触媒粒子では、この炭化ケイ素粒子の表面には酸化物層が形成されている。酸化物層の厚さは２０ｎｍ以下が好ましい。酸化物層の厚さは、前述の貴金属粒子を完全に覆うという観点からは厚い方が良いが、一方、酸化物層が厚すぎると貴金属粒子による触媒効果を減じてしまうことから、２０ｎｍ以下の厚さが選択される。 Next, in the catalyst particles, an oxide layer is formed on the surface of the silicon carbide particles. The thickness of the oxide layer is preferably 20 nm or less. The thickness of the oxide layer is preferably thick from the viewpoint of completely covering the above-mentioned noble metal particles. On the other hand, if the oxide layer is too thick, the catalytic effect by the noble metal particles is reduced. The thickness is selected.
また、この酸化物層は、非晶質のＳｉＯｘＣｙ（ただし、０＜ｘ≦３、０≦ｙ≦３）を含有してなることが好ましく、さらには、ＳｉＯ２、ＳｉＯ、ＳｉＯＣ３、ＳｉＯ２Ｃ２及びＳｉＯ３Ｃの群から選択される１種又は２種以上の結晶質を含有していてもよい。
なお、この酸化物層の組成や構造は単一である必要はなく、酸化物層の各部分におけるｘ及びｙの値は上記の範囲内で任意の値を取ることができる。
The oxide layer preferably contains amorphous SiO x C y (where 0 <x ≦ 3, 0 ≦ y ≦ 3). Furthermore, SiO 2 , SiO, SiOC 3 , SiO 2 C 2 and SiO 3 C may be selected from one or two or more crystalline materials.
Note that the composition and structure of the oxide layer do not have to be single, and the values of x and y in each part of the oxide layer can take arbitrary values within the above range.
ここで、本実施形態の塗料における触媒粒子等の含有率（触媒粒子等の質量／塗料の質量）は０．１質量％以上かつ１０質量％以下であることが好ましい。触媒粒子等の含有率が０．１質量％未満では、多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に担持できる触媒粒子の量が少なすぎるために、十分な排ガス処理能力を持たせるためには複数回の浸漬・乾燥等の処理が必要となり、コストの増大を招く虞がある。一方、触媒粒子等の含有率が１０質量％を超えた場合には、造孔材の含有量にもよるが一般的に塗料の粘度が高くなりすぎるために、塗料自体が多孔質基材からなる隔壁の内部に入り込みにくくなり、その結果、多孔質基材の気孔内表面に触媒粒子が十分に担持されない虞があり好ましくないためである。
触媒粒子等の含有率（触媒粒子等の質量／塗料の質量）は１質量％以上かつ３質量％以下であればより好ましい。
Here, the content of catalyst particles and the like (mass of catalyst particles / mass of paint / mass of paint) in the paint of this embodiment is preferably 0.1% by mass or more and 10% by mass or less. If the content of the catalyst particles or the like is less than 0.1% by mass, the amount of catalyst particles that can be supported on the surface of the partition wall made of a porous substrate and the surface of the pores inside the partition wall is too small. In order to have it, a plurality of treatments such as dipping and drying are required, which may increase the cost. On the other hand, when the content of the catalyst particles and the like exceeds 10% by mass, the viscosity of the paint is generally too high although it depends on the content of the pore former. This is because it is difficult to enter the inside of the partition wall, and as a result, the catalyst particles may not be sufficiently supported on the pore inner surface of the porous substrate.
The content of catalyst particles and the like (mass of catalyst particles and the like / mass of paint) is more preferably 1% by mass to 3% by mass.
次に造孔材だが、この造孔材は、触媒粒子等と共に多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に付着した後、揮発、分解、燃焼等により除去することにより、触媒粒子が多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面のそれぞれ一部のみに担持されることを目的として使用される。従って、造孔材としては、塗料中で沈降することなく分散状態を維持できること、本塗料を用いて多孔質基材への粒子保持を行う際においては触媒粒子等と同様の挙動を示し、多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に保持されること、該造孔材を除去する際には触媒粒子等を残して選択的に除去されること、といった特性を有することが必要である。 Next, the pore former is adhered to the surface of the partition wall made of a porous substrate together with catalyst particles and the pore surface inside the partition wall, and then removed by volatilization, decomposition, combustion, etc. The catalyst particles are used for the purpose of being supported on only a part of the surface of the partition wall made of a porous substrate and the surface of the pores inside the partition wall. Therefore, as a pore former, it is possible to maintain a dispersed state without settling in the paint, and when the particles are retained on the porous substrate using this paint, it exhibits the same behavior as the catalyst particles, etc. It has the characteristics that it is retained on the surface of the partition wall made of a porous substrate and the surface of the pores inside the partition wall, and when the pore former is removed, it is selectively removed leaving catalyst particles, etc. is necessary.
造孔材の材質としては、上記の特性を発現できるものであれば特に限定はされないが、グラファイト等の炭素材；ポリエチレン、ポリプロピレン、ポリメタクリル酸メチル等の樹脂類：でんぷん、ナッツ殻、クルミ殻、コーンなどの食物材料；氷；及びドライアイス等を挙げることができる。これらの中でも、除去するための条件である分解温度等の制御が容易な樹脂材料が好ましい。また、塗料作製時の混練等、ある程度の力がかかっても変形しないほうが良いことから、特に硬質樹脂を好適に用いることができる。 The material of the pore former is not particularly limited as long as it can exhibit the above characteristics, but carbon materials such as graphite; resins such as polyethylene, polypropylene, and polymethyl methacrylate: starch, nut shell, walnut shell And food materials such as corn; ice; and dry ice. Among these, a resin material that can easily control the decomposition temperature, which is a condition for removal, is preferable. In addition, since it is better not to be deformed even when a certain amount of force is applied, such as kneading at the time of preparing the paint, a hard resin can be particularly preferably used.
また、この造孔材は触媒粒子等とともに多孔質基材の気孔内に入り込む必要があることから、塗料中の平均分散粒子径は多孔質基材の平均気孔径の１／２以下であることが好ましく、１／４以下であればさらに好ましい。一方、造孔材の平均分散粒子径が触媒粒子等の平均分散粒子径よりも大幅に小さくなると、触媒粒子等と共に多孔質基材に保持させた際に造孔材が押し出され、造孔材を用いる効果が低下する虞があることから、造孔材の平均分散粒子径は、触媒粒子等の平均分散粒子径の１／４よりも大きいことが好ましく、１／２よりも大きければさらに好ましい。 In addition, since the pore former needs to enter the pores of the porous substrate together with the catalyst particles and the like, the average dispersed particle size in the coating material should be 1/2 or less of the average pore size of the porous substrate. Is preferable, and it is more preferable if it is 1/4 or less. On the other hand, when the average dispersed particle diameter of the pore former is significantly smaller than the average dispersed particle diameter of the catalyst particles, the pore former is extruded when held on the porous substrate together with the catalyst particles, etc. The average dispersed particle diameter of the pore former is preferably larger than 1/4 of the average dispersed particle diameter of catalyst particles and the like, and more preferably larger than 1/2. .
ここで、通常の多孔質基材では、平均気孔径が１０μｍ以上かつ５０μｍ以下であること、また、後述のように触媒粒子等の平均分散粒子径が０．１μｍ以上かつ４μｍであることを考慮すると、造孔材の平均分散粒子径は１μｍ以上かつ２０μｍ以下であることが好ましく、３μｍ以上かつ１０μｍ以下であればさらに好ましい。
以上のように、除去するための条件制御が容易であること、また粒子径を容易に制御できることを考慮すると、造孔材としては、樹脂製のマイクロビーズが好適に用いられる。
Here, in the case of a normal porous substrate, it is considered that the average pore diameter is 10 μm or more and 50 μm or less, and that the average dispersed particle diameter of catalyst particles and the like is 0.1 μm or more and 4 μm as described later. Then, the average dispersed particle size of the pore former is preferably 1 μm or more and 20 μm or less, and more preferably 3 μm or more and 10 μm or less.
As described above, considering that the condition control for removal is easy and that the particle diameter can be easily controlled, resin-made microbeads are preferably used as the pore former.
また、本実施形態の塗料における触媒粒子等と造孔材との質量比（触媒粒子等の質量：造孔材の質量）は、多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に対する触媒粒子の担持量、塗料中の触媒粒子等及び造孔材の含有率、塗料中の触媒粒子等及び造孔材の平均分散粒子径、等の条件により変わるため一概には言えないが、１：１０から１０：１の範囲が好ましい。 In addition, the mass ratio between the catalyst particles and the pore former in the coating material of the present embodiment (the mass of the catalyst particles and the like: the mass of the pore former) is the surface of the partition wall made of the porous substrate and the surface of the pores inside the partition wall The amount of catalyst particles to be supported, the content of the catalyst particles and the pore former in the paint, the average dispersed particle size of the catalyst particles and the pore former in the paint, etc. A range of 1:10 to 10: 1 is preferred.
ここで、触媒粒子等の量が造孔材量の１０倍を超えた場合には、多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面において触媒粒子同士が集合体を形成してしまい、結果として触媒粒子の一部が多孔質基材の表面及び気孔内表面に直接担持されなくなるだけでなく、集合体内部の触媒粒子が排ガスと十分に接しないために、触媒能を発現できなくなる虞がある。一方、造孔材量が触媒粒子等の量の１０倍を超えた場合には、多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に担持されたおける触媒粒子量が少なすぎるために、十分な排ガス処理能力が発現できなくなる虞がある。
触媒粒子等と造孔材との比率（触媒粒子等の質量：塗料の質量）は、５：１から１：５の範囲であればより好ましく、２：１から１：２の範囲であればさらに好ましい。
Here, when the amount of the catalyst particles exceeds 10 times the amount of the pore former, the catalyst particles form aggregates on the surface of the partition wall made of the porous substrate and the surface of the pores inside the partition wall. As a result, a part of the catalyst particles is not directly supported on the surface of the porous substrate and the inner surface of the pores, and the catalyst particles in the aggregate do not sufficiently contact the exhaust gas, so that the catalytic ability can be expressed. There is a risk of disappearing. On the other hand, if the amount of pore former exceeds 10 times the amount of catalyst particles, etc., the amount of catalyst particles supported on the surface of the partition wall made of the porous substrate and the surface of the pores inside the partition wall is too small. In addition, there is a possibility that sufficient exhaust gas treatment capacity cannot be expressed.
The ratio of the catalyst particles and the like to the pore former (mass of catalyst particles: mass of paint) is more preferably in the range of 5: 1 to 1: 5, and is preferably in the range of 2: 1 to 1: 2. Further preferred.
また分散媒としては、水又は有機溶媒が好適に用いられる。その他、必要に応じて、高分子モノマーやオリゴマーの単体もしくはこれらの混合物も用いることができる。 As the dispersion medium, water or an organic solvent is preferably used. In addition, polymer monomers and oligomers alone or a mixture thereof can be used as necessary.
上記の有機溶媒としては、例えば、メタノール、エタノール、１−プロパノール、２−プロパノール、ジアセトンアルコール、フルフリルアルコール、エチレングリコール、ヘキシレングリコール等のアルコール類、酢酸メチルエステル、酢酸エチルエステル等のエステル類、ジエチルエーテル、エチレングリコールモノメチルエーテル（メチルセロソルブ）、エチレングリコールモノエチルエーテル（エチルセロソルブ）、エチレングリコールモノブチルエーテル（ブチルセロソルブ）、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、エチレングリコールモノエチルエーテル等のエーテルアルコール類、ジオキサン、テトラヒドロフラン等のエーテル類、アセトン、メチルエチルケトン、アセチルアセトン、アセト酢酸エステル等のケトン類、Ｎ，Ｎ−ジメチルホルムアミド等の酸アミド類、トルエン、キシレン等の芳香族炭化水素等が好適に用いられ、これらの溶媒のうち１種のみ、又は２種以上を混合して用いることができる。 Examples of the organic solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, diacetone alcohol, furfuryl alcohol, ethylene glycol and hexylene glycol, and esters such as methyl acetate and ethyl acetate. Ether ether such as diethyl ether, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monoethyl ether , Ethers such as dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, acetyl Preferably used are ketones such as seton and acetoacetate, acid amides such as N, N-dimethylformamide, aromatic hydrocarbons such as toluene and xylene, and only one or two of these solvents. The above can be mixed and used.
また、上記の高分子モノマーとしては、アクリル酸メチル、メタクリル酸メチル等のアクリル系又はメタクリル系のモノマー、エポキシ系モノマー等が好適に用いられる。また、上記のオリゴマーとしては、ウレタンアクリレート系オリゴマー、エポキシアクリレート系オリゴマー、アクリレート系オリゴマー等が好適に用いられる。
これらの分散媒のうち、塗料用として好ましいものは、水、アルコール類、ケトン類であり、これらの中でも、水、アルコール類がより好ましく、水が最も好ましい。
Moreover, as said high molecular monomer, acrylic-type or methacryl-type monomers, such as methyl acrylate and methyl methacrylate, an epoxy-type monomer, etc. are used suitably. Moreover, as said oligomer, a urethane acrylate oligomer, an epoxy acrylate oligomer, an acrylate oligomer etc. are used suitably.
Among these dispersion media, water, alcohols, and ketones are preferable for coating materials, and among these, water and alcohols are more preferable, and water is most preferable.
この塗料は、触媒粒子等を多孔質基材に保持させる際に、多孔質基材との間にバインダー機能を持たせる等のため、親水性あるいは疎水性の高分子等を適宜含有してもよい。この高分子等は、上記の分散媒に溶解し、かつ塗料中の触媒粒子等の平均分散粒子径、塗料の粘度及びｐＨが所望の値を逸脱しない範囲であれば適宜選択することができる。 This paint may contain a hydrophilic or hydrophobic polymer as appropriate in order to provide a binder function with the porous substrate when the catalyst particles are held on the porous substrate. Good. The polymer or the like can be appropriately selected as long as it dissolves in the above-described dispersion medium and the average dispersed particle diameter of the catalyst particles and the like in the paint, the viscosity and pH of the paint do not deviate from desired values.
ここで、水を分散媒とした場合、親水性高分子としては、例えば、ポリビニルアルコール、ポリビニルピロリドン、ポリエチレングリコール、ポリアクリルアミド、ポリスチレンスルホン酸、ポリアクリル酸ポリビニルビロリドン、ポリアリルアミン等の合成高分子；セルロース、デキストリン、デキストラン、デンプン、キトサン、ペクチン、アガロース、カラギーナン、キチン、マンナン等の多糖類及び多糖類由来の物質等の天然高分子；ゼラチン、カゼイン、コラーゲン、ラミニン、フィブロネクチン、エラスチン等のタンパク質及びタンパク質由来の物質等を用いることができる。
また、これら合成高分子、多糖類、タンパク質等を由来とするゲル、ゾル等の物質を用いることもできる。
Here, when water is used as a dispersion medium, examples of hydrophilic polymers include synthetic alcohols such as polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, polyacrylamide, polystyrene sulfonic acid, polyvinyl pyrrolidone polyacrylate, and polyallylamine. Molecules: Natural polymers such as polysaccharides and polysaccharide-derived substances such as cellulose, dextrin, dextran, starch, chitosan, pectin, agarose, carrageenan, chitin, mannan; gelatin, casein, collagen, laminin, fibronectin, elastin, etc. Proteins and protein-derived substances can be used.
Further, substances such as gels and sols derived from these synthetic polymers, polysaccharides, proteins and the like can also be used.
なお、この塗料における触媒粒子等の質量に対する親水性あるいは疎水性の高分子の質量の比（高分子の質量／微粒子の質量）は、塗料中の触媒粒子等の平均分散粒子径、塗料の粘度及びｐＨが所望の値になる範囲で適宜選択することができるが、１以下であることが好ましく、０．８以下がより好ましく、０．５以下さあればさらに好ましい。
用いる親水性高分子は、「造孔材除去工程」や「担持工程」において最終的に消失し、多孔質膜には残存しない成分、すなわち造孔材と同様の効果も有する成分である。そのため、上記の比が１を超えると、高分子の含有率が高すぎ、本実施形態の塗料を用いて作製された排ガス浄化装置において、触媒粒子と多孔質基材との結合力や触媒粒子同士の結合力が低下し、触媒粒子が多孔質基材から脱落しやすくなる虞がある。また、コストの上昇も招くことになり好ましくない。なお、親水性あるいは疎水性の高分子は必ずしも用いる必要はないため、範囲の下限値は０となる。
The ratio of the mass of the hydrophilic or hydrophobic polymer to the mass of the catalyst particles in the paint (the mass of the polymer / the mass of the fine particles) is the average dispersed particle size of the catalyst particles in the paint, the viscosity of the paint. In addition, the pH can be appropriately selected within a range where the pH becomes a desired value, but it is preferably 1 or less, more preferably 0.8 or less, and even more preferably 0.5 or less.
The hydrophilic polymer to be used is a component that finally disappears in the “pore-forming material removing step” or “supporting step” and does not remain in the porous membrane, that is, a component that has the same effect as the pore-forming material. Therefore, when the above ratio exceeds 1, the content of the polymer is too high, and in the exhaust gas purification apparatus produced using the coating material of the present embodiment, the binding force between the catalyst particles and the porous substrate or the catalyst particles There is a possibility that the bonding force between them decreases, and the catalyst particles easily fall off the porous substrate. In addition, the cost increases, which is not preferable. It is not always necessary to use a hydrophilic or hydrophobic polymer, so the lower limit of the range is zero.
また、この塗料の分散安定性を確保したり、あるいは塗布性を向上させたりするために、界面活性剤、防腐剤、安定化剤、消泡剤、レベリング剤等を適宜添加してもよい。これら添加剤の種類及び添加量は、塗料中の触媒粒子等の平均分散粒子径、塗料の粘度及び塗料のｐＨが所望の範囲になるように適宜選択して使用することができる。これら界面活性剤、防腐剤、安定化剤、消泡剤、レベリング剤等の添加量に特に制限はなく、塗料の粘度及び塗料中の微粒子の平均二次粒子径が本発明の範囲内となるように、添加する目的に応じて加えればよい。ただし、添加量が過多になると、上記の親水性あるいは疎水性の高分子と同様の好ましくない効果を示すようになるから、添加量を必要以上に多くすることは好ましくない。 Further, in order to ensure the dispersion stability of the paint or to improve the coating property, a surfactant, preservative, stabilizer, antifoaming agent, leveling agent and the like may be appropriately added. The types and addition amounts of these additives can be appropriately selected and used so that the average dispersed particle diameter of catalyst particles and the like in the paint, the viscosity of the paint and the pH of the paint are in a desired range. There are no particular restrictions on the amount of these surfactants, preservatives, stabilizers, antifoaming agents, leveling agents and the like, and the viscosity of the paint and the average secondary particle size of the fine particles in the paint are within the scope of the present invention. Thus, what is necessary is just to add according to the objective to add. However, if the addition amount is excessive, the same undesirable effect as the above hydrophilic or hydrophobic polymer is exhibited, so it is not preferable to increase the addition amount more than necessary.
次に、本実施形態の塗料の特性について説明する。以下の説明では、「触媒粒子」及び「触媒粒子前駆体に含まれる炭化ケイ素粒子」という２種の粒子を併記する場合、「触媒粒子又は触媒粒子前駆体に含まれる炭化ケイ素粒子」を、単に「触媒粒子又は炭化ケイ素粒子」と略記することがある。 Next, the characteristics of the paint of this embodiment will be described. In the following description, when two types of particles, “catalyst particles” and “silicon carbide particles contained in a catalyst particle precursor” are described together, “silicon carbide particles contained in catalyst particles or catalyst particle precursors” are simply It may be abbreviated as “catalyst particles or silicon carbide particles”.
本実施形態の塗料では、触媒粒子又は炭化ケイ素粒子の平均分散粒子径は０．１μｍ以上かつ４μｍ以下である。その理由として、この塗料を用いて平均気孔径が１０μｍ以上かつ５０μｍ以下の多孔質基材に触媒粒子等を担持する場合において、塗料中の触媒粒子又は炭化ケイ素粒子の平均分散粒子径が０．１μｍを下回ると、多孔質基材を塗料に浸漬した後に過剰の塗料を除去する際に触媒粒子又は炭化ケイ素粒子が溶媒と共に流出してしまい、その結果、多孔質基材の表面及び気孔内表面に触媒粒子が十分に担持されない虞があり好ましくないためである。一方、触媒粒子又は炭化ケイ素粒子の平均分散粒子径が４μｍを超えると、触媒粒子又は炭化ケイ素粒子が多孔質基材の内部に入り込みにくくなることから、多孔質基材の表面に触媒粒子等からなる多孔質膜が形成されてしまい、多孔質基材の表面及び気孔内表面に触媒粒子を直接担持することが難しくなり好ましくないからである。
なお、塗料中の触媒粒子又は炭化ケイ素粒子の平均分散粒子径は、０．１μｍ以上かつ２μｍ以下が好ましく、０．１μｍ以上かつ１μｍ以下であればより好ましい。
In the coating material of this embodiment, the average dispersed particle size of the catalyst particles or silicon carbide particles is 0.1 μm or more and 4 μm or less. The reason for this is that when the catalyst particles are supported on a porous substrate having an average pore size of 10 μm or more and 50 μm or less using this coating material, the average dispersed particle size of the catalyst particles or silicon carbide particles in the coating material is 0.00. When the thickness is less than 1 μm, catalyst particles or silicon carbide particles flow out together with the solvent when the excess paint is removed after the porous base material is immersed in the paint. As a result, the surface of the porous base material and the pore inner surface This is because there is a possibility that the catalyst particles may not be sufficiently supported. On the other hand, if the average dispersed particle diameter of the catalyst particles or silicon carbide particles exceeds 4 μm, the catalyst particles or silicon carbide particles are difficult to enter the inside of the porous substrate. This is because it becomes difficult to directly support the catalyst particles on the surface of the porous substrate and the inner surface of the pores.
The average dispersed particle size of the catalyst particles or silicon carbide particles in the coating is preferably 0.1 μm or more and 2 μm or less, and more preferably 0.1 μm or more and 1 μm or less.
また、多孔質基材からなる隔壁の表面及び隔壁内部の気孔の表面に触媒粒子を直接担持するためには、塗料に含まれる触媒粒子又は炭化ケイ素粒子の比表面積、塗料の粘度及び塗料のｐＨが調整されていることが好ましい。
ここで、触媒粒子又は炭化ケイ素粒子の比表面積は１ｍ２／ｇ以上かつ１２５ｍ２／ｇ以下が好ましい。その理由として、塗料に含まれる触媒粒子又は炭化ケイ素粒子の比表面積が１２５ｍ２／ｇを超えると、触媒粒子又は炭化ケイ素粒子の表面活性が高いために粒子が凝集してしまうために平均分散粒子径が４μｍ以上となり易く、その結果、触媒粒子等が多孔質基材の内部に入り込みにくくなる。さらに、塗料の粘度も上昇してしまうために、塗料が多孔質基材の気孔内に十分に浸漬できなくなる。これらの結果、多孔質基材の表面及び気孔内表面に触媒粒子を直接担持することが難しくなり好ましくない。一方、触媒粒子又は炭化ケイ素粒子の比表面積が１ｍ２／ｇ未満であると、触媒粒子又は炭化ケイ素粒子の一次粒子径が過大となるために塗料中の平均分散粒子径が４μｍ以上となり易く、さらに一次粒子径が過大なために粒子沈降を招くことから塗料の安定性が低下して良好な塗料を得るのが難しくなり好ましくない。
なお、触媒粒子又は炭化ケイ素粒子の比表面積は３ｍ２／ｇ以上かつ１００ｍ２／ｇ以下がより好ましく、２０ｍ２／ｇ以上かつ８０ｍ２／ｇ以下であればさらに好ましい。
In addition, in order to directly support the catalyst particles on the surface of the partition wall made of a porous substrate and the surface of the pores inside the partition wall, the specific surface area of the catalyst particles or silicon carbide particles contained in the paint, the viscosity of the paint and the pH of the paint Is preferably adjusted.
Here, the specific surface area of the catalyst particles or silicon carbide particles is preferably 1 m 2 / g or more and 125 m 2 / g or less. The reason is that if the specific surface area of the catalyst particles or silicon carbide particles contained in the paint exceeds 125 m 2 / g, the particles are aggregated because the surface activity of the catalyst particles or silicon carbide particles is high, so the average dispersed particles The diameter is likely to be 4 μm or more, and as a result, the catalyst particles and the like are difficult to enter the porous substrate. Furthermore, since the viscosity of the paint also increases, the paint cannot be sufficiently immersed in the pores of the porous substrate. As a result, it becomes difficult to directly support the catalyst particles on the surface of the porous substrate and the inner surface of the pores. On the other hand, when the specific surface area of the catalyst particles or silicon carbide particles is less than 1 m 2 / g, the primary particle diameter of the catalyst particles or silicon carbide particles becomes excessive, so the average dispersed particle diameter in the paint tends to be 4 μm or more, Further, since the primary particle size is excessive, particle sedimentation is caused, so that the stability of the coating material is lowered and it becomes difficult to obtain a good coating material, which is not preferable.
The specific surface area of the catalyst particles or silicon carbide particles is more preferably 3 m 2 / g to 100 m 2 / g, and even more preferably 20 m 2 / g to 80 m 2 / g.
次に、塗料の粘度は、２ｍＰａ・ｓ以上かつ１００ｍＰａ・ｓ以下が好ましい。その理由として、この塗料を用いて平均気孔径が１０μｍ以上かつ５０μｍ以下の多孔質基材に触媒粒子等を担持する場合において、塗料の粘度が２ｍＰａ・ｓ未満であると、多孔質基材を塗料に浸漬した後過剰の塗料を除去する際に触媒粒子等が溶媒と共に流出してしまい、多孔質基材の表面及び気孔内表面に触媒粒子が十分に担持されない虞があり好ましくないためである。一方、粘度が１００ｍＰａ・ｓを超えると、塗料自体が多孔質基材からなる隔壁の内部に入り込みにくくなり、その結果、多孔質基材の気孔内表面に触媒粒子が十分に担持されない虞があり好ましくないためである。
なお、塗料の粘度は２ｍＰａ・ｓ以上かつ５０ｍＰａ・ｓ以下がより好ましく、２ｍＰａ・ｓ以上かつ１０ｍＰａ・ｓ以下でればさらに好ましい。
Next, the viscosity of the paint is preferably 2 mPa · s or more and 100 mPa · s or less. The reason is that when the catalyst particles are supported on a porous substrate having an average pore diameter of 10 μm or more and 50 μm or less using this coating material, the viscosity of the coating material is less than 2 mPa · s. This is because when the excess paint is removed after being immersed in the paint, the catalyst particles and the like flow out together with the solvent, and the catalyst particles may not be sufficiently supported on the surface of the porous substrate and the pore inner surface. . On the other hand, if the viscosity exceeds 100 mPa · s, the coating itself is difficult to enter the partition wall made of the porous substrate, and as a result, the catalyst particles may not be sufficiently supported on the pore inner surface of the porous substrate. It is because it is not preferable.
The viscosity of the paint is more preferably 2 mPa · s to 50 mPa · s, and even more preferably 2 mPa · s to 10 mPa · s.
次に、塗料のｐＨは７以上であることが好ましい。その理由として、触媒粒子又は炭化ケイ素粒子は主成分が炭化ケイ素であるため、等電点の関係から、塗料のｐＨが７以上（中性〜アルカリ性）の範囲であれば触媒粒子又は炭化ケイ素粒子の凝集が抑えられ、平均分散粒子径が４μｍ以下の良好な分散状態が維持されるためである。これに対し、ｐＨが７未満（酸性）では触媒粒子又は炭化ケイ素粒子が擬似的な凝集を起こし、結果として平均分散粒子径が４μｍを超える状態となるために、触媒粒子又は炭化ケイ素粒子が多孔質基材の内部に入り込みにくくなるため好ましくない。
なお、ｐＨが必要以上に高くなると、塗料中に過剰に存在する水酸化物イオン（ＯＨ−）が有機成分に影響をあたえる虞が生じること等から、ｐＨは７以上かつ１２以下が好ましく、７以上かつ１０以下であればさらに好ましい。
Next, the pH of the paint is preferably 7 or more. The reason is that the catalyst particles or silicon carbide particles are mainly composed of silicon carbide. Therefore, from the relation of isoelectric point, if the pH of the coating is in the range of 7 or more (neutral to alkaline), the catalyst particles or silicon carbide particles This is because agglomeration is suppressed and a good dispersion state with an average dispersed particle diameter of 4 μm or less is maintained. On the other hand, when the pH is less than 7 (acidic), the catalyst particles or silicon carbide particles cause pseudo aggregation, and as a result, the average dispersed particle diameter exceeds 4 μm, so that the catalyst particles or silicon carbide particles are porous. This is not preferable because it is difficult to enter the inside of the base material.
In addition, when pH becomes higher than necessary, hydroxide ions (OH − ) excessively present in the paint may affect the organic component, and therefore the pH is preferably 7 or more and 12 or less. More preferably, it is 10 or less.
ここで、ｐＨ制御剤としては、酸成分であれば酢酸、プロピオン酸等の有機酸が、アルカリ成分であればアンモニア（水溶液）や有機アミンを好適に用いることができ、特に酢酸及びアンモニアが好ましい。ｐＨ制御剤が有機酸、アンモニア及び有機アミンであれば、本塗料を用いて多孔質基材からなる隔壁を処理した後の熱処理工程で、これらｐＨ制御剤を完全に除去できるので、その後の処理工程や触媒粒子の特性に影響を及ぼす虞が無い。 Here, as the pH control agent, an organic acid such as acetic acid or propionic acid can be suitably used if it is an acid component, and ammonia (aqueous solution) or an organic amine can be suitably used if it is an alkaline component, with acetic acid and ammonia being particularly preferred. . If the pH control agent is an organic acid, ammonia, or organic amine, these pH control agents can be completely removed in the heat treatment step after treating the partition wall made of the porous substrate with this paint, so that the subsequent treatment There is no risk of affecting the characteristics of the process and catalyst particles.
一方、ｐＨ制御剤として無機酸を用いた場合には、その後の熱処理工程等で陰イオンに起因する腐食性ガス（例えば、塩酸を用いた場合には塩素ガス）が発生する虞があり、またアンモニア以外の無機アルカリを用いた場合には、その後の処理を行った後でも陽イオン成分（例えば、水酸化ナトリウムであればナトリウム）が残留する虞がある。そして、これらの腐食性ガスや残留成分は、触媒粒子の特性に影響を及ぼす虞がある。よって、ｐＨ制御剤として無機酸やアンモニア以外の無機アルカリを使用することは好ましくない。 On the other hand, when an inorganic acid is used as the pH control agent, corrosive gas (for example, chlorine gas when hydrochloric acid is used) due to anions may be generated in the subsequent heat treatment process, etc. When an inorganic alkali other than ammonia is used, a cation component (for example, sodium for sodium hydroxide) may remain even after the subsequent treatment. These corrosive gases and residual components may affect the characteristics of the catalyst particles. Therefore, it is not preferable to use an inorganic alkali other than an inorganic acid or ammonia as a pH control agent.
以上のような各成分、すなわち、触媒粒子又は触媒粒子前駆体、造孔材並びにｐＨ制御剤を分散媒中に分散及び溶解させて、塗料とする。この分散工程は、湿式法によることが好ましい。また、この湿式法で用いられる分散機としては、開放型、密閉型のいずれも使用可能であり、例えば、ボールミル、攪拌ミル、ジェットミル、振動ミル、アトライター、高速ミル、ハンマーミル、等が好適に用いられる。ボールミルとしては、転動ミル、振動ミル、遊星ミル等が挙げられ、また、攪拌ミルとしては、塔式ミル、攪拌槽型ミル、流通管式ミル、管状ミル等が挙げられる。
また、必要に応じて、親水性あるいは疎水性の高分子、界面活性剤、防腐剤、安定化剤、消泡剤、レベリング剤等を加えてもよい。
Each component as described above, that is, catalyst particles or catalyst particle precursor, pore former and pH control agent is dispersed and dissolved in a dispersion medium to obtain a paint. This dispersing step is preferably performed by a wet method. In addition, as a disperser used in this wet method, any of an open type and a closed type can be used. For example, a ball mill, a stirring mill, a jet mill, a vibration mill, an attritor, a high speed mill, a hammer mill, etc. Preferably used. Examples of the ball mill include a rolling mill, a vibration mill, and a planetary mill. Examples of the stirring mill include a tower mill, a stirring tank mill, a flow pipe mill, and a tubular mill.
Moreover, you may add hydrophilic or hydrophobic polymer | macromolecule, surfactant, antiseptic | preservative, a stabilizer, an antifoamer, a leveling agent etc. as needed.
以上のような構成の塗料によれば、本発明の目的とする排ガス浄化フィルタに好適に用いられる、貴金属とＳｉＣ微粒子を成分とし、均質性に優れた多孔質膜を容易に形成することができる。隔壁を構成する粒子の表面に触媒が直接担持されるこの触媒塗料は、塗布するだけで隔壁を構成する粒子の表面に触媒が直接担持することができるので、対象物の形状等の制約を受けることなく、その隔壁を構成する粒子の表面に触媒を直接担持が容易にできる。 According to the coating material having the above-described configuration, it is possible to easily form a porous film excellent in homogeneity using precious metal and SiC fine particles as components, which are preferably used in the exhaust gas purification filter of the present invention. . This catalyst coating, in which the catalyst is directly supported on the surface of the particles constituting the partition walls, can be directly supported on the surface of the particles constituting the partition walls simply by coating, and thus is subject to restrictions such as the shape of the object. The catalyst can be easily supported directly on the surface of the particles constituting the partition wall.
以上、添付図面を参照しながら本発明に係る好適な実施の形態例について説明したが、本発明は係る例に限定されないことは言うまでもない。上述した例において示した各構成部材の諸形状や組み合わせ等は一例であって、本発明の主旨から逸脱しない範囲において設計要求等に基づき種々変更可能である。 The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.
以下、実施例及び比較例により本発明を具体的に説明するが、本発明はこれらの実施例によって限定されるものではない。 EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited by these Examples.
［各測定・評価方法］
始めに、本実施例及び比較例の内燃機関の排ガス浄化装置の評価方法を示す。
（１）塗料中の触媒粒子の平均分散粒子径
塗料中の「触媒粒子」又は「触媒粒子前駆体に含まれる炭化ケイ素粒子」の平均分散粒子径は、レーザー回折／散乱式粒度分布測定装置ＬＡ−９２０（堀場製作所社製）を用い、レーザー回折／散乱法により測定した。
[Each measurement and evaluation method]
First, an evaluation method of the exhaust gas purifying apparatus for the internal combustion engine of the present embodiment and the comparative example will be described.
(1) Average dispersion particle diameter of catalyst particles in paint The average dispersion particle diameter of “catalyst particles” or “silicon carbide particles contained in the catalyst particle precursor” in the paint is determined by the laser diffraction / scattering particle size distribution measuring apparatus LA. -920 (manufactured by Horiba Seisakusho) was used for measurement by laser diffraction / scattering method.
（２）塗料の粘度
塗料の粘度は、Ｂ型粘度計ＢＬＩＩ及びＢＨＩＩ（東機産業社製）を用いて測定した。
(2) Viscosity of paint The viscosity of the paint was measured using a B-type viscometer BLII and BHII (manufactured by Toki Sangyo Co., Ltd.).
（３）触媒粒子の酸化物層厚み及び貴金属粒子の平均一次粒子径
触媒粒子を備えた排ガス浄化装置より多孔質基材を切り出し、電界放出型透過電子顕微鏡（ＦＥ−ＴＥＭ）ＪＥＭ−２１００Ｆ（日本電子社製）により観察することにより、貴金属粒子の担持状態を評価した。
また、触媒粒子の酸化膜厚み及び貴金属粒子の平均一次粒子径は、同様にして得られた観察画像中から無作為に選択した５０個を測定し、平均値を算出した。
(3) Oxide layer thickness of catalyst particles and average primary particle diameter of noble metal particles A porous substrate was cut out from an exhaust gas purifying apparatus equipped with catalyst particles, and a field emission transmission electron microscope (FE-TEM) JEM-2100F (Japan) The state of supporting the noble metal particles was evaluated by observing with an electronic company).
In addition, the oxide film thickness of the catalyst particles and the average primary particle diameter of the noble metal particles were determined by measuring 50 particles randomly selected from observation images obtained in the same manner, and calculating the average value.
（４）触媒粒子の有効割り合い
触媒粒子が排ガスと直接接する割り合いは、比表面積により評価した。
測定は自動比表面積測定装置ＢＥＬＳＯＲＰ ＭＩＮＩ（日本ベル社製）を用いて、触媒粒子単体、多孔質基材単体及び触媒粒子を担持した多孔質基材の比表面積を測定した。得られた結果より、基材に担持した触媒粒子の有効比表面積を算出した。
(4) Effective proportion of catalyst particles The proportion of catalyst particles in direct contact with exhaust gas was evaluated by specific surface area.
The measurement was carried out using an automatic specific surface area measuring apparatus BELSORP MINI (manufactured by Nippon Bell Co., Ltd.) to measure the specific surface area of the catalyst particles alone, the porous substrate alone and the porous substrate carrying the catalyst particles. From the obtained results, the effective specific surface area of the catalyst particles supported on the substrate was calculated.
（５）排ガス浄化装置の初期圧力損失
触媒粒子を担持した多孔質基材（３４．５×３４．５×Ｌ５０ｍｍ）について、初期圧損評価装置（東京窯業社製）を用いて初期圧力損失を評価した。差圧測定時のガス流量は、１４．７Ｌ／秒とした。
(5) Initial pressure loss of exhaust gas purification device For the porous base material (34.5 × 34.5 × L50mm) supporting catalyst particles, the initial pressure loss is evaluated using an initial pressure loss evaluation device (manufactured by Tokyo Ceramic Industry Co., Ltd.). did. The gas flow rate during differential pressure measurement was 14.7 L / sec.
（６）排ガス浄化装置のＰＭ捕集後の圧力損失
初期圧力損失を測定した触媒粒子を担持した多孔質基材に、２リッタークラスのガソリン直噴エンジンからの排ガスを１５分間通過させた後、初期圧力損失と同様の方法を用いて、ＰＭ捕集後の圧力損失測定を測定した。
(6) Pressure loss after PM collection by exhaust gas purification device After passing exhaust gas from a 2-liter class gasoline direct injection engine for 15 minutes through a porous substrate carrying catalyst particles whose initial pressure loss was measured, Using the same method as the initial pressure loss, the pressure loss measurement after PM collection was measured.
（７）排ガス浄化装置の浄化性能
２リッタークラスのガソリン直噴エンジンを用いたベンチ試験より、排ガス浄化装置を通過して排出されるＣＯの平均濃度及びＣＯ２の平均濃度を測定した。ＣＯの平均濃度を［ＣＯ］、ＣＯ２の平均濃度を［ＣＯ２］としたとき、下記式（１）より排ガス浄化性能を求め、性能を評価した。
排ガス浄化性能（％）＝{［ＣＯ２］／（［ＣＯ］＋［ＣＯ２］）}×１００ …（１）
(7) Purification performance of exhaust gas purification device The average concentration of CO and the average concentration of CO 2 discharged through the exhaust gas purification device were measured from a bench test using a 2-liter class gasoline direct injection engine. The average concentration of CO [CO], when the average concentration of CO 2 and [CO 2], determine the exhaust gas purification performance by the following formula (1) to evaluate the performance.
Exhaust gas purification performance (%) = {[CO 2 ] / ([CO] + [CO 2 ])} × 100 (1)
（８）排ガス浄化装置のＰＭ流出量
２リッタークラスのガソリン直噴エンジンの排ガスを排ガス浄化装置に通過させ、排ガス浄化装置後方（排気側）から採取した排ガス中の粒子個数濃度及び粒子径分布を、粒子カウンター及び光学スモークメータを用いて、１５分間連続的に測定した。ＰＭ粒子径分布に対して、最も高い粒子個数濃度（個／ｃｍ３）をＰＭ排出量とした。
(8) PM outflow of exhaust gas purifier The exhaust gas from a 2-liter gasoline direct injection engine is passed through the exhaust gas purifier, and the particle number concentration and particle size distribution in the exhaust gas collected from the rear (exhaust side) of the exhaust gas purifier , Measured continuously for 15 minutes using a particle counter and optical smoke meter. With respect to the PM particle size distribution, the highest particle number concentration (number / cm 3 ) was defined as the PM emission amount.
［実施例１］
平均一次粒子径が０．０３５μｍの炭化ケイ素粒子を３２０ｇ、ポリカルボン酸系分散剤２３ｇ及び水５５００ｇをボールミルで２４時間混合し、固形分が５．５質量％の炭化ケイ素粒子分散液を得た。作成した炭化ケイ素粒子分散液５８４３ｇに、ジアンミンジニトロ白金６０ｇを添加し、ボールミルで２４時間混合した。次いで、メチルセルロースＡ（２％水溶液の粘度が１００ｍＰａ・ｓ）を１０質量％含む水溶液１５００ｇ、水５０００ｇ、ＰＶＡ２５ｇ及び平均一次粒子径１０μｍのＰＭＭＡを３２０ｇを加えてボールミルでさらに２時間混合した。
さらに、得られた分散液をアンモニア水でｐＨを９．０に調整し、実施例１の塗料を得た。
[Example 1]
320 g of silicon carbide particles having an average primary particle size of 0.035 μm, 23 g of a polycarboxylic acid-based dispersant and 5500 g of water were mixed for 24 hours with a ball mill to obtain a silicon carbide particle dispersion having a solid content of 5.5% by mass. . To 5843 g of the prepared silicon carbide particle dispersion, 60 g of diamine dinitroplatinum was added and mixed for 24 hours with a ball mill. Next, 1500 g of an aqueous solution containing 10% by mass of methylcellulose A (2% aqueous solution having a viscosity of 100 mPa · s), 5000 g of water, 25 g of PVA, and 320 g of PMMA having an average primary particle size of 10 μm were added and further mixed for 2 hours by a ball mill.
Further, the pH of the obtained dispersion was adjusted to 9.0 with aqueous ammonia to obtain the coating material of Example 1.
多孔質基材として、ウォールフロー型のイビデン製ＳｉＣフィルター（φ１インチ×Ｌ２インチ・３００Ｃｅｌｌ／１０ｍｉｌ，１１μｍ、４２％）を選択した。この多孔質基材を、塗料中に１ｍｍ／秒で浸漬させ、５分間保持した後、０．５ｍｍ／秒で引き上げ、多孔質基材の隔壁の表面及び気孔内表面に実施例１の塗料を保持させた。
次いで、大気中１００℃で１０時間熱処理して溶媒を除去するとともに、炭化ケイ素粒子、ジアンミンジニトロ白金及び塗料中のその他の各成分を多孔質基材の隔壁の表面及び気孔内表面に保持させた。
A wall flow type Ibiden SiC filter (φ1 inch × L2 inch, 300 Cell / 10 mil, 11 μm, 42%) was selected as the porous substrate. The porous substrate was immersed in the coating material at 1 mm / second, held for 5 minutes, then pulled up at 0.5 mm / second, and the coating material of Example 1 was applied to the partition wall surface and the pore inner surface of the porous substrate. Held.
Next, the solvent was removed by heat treatment at 100 ° C. for 10 hours in the atmosphere, and the silicon carbide particles, diammine dinitroplatinum and other components in the paint were held on the partition wall surface and the pore inner surface of the porous substrate. .
次いで、アルゴン雰囲気中６５０℃で２４時間熱処理し、バインダー等として添加したメチルセルロースＡ及びＰＶＡ、並びに造孔材であるＰＭＭＡを熱分解して除去した。 Next, heat treatment was performed at 650 ° C. for 24 hours in an argon atmosphere, and methylcellulose A and PVA added as binders and PMMA as a pore former were removed by thermal decomposition.
次いで、アルゴン雰囲気中１０００℃で１時間熱処理し、ジアンミンジニトロ白金を熱分解して白金微粒子を形成し、この白金微粒子を炭化ケイ素粒子表面に担持するとともに、炭化ケイ素粒子を多孔質基材に担持させた。
次いで、大気中７００℃で３０時間熱処理し、炭化ケイ素粒子表面に酸化膜物層を形成することで、実施例１の内燃機関の排ガス浄化装置を作製した。
Next, heat treatment is performed at 1000 ° C. for 1 hour in an argon atmosphere to thermally decompose diamine dinitroplatinum to form platinum fine particles. The platinum fine particles are supported on the surface of the silicon carbide particles, and the silicon carbide particles are supported on the porous substrate. I let you.
Subsequently, the exhaust gas purification apparatus of the internal combustion engine of Example 1 was produced by heat-processing at 700 degreeC in air | atmosphere for 30 hours, and forming an oxide film layer on the silicon carbide particle surface.
得られた、実施例１の内燃機関の排ガス浄化装置における触媒粒子は、炭化ケイ素粒子表面に平均一次粒子径が４．３ｎｍの白金微粒子が担持され，厚さ５ｎｍの酸化物層が形成されており、この酸化物層により白金微粒子が覆われていた。また、白金の担持量は０．５ｇ／Ｌであった。
これらの排ガス浄化装置の評価結果をまとめて、表１，２に示す。
The obtained catalyst particles in the exhaust gas purifying apparatus of the internal combustion engine of Example 1 were obtained by carrying platinum fine particles having an average primary particle size of 4.3 nm on the surface of the silicon carbide particles and forming an oxide layer having a thickness of 5 nm. In addition, platinum fine particles were covered with this oxide layer. The supported amount of platinum was 0.5 g / L.
The evaluation results of these exhaust gas purification apparatuses are summarized in Tables 1 and 2.
［実施例２］
炭化ケイ素粒子として、平均一次粒子径が０．８μｍの炭化ケイ素粒子を用いたこと以外は、実施例１と同様の方法により、実施例２の内燃機関の排ガス浄化装置を得た。
[Example 2]
An exhaust gas purification apparatus for an internal combustion engine of Example 2 was obtained by the same method as Example 1 except that silicon carbide particles having an average primary particle size of 0.8 μm were used as the silicon carbide particles.
得られた、実施例２の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for an internal combustion engine of Example 2 was evaluated in the same manner as the exhaust gas purification apparatus for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［実施例３］
炭化ケイ素粒子として、平均一次粒子径が０．０１μｍの炭化ケイ素粒子を用いたこと以外は、実施例１と同様の方法により、実施例３の内燃機関の排ガス浄化装置を得た。
[Example 3]
An exhaust gas purification apparatus for an internal combustion engine of Example 3 was obtained by the same method as Example 1 except that silicon carbide particles having an average primary particle diameter of 0.01 μm were used as the silicon carbide particles.
得られた、実施例３の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for an internal combustion engine of Example 3 was evaluated in the same manner as the exhaust gas purification apparatus for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［実施例４］
塗料のｐＨを１２．０に調整したこと以外は、実施例１と同様の方法により、実施例４の内燃機関の排ガス浄化装置を得た。
[Example 4]
An exhaust gas purification apparatus for an internal combustion engine of Example 4 was obtained in the same manner as in Example 1 except that the pH of the paint was adjusted to 12.0.
得られた、実施例４の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for an internal combustion engine of Example 4 was evaluated in the same manner as the exhaust gas purification apparatus for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［実施例５］
塗料のｐＨを７．０に調整したこと以外は、実施例１と同様の方法により、実施例５の内燃機関の排ガス浄化装置を得た。
[Example 5]
An exhaust gas purification apparatus for an internal combustion engine of Example 5 was obtained in the same manner as in Example 1 except that the pH of the paint was adjusted to 7.0.
得られた、実施例５の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification device for an internal combustion engine of Example 5 was evaluated in the same manner as the exhaust gas purification device for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［実施例６］
アルゴン雰囲気中１０００℃で１時間の熱処理に替えて、アルゴン雰囲気中８００℃で１時間の熱処理としたこと以外は、実施例１と同様の方法により、実施例６の内燃機関の排ガス浄化装置を得た。
[Example 6]
The exhaust gas purifying apparatus for an internal combustion engine of Example 6 was changed in the same manner as in Example 1 except that the heat treatment was performed at 800 ° C. for 1 hour in an argon atmosphere instead of the heat treatment for 1 hour at 1000 ° C. in an argon atmosphere. Obtained.
得られた、実施例６の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for an internal combustion engine of Example 6 was evaluated in the same manner as the exhaust gas purification apparatus for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［実施例７］
アルゴン雰囲気中１０００℃で１時間の熱処理に替えて、アルゴン雰囲気中８００℃で１時間の熱処理としたこと、及び大気中７００℃で３０時間の熱処理に替えて、大気中１０００℃で３０時間熱処理したこと以外は、実施例２と同様の方法により、実施例７の内燃機関の排ガス浄化装置を得た。
[Example 7]
Changed to heat treatment for 1 hour at 800 ° C. in argon atmosphere instead of heat treatment for 1 hour at 1000 ° C. in argon atmosphere, and changed to heat treatment for 30 hours at 700 ° C. in air for 30 hours at 1000 ° C. in air Except for this, an exhaust gas purification apparatus for an internal combustion engine of Example 7 was obtained in the same manner as in Example 2.
得られた、実施例７の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for an internal combustion engine of Example 7 was evaluated in the same manner as the exhaust gas purification apparatus for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［実施例８］
アルゴン雰囲気中１０００℃で１時間の熱処理に替えて、アルゴン雰囲気中８００℃で１時間の熱処理としたこと、及び大気中７００℃で３０時間の熱処理に替えて、大気中１０００℃で３０時間熱処理したこと以外は、実施例２と同様の方法により、実施例８の内燃機関の排ガス浄化装置を得た。
[Example 8]
Changed to heat treatment for 1 hour at 800 ° C. in argon atmosphere instead of heat treatment for 1 hour at 1000 ° C. in argon atmosphere, and changed to heat treatment for 30 hours at 700 ° C. in air for 30 hours at 1000 ° C. in air Except for this, an exhaust gas purification apparatus for an internal combustion engine of Example 8 was obtained in the same manner as in Example 2.
得られた、実施例８の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for an internal combustion engine of Example 8 was evaluated in the same manner as the exhaust gas purification apparatus for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［比較例１］
各実施例で多孔質基材として用いた、ウォールフロー型のイビデン製ＳｉＣフィルター（φ１インチ×Ｌ２インチ・３００Ｃｅｌｌ／１０ｍｉｌ，１１μｍ、４２％）を、そのまま（触媒粒子を担持させることなく）比較例１の内燃機関の排ガス浄化装置とした。
[Comparative Example 1]
A wall flow type Ibiden SiC filter (φ1 inch × L2 inch, 300 Cell / 10 mil, 11 μm, 42%) used as a porous base material in each example is used as it is (without supporting catalyst particles). The exhaust gas purifying apparatus of No. 1 was used.
得られた、比較例１の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification device for the internal combustion engine of Comparative Example 1 was evaluated in the same manner as the exhaust gas purification device for the internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［比較例２］
炭化ケイ素粒子として、平均一次粒子径が１．２μｍの炭化ケイ素粒子を用いたこと以外は、実施例１と同様の方法により、比較例２の内燃機関の排ガス浄化装置を得た。
[Comparative Example 2]
An exhaust gas purification device for an internal combustion engine of Comparative Example 2 was obtained by the same method as Example 1 except that silicon carbide particles having an average primary particle size of 1.2 μm were used as the silicon carbide particles.
得られた、比較例２の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for the internal combustion engine of Comparative Example 2 was evaluated in the same manner as the exhaust gas purification apparatus for the internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［比較例３］
炭化ケイ素粒子として、平均一次粒子径が０．００３μｍの炭化ケイ素粒子を用いたこと以外は、実施例１と同様の方法により、比較例３の内燃機関の排ガス浄化装置を得た。
[Comparative Example 3]
An exhaust gas purification device for an internal combustion engine of Comparative Example 3 was obtained by the same method as Example 1 except that silicon carbide particles having an average primary particle size of 0.003 μm were used as the silicon carbide particles.
得られた、比較例３の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus for the internal combustion engine of Comparative Example 3 was evaluated in the same manner as the exhaust gas purification apparatus for the internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［比較例４］
塗料のｐＨを６．０に調整したこと以外は、実施例１と同様の方法により、比較例４の内燃機関の排ガス浄化装置を得た。
[Comparative Example 4]
An exhaust gas purification apparatus for an internal combustion engine of Comparative Example 4 was obtained in the same manner as in Example 1 except that the pH of the paint was adjusted to 6.0.
得られた、比較例４の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus of the internal combustion engine of Comparative Example 4 was evaluated in the same manner as the exhaust gas purification apparatus of the internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［比較例５］
塗料のｐＨを１３．０に調整したこと以外は、実施例１と同様の方法により、比較例５の内燃機関の排ガス浄化装置を得た。
[Comparative Example 5]
An exhaust gas purification apparatus for an internal combustion engine of Comparative Example 5 was obtained in the same manner as in Example 1 except that the pH of the paint was adjusted to 13.0.
得られた、比較例５の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification device for an internal combustion engine of Comparative Example 5 was evaluated in the same manner as the exhaust gas purification device for an internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［比較例６］
アルゴン雰囲気中１０００℃で１時間の熱処理に替えて、アルゴン雰囲気中１６００℃で１時間の熱処理としたこと以外は、実施例１と同様の方法により、比較例６の内燃機関の排ガス浄化装置を得た。
[Comparative Example 6]
The internal combustion engine exhaust gas purification apparatus of Comparative Example 6 was manufactured in the same manner as in Example 1 except that the heat treatment was performed at 1000 ° C. for 1 hour in an argon atmosphere and heat treatment was performed for 1 hour at 1600 ° C. in an argon atmosphere. Obtained.
得られた、比較例６の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification device for the internal combustion engine of Comparative Example 6 was evaluated in the same manner as the exhaust gas purification device for the internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
［比較例７］
炭化ケイ素粒子分散液作製時におけるボールミルでの２４時間混合及び炭化ケイ素粒子分散液にジアンミンジニトロ白金を添加後のボールミルでの２４時間混合に替えて、それぞれ、サンドミルを用いた３時間混合としたこと、アルゴン雰囲気中１０００℃で１時間の熱処理に替えて、アルゴン雰囲気中７００℃で１時間の熱処理としたこと並びに大気中７００℃で３０時間の熱処理に替えて、大気中８００℃で３０時間熱処理したこと以外は、実施例２と同様の方法により、比較例７の内燃機関の排ガス浄化装置を得た。
[Comparative Example 7]
Instead of mixing for 24 hours in a ball mill at the time of preparing the silicon carbide particle dispersion and mixing for 24 hours in the ball mill after adding diamine dinitroplatinum to the silicon carbide particle dispersion, mixing was performed for 3 hours using a sand mill, respectively. The heat treatment for 1 hour at 1000 ° C. in an argon atmosphere was replaced with the heat treatment for 1 hour at 700 ° C. in the argon atmosphere, and the heat treatment at 800 ° C. in the air for 30 hours instead of the heat treatment for 30 hours at 700 ° C. in the air. Except that, an exhaust gas purifying apparatus for an internal combustion engine of Comparative Example 7 was obtained in the same manner as in Example 2.
得られた、比較例７の内燃機関の排ガス浄化装置を、実施例１の内燃機関の排ガス浄化装置と同様に評価した。評価結果をまとめて、表１，２に示す。 The obtained exhaust gas purification apparatus of the internal combustion engine of Comparative Example 7 was evaluated in the same manner as the exhaust gas purification apparatus of the internal combustion engine of Example 1. The evaluation results are summarized and shown in Tables 1 and 2.
各実施例の内燃機関の排ガス浄化装置では、炭化ケイ素粒子の表面にナノメートルサイズの貴金属微粒子が担持され、炭化ケイ素粒子の表面には酸化物層が形成されるとともに、この酸化物層が貴金属微粒子を覆っていた。
さらに、各実施例の内燃機関の排ガス浄化装置では、ＣＯの排出が非常に少なく、またＰＭの排出量も非常に少なかった。この結果から、本実施例の内燃機関の排ガス浄化装置は、ＰＭ浄化性能が高く、ほとんどのＰＭをＣＯ２として排出していると判断できる。これは排ガス浄化装置に担持した触媒粒子と排ガスの接触面積が非常に高いことを意味している。
また、各実施例の内燃機関の排ガス浄化装置では、ＰＭ捕集後の圧力損失及びＰＭ流出量が少なかった。これは、ＰＭ浄化性能が高いこと、またガソリンエンジンの排気温度が高いことから、エンジンから排出されたＰＭは、触媒粒子と接触するとほぼ同時に酸化してＣＯ２となり消失するためと考えられる。
In the exhaust gas purification apparatus for an internal combustion engine of each embodiment, nanometer-sized noble metal fine particles are supported on the surface of the silicon carbide particles, and an oxide layer is formed on the surface of the silicon carbide particles. It covered fine particles.
Furthermore, in the exhaust gas purifying apparatus for the internal combustion engine of each example, CO emissions were very small and PM emissions were also very small. From this result, it can be determined that the exhaust gas purification apparatus for an internal combustion engine of the present embodiment has high PM purification performance and discharges most of the PM as CO 2 . This means that the contact area between the catalyst particles carried on the exhaust gas purification device and the exhaust gas is very high.
Moreover, in the exhaust gas purification apparatus of the internal combustion engine of each Example, there was little pressure loss and PM outflow after PM collection. This is presumably because the PM purification performance is high and the exhaust temperature of the gasoline engine is high, so that PM discharged from the engine is oxidized almost simultaneously with CO 2 and disappears when it comes into contact with the catalyst particles.
一方、比較例２においては、炭化ケイ素粒子の平均一次粒子径が大きいため、多孔質基材内に触媒粒子を均一に配置することができず、このため触媒粒子の有効割合が低かった。
比較例３においては、炭化ケイ素粒子の平均一次粒子径が小さいために、炭化ケイ素粒子同士が塗料内で凝集を起こしていたこと、また塗料の粘度が大きく触媒粒子担持量が過大になっていたことから、触媒粒子の有効割合が低かった。また、塗料の粘度が大きく触媒粒子担持量が過大なため、圧力損失が増大し、排ガスの流れが不均一となり、十分な排ガス浄化性能を発現しなかった。
比較例４においては、塗料のｐＨが低いために、炭化ケイ素粒子が塗料内で凝集を起こしていたこと、また塗料の粘度が大きく触媒粒子担持量が過大になっていたことから、触媒粒子の有効割合が低かった。また、塗料の粘度が大きく触媒粒子担持量が過大なため、圧力損失が増大し、排ガスの流れが不均一となり、十分な排ガス浄化性能を発現しなかった。
On the other hand, in Comparative Example 2, since the average primary particle diameter of the silicon carbide particles was large, the catalyst particles could not be uniformly arranged in the porous substrate, and therefore the effective ratio of the catalyst particles was low.
In Comparative Example 3, since the average primary particle diameter of the silicon carbide particles was small, the silicon carbide particles were agglomerated in the paint, and the viscosity of the paint was large and the amount of catalyst particles supported was excessive. Therefore, the effective ratio of catalyst particles was low. Further, since the viscosity of the paint was large and the amount of catalyst particles supported was excessive, the pressure loss increased, the exhaust gas flow became non-uniform, and sufficient exhaust gas purification performance was not exhibited.
In Comparative Example 4, since the pH of the paint was low, the silicon carbide particles were aggregated in the paint, and the viscosity of the paint was large and the amount of catalyst particles supported was excessive. The effective rate was low. Further, since the viscosity of the paint was large and the amount of catalyst particles supported was excessive, the pressure loss increased, the exhaust gas flow became non-uniform, and sufficient exhaust gas purification performance was not exhibited.
比較例５においては、塗料のｐＨが高いために安定した塗料が得られず、排ガス浄化装置としての評価ができなかった。
比較例６においては、アルゴン雰囲気中での加熱温度が高いために、白金粒子の粒子径が過大となっていた。このため、白金粒子が酸化物層に十分覆われていなかった。このため、十分な排ガス浄化性能が得られなかった。
比較例７においては、ボールミルに比べて解砕力の強いサンドミルを用いたことから，炭化ケイ素粒子の平均分散粒子径が小さく、このため触媒粒子の平均粒子径が小さくなりすぎ、触媒粒子の有効割合が低かった。また、触媒粒子上の貴金属微粒子の平均一次粒子径も小さいために、十分な排ガス浄化性能が得られなかった。
In Comparative Example 5, since the pH of the paint was high, a stable paint could not be obtained, and the exhaust gas purification device could not be evaluated.
In Comparative Example 6, since the heating temperature in the argon atmosphere was high, the particle diameter of the platinum particles was excessive. For this reason, the platinum particles were not sufficiently covered with the oxide layer. For this reason, sufficient exhaust gas purification performance was not obtained.
In Comparative Example 7, since a sand mill having a higher crushing force than that of the ball mill was used, the average dispersed particle size of the silicon carbide particles was small, so that the average particle size of the catalyst particles was too small, and the effective ratio of the catalyst particles was It was low. Moreover, since the average primary particle diameter of the noble metal fine particles on the catalyst particles is small, sufficient exhaust gas purification performance cannot be obtained.
以上の結果から、本発明が有用であることが確かめられた。 From the above results, it was confirmed that the present invention is useful.
１０，２０…排ガス浄化装置、１１，２１…隔壁、１２，２２…ガス流路、１２Ａ，２２Ａ…流入側ガス流路、１２Ｂ，２２Ｂ…排出側ガス流路、３０…ＰＭ（粒子状物質）、α、γ…端面、Ｇ…排ガス、Ｃ…浄化ガス
DESCRIPTION OF
Claims (5)
セラミックス製の多孔質基材と、
前記多孔質基材の表面及び気孔内表面に担持された触媒粒子とを有してなり、
前記触媒粒子は、前記多孔質基材の表面及び気孔内表面に直接担持されるとともに、前記触媒粒子の７５％以上が排ガスと直接接する状態で保持されており、
前記触媒粒子は、炭化ケイ素粒子の表面に貴金属粒子が担持されてなり、前記貴金属粒子が酸化物層により覆われた状態であることを特徴とする内燃機関の排ガス浄化装置。 An exhaust gas purification device for an internal combustion engine,
A ceramic porous substrate;
Comprising catalyst particles carried on the surface of the porous substrate and the inner surface of the pores,
The catalyst particles are directly supported on the surface of the porous substrate and the inner surface of the pores, and 75% or more of the catalyst particles are held in direct contact with the exhaust gas,
The exhaust gas purifying apparatus for an internal combustion engine, wherein the catalyst particles are formed by supporting noble metal particles on the surface of silicon carbide particles, and the noble metal particles are covered with an oxide layer.
貴金属粒子を炭化ケイ素粒子に担持させ貴金属粒子担持炭化ケイ素粒子を作製する「貴金属粒子担持工程」、
前記貴金属粒子担持炭化ケイ素粒子の表面に酸化物層を形成し、前記貴金属粒子が前記酸化物層により覆われた状態で保持された触媒粒子を形成する「触媒粒子形成工程」を含み、
さらに、前記貴金属粒子を担持した炭化ケイ素粒子又は触媒粒子を前記多孔質基材の表面及び気孔内表面に保持させる際に造孔材を使用することを特徴とする内燃機関の排ガス浄化装置の製造方法。 A method for manufacturing an exhaust gas purification apparatus for an internal combustion engine according to any one of claims 1 to 3,
“Precious metal particle supporting step” for producing precious metal particle-supported silicon carbide particles by supporting precious metal particles on silicon carbide particles,
Including a "catalyst particle forming step" in which an oxide layer is formed on the surface of the noble metal particle-supported silicon carbide particles, and the noble metal particles are formed to be retained in a state covered with the oxide layer.
Further, a manufacturing method of an exhaust gas purification apparatus for an internal combustion engine, wherein a pore former is used when the silicon carbide particles or catalyst particles supporting the noble metal particles are held on the surface of the porous substrate and the inner surface of the pores. Method.
触媒粒子又は触媒粒子前駆体、
造孔材、
並びに分散媒を含有してなり、
前記塗料が触媒粒子を含む場合、前記触媒粒子の平均分散粒子径が０．１μｍ以上かつ４μｍ以下であり、
前記塗料が触媒粒子前駆体を含む場合、前記触媒粒子前駆体に含まれる炭化ケイ素粒子の平均分散粒子径は０．１μｍ以上かつ４μｍ以下であることを特徴とする排ガス浄化装置作製用塗料。 A paint for producing an exhaust gas purification device for an internal combustion engine, at least,
Catalyst particles or catalyst particle precursors,
Pore former,
As well as a dispersion medium,
When the paint contains catalyst particles, the average dispersed particle size of the catalyst particles is 0.1 μm or more and 4 μm or less,
When the paint contains a catalyst particle precursor, the average dispersed particle size of silicon carbide particles contained in the catalyst particle precursor is 0.1 μm or more and 4 μm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2015070154A JP2015199066A (en) | 2014-03-31 | 2015-03-30 | Exhaust gas purification device for internal combustion engine, production method of the same and paint for producing exhaust gas purification device |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014074287 | 2014-03-31 | ||
| JP2014074287 | 2014-03-31 | ||
| JP2015070154A JP2015199066A (en) | 2014-03-31 | 2015-03-30 | Exhaust gas purification device for internal combustion engine, production method of the same and paint for producing exhaust gas purification device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2015199066A true JP2015199066A (en) | 2015-11-12 |
Family
ID=54550887
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2015070154A Pending JP2015199066A (en) | 2014-03-31 | 2015-03-30 | Exhaust gas purification device for internal combustion engine, production method of the same and paint for producing exhaust gas purification device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2015199066A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020044516A (en) * | 2018-09-20 | 2020-03-26 | トヨタ自動車株式会社 | Cluster-supported catalyst and method for producing the same |
| WO2020100830A1 (en) | 2018-11-12 | 2020-05-22 | ユミコア日本触媒株式会社 | Diesel engine exhaust gas purification catalyst, production method therefor, and exhaust gas purification method using same |
| WO2020137201A1 (en) | 2018-12-28 | 2020-07-02 | ユミコア日本触媒株式会社 | Catalyst for exhaust gas oxidation, method for producing same, and exhaust gas oxidation method using same |
| CN112955257A (en) * | 2018-11-12 | 2021-06-11 | 优美科触媒日本有限公司 | Catalyst for purifying exhaust gas of gasoline engine, method for producing same, and method for purifying exhaust gas using same |
| CN113164945A (en) * | 2019-08-09 | 2021-07-23 | 三井金属矿业株式会社 | Exhaust gas purifying catalyst and method for producing same |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04149016A (en) * | 1990-10-11 | 1992-05-22 | Mitsui Toatsu Chem Inc | Refining method for sic powder |
| JPH06183717A (en) * | 1992-12-17 | 1994-07-05 | Hitachi Powdered Metals Co Ltd | Production of silicon carbide powder |
| WO2011052676A1 (en) * | 2009-10-30 | 2011-05-05 | 住友大阪セメント株式会社 | Exhaust cleaner for internal combustion engine |
| JP2011093756A (en) * | 2009-10-30 | 2011-05-12 | Sumitomo Osaka Cement Co Ltd | Noble metal supporting silicon carbide particle and method for producing the same, catalyst containing the same and method for producing the same |
| JP2012246220A (en) * | 2012-09-07 | 2012-12-13 | Sumitomo Osaka Cement Co Ltd | Method for producing silicon carbide nanoparticle dispersion, and silicon carbide nanoparticle dispersion and silicon carbide nanoparticle film |
| JP2013063420A (en) * | 2011-08-26 | 2013-04-11 | Sumitomo Osaka Cement Co Ltd | Exhaust gas purification filter |
| JP2013063421A (en) * | 2011-08-26 | 2013-04-11 | Sumitomo Osaka Cement Co Ltd | Exhaust purification catalyst and exhaust gas purifier of internal combustion engine |
| JP2015009213A (en) * | 2013-06-28 | 2015-01-19 | 住友大阪セメント株式会社 | Exhaust gas purification catalyst and exhaust gas purification device for internal combustion engine |
-
2015
- 2015-03-30 JP JP2015070154A patent/JP2015199066A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04149016A (en) * | 1990-10-11 | 1992-05-22 | Mitsui Toatsu Chem Inc | Refining method for sic powder |
| JPH06183717A (en) * | 1992-12-17 | 1994-07-05 | Hitachi Powdered Metals Co Ltd | Production of silicon carbide powder |
| WO2011052676A1 (en) * | 2009-10-30 | 2011-05-05 | 住友大阪セメント株式会社 | Exhaust cleaner for internal combustion engine |
| JP2011093756A (en) * | 2009-10-30 | 2011-05-12 | Sumitomo Osaka Cement Co Ltd | Noble metal supporting silicon carbide particle and method for producing the same, catalyst containing the same and method for producing the same |
| JP2013063420A (en) * | 2011-08-26 | 2013-04-11 | Sumitomo Osaka Cement Co Ltd | Exhaust gas purification filter |
| JP2013063421A (en) * | 2011-08-26 | 2013-04-11 | Sumitomo Osaka Cement Co Ltd | Exhaust purification catalyst and exhaust gas purifier of internal combustion engine |
| JP2012246220A (en) * | 2012-09-07 | 2012-12-13 | Sumitomo Osaka Cement Co Ltd | Method for producing silicon carbide nanoparticle dispersion, and silicon carbide nanoparticle dispersion and silicon carbide nanoparticle film |
| JP2015009213A (en) * | 2013-06-28 | 2015-01-19 | 住友大阪セメント株式会社 | Exhaust gas purification catalyst and exhaust gas purification device for internal combustion engine |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2020044516A (en) * | 2018-09-20 | 2020-03-26 | トヨタ自動車株式会社 | Cluster-supported catalyst and method for producing the same |
| JP7125229B2 (en) | 2018-09-20 | 2022-08-24 | トヨタ自動車株式会社 | Cluster-supported catalyst and method for producing the same |
| WO2020100830A1 (en) | 2018-11-12 | 2020-05-22 | ユミコア日本触媒株式会社 | Diesel engine exhaust gas purification catalyst, production method therefor, and exhaust gas purification method using same |
| CN112955257A (en) * | 2018-11-12 | 2021-06-11 | 优美科触媒日本有限公司 | Catalyst for purifying exhaust gas of gasoline engine, method for producing same, and method for purifying exhaust gas using same |
| US11344864B2 (en) | 2018-11-12 | 2022-05-31 | Umicore Shokubai Japan Co., Ltd. | Diesel engine exhaust gas purification catalyst, production method therefor, and exhaust gas purification method using the same |
| US11813590B2 (en) | 2018-11-12 | 2023-11-14 | Umicore Shokubai Japan Co., Ltd. | Gasoline engine exhaust gas purification catalyst, production method therefor, and exhaust gas purification method using the same |
| CN112955257B (en) * | 2018-11-12 | 2024-01-12 | 优美科触媒日本有限公司 | Catalyst for purifying exhaust gas of gasoline engine, method for producing the same, and method for purifying exhaust gas using the same |
| WO2020137201A1 (en) | 2018-12-28 | 2020-07-02 | ユミコア日本触媒株式会社 | Catalyst for exhaust gas oxidation, method for producing same, and exhaust gas oxidation method using same |
| US11691133B2 (en) | 2018-12-28 | 2023-07-04 | Umicore Shokubai Japan Co., Ltd. | Catalyst for exhaust gas oxidation, method for producing same, and exhaust gas oxidation method using same |
| CN113164945A (en) * | 2019-08-09 | 2021-07-23 | 三井金属矿业株式会社 | Exhaust gas purifying catalyst and method for producing same |
| CN113164945B (en) * | 2019-08-09 | 2022-03-18 | 三井金属矿业株式会社 | Exhaust gas purifying catalyst and method for producing same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4971166B2 (en) | Honeycomb catalyst body, precoat carrier for manufacturing honeycomb catalyst body, and method for manufacturing honeycomb catalyst body | |
| JP5690273B2 (en) | Exhaust gas purification filter | |
| JP4275406B2 (en) | Catalyst support filter | |
| EP1243335A1 (en) | Catalyst and method for preparation thereof | |
| JP5017230B2 (en) | Porous film forming paint for automobile exhaust gas purification filter, porous membrane for automobile exhaust gas purification filter, automobile exhaust gas purification filter, and automobile exhaust gas purification filter manufacturing method. | |
| JP2015199066A (en) | Exhaust gas purification device for internal combustion engine, production method of the same and paint for producing exhaust gas purification device | |
| WO2011040563A1 (en) | Exhaust gas purification filter | |
| CN108367241A (en) | The composition and its preparation and application of (PNA) system are adsorbed for passive NOX | |
| WO2018159214A1 (en) | Filter for exhaust gas cleaning and method for manufacturing same | |
| JPWO2011040554A1 (en) | Exhaust gas purification filter | |
| CN106999849A (en) | Use the triple effect catalytic converter of mixed catalytic particle | |
| JP2010269268A (en) | Honeycomb structure type filter | |
| JP2010156206A (en) | Exhaust gas purifying filter | |
| JP5920046B2 (en) | Exhaust purification catalyst, method for producing exhaust purification catalyst, and exhaust purification apparatus for internal combustion engine | |
| JP5446457B2 (en) | Porous film-forming coating material and porous film | |
| JP4412615B2 (en) | Exhaust gas purification catalyst and method for producing the same | |
| JPWO2011052676A1 (en) | Exhaust gas purification device for internal combustion engine | |
| WO2013031682A1 (en) | Exhaust purification catalyst, exhaust gas purifier of internal combustion engine, and exhaust gas purification filter | |
| JP2010269270A (en) | Honeycomb structure type filter | |
| JP5287231B2 (en) | Porous film-forming coating material and porous film | |
| JP2015009212A (en) | Exhaust gas cleaning filter | |
| JP5502885B2 (en) | Oxidation catalyst suitable for burning light oil components | |
| JP5338603B2 (en) | Porous film-forming coating material and porous film | |
| JP2013063420A (en) | Exhaust gas purification filter | |
| JP2010269269A (en) | Coating material for forming porous film and porous film |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20170807 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20181016 |
|
| RD03 | Notification of appointment of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7423 Effective date: 20181109 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20181217 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20190528 |