JPH10258232A - Catalyst for exhaust gas purification and manufacture thereof - Google Patents
Catalyst for exhaust gas purification and manufacture thereofInfo
- Publication number
- JPH10258232A JPH10258232A JP9277649A JP27764997A JPH10258232A JP H10258232 A JPH10258232 A JP H10258232A JP 9277649 A JP9277649 A JP 9277649A JP 27764997 A JP27764997 A JP 27764997A JP H10258232 A JPH10258232 A JP H10258232A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- powder
- core
- exhaust gas
- supporting layer
- 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.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 315
- 238000000746 purification Methods 0.000 title claims abstract description 84
- 238000004519 manufacturing process Methods 0.000 title claims description 13
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 58
- 230000003197 catalytic effect Effects 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 18
- 239000000843 powder Substances 0.000 claims description 171
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 72
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 67
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 44
- 239000011232 storage material Substances 0.000 claims description 44
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 41
- 239000000243 solution Substances 0.000 claims description 29
- 229910052751 metal Inorganic materials 0.000 claims description 28
- 239000002184 metal Substances 0.000 claims description 28
- 239000002131 composite material Substances 0.000 claims description 24
- 238000003860 storage Methods 0.000 claims description 21
- 239000007864 aqueous solution Substances 0.000 claims description 20
- 229910052783 alkali metal Inorganic materials 0.000 claims description 12
- 150000001340 alkali metals Chemical class 0.000 claims description 12
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 12
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
- 150000004703 alkoxides Chemical class 0.000 claims description 11
- 238000006460 hydrolysis reaction Methods 0.000 claims description 10
- 230000007062 hydrolysis Effects 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 5
- 150000003839 salts Chemical class 0.000 claims description 5
- 229910044991 metal oxide Inorganic materials 0.000 claims description 2
- 150000004706 metal oxides Chemical group 0.000 claims description 2
- 238000005245 sintering Methods 0.000 abstract description 19
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 abstract description 11
- 231100000572 poisoning Toxicity 0.000 abstract description 11
- 230000000607 poisoning effect Effects 0.000 abstract description 11
- 229910052717 sulfur Inorganic materials 0.000 abstract description 11
- 239000011593 sulfur Substances 0.000 abstract description 11
- 230000002401 inhibitory effect Effects 0.000 abstract 2
- 239000011162 core material Substances 0.000 description 165
- 239000010410 layer Substances 0.000 description 136
- 239000007789 gas Substances 0.000 description 93
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 75
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 71
- 238000012360 testing method Methods 0.000 description 48
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 description 34
- 239000000203 mixture Substances 0.000 description 27
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 26
- SMZOGRDCAXLAAR-UHFFFAOYSA-N aluminium isopropoxide Chemical compound [Al+3].CC(C)[O-].CC(C)[O-].CC(C)[O-] SMZOGRDCAXLAAR-UHFFFAOYSA-N 0.000 description 25
- 235000011056 potassium acetate Nutrition 0.000 description 17
- 239000008188 pellet Substances 0.000 description 15
- 230000000694 effects Effects 0.000 description 11
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 10
- 238000006722 reduction reaction Methods 0.000 description 10
- 239000000446 fuel Substances 0.000 description 9
- 239000002245 particle Substances 0.000 description 9
- 239000010936 titanium Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 150000002500 ions Chemical class 0.000 description 8
- 230000009467 reduction Effects 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 238000001035 drying Methods 0.000 description 7
- 229910052697 platinum Inorganic materials 0.000 description 7
- 238000003980 solgel method Methods 0.000 description 7
- 229910052782 aluminium Inorganic materials 0.000 description 6
- IXSUHTFXKKBBJP-UHFFFAOYSA-L azanide;platinum(2+);dinitrite Chemical compound [NH2-].[NH2-].[Pt+2].[O-]N=O.[O-]N=O IXSUHTFXKKBBJP-UHFFFAOYSA-L 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000010948 rhodium Substances 0.000 description 6
- 229910052815 sulfur oxide Inorganic materials 0.000 description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 5
- ITHZDDVSAWDQPZ-UHFFFAOYSA-L barium acetate Chemical compound [Ba+2].CC([O-])=O.CC([O-])=O ITHZDDVSAWDQPZ-UHFFFAOYSA-L 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- 229910017604 nitric acid Inorganic materials 0.000 description 5
- 229910052761 rare earth metal Inorganic materials 0.000 description 5
- 229910052719 titanium Inorganic materials 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 229910052723 transition metal Inorganic materials 0.000 description 4
- 150000003624 transition metals Chemical class 0.000 description 4
- 238000011144 upstream manufacturing Methods 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052788 barium Inorganic materials 0.000 description 3
- 229910052878 cordierite Inorganic materials 0.000 description 3
- 238000003795 desorption Methods 0.000 description 3
- 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 3
- 238000001879 gelation Methods 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 229910021536 Zeolite Inorganic materials 0.000 description 2
- BYFGZMCJNACEKR-UHFFFAOYSA-N aluminium(i) oxide Chemical compound [Al]O[Al] BYFGZMCJNACEKR-UHFFFAOYSA-N 0.000 description 2
- -1 barium alkoxide Chemical class 0.000 description 2
- CPUJSIVIXCTVEI-UHFFFAOYSA-N barium(2+);propan-2-olate Chemical compound [Ba+2].CC(C)[O-].CC(C)[O-] CPUJSIVIXCTVEI-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000013329 compounding Methods 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 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
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Inorganic materials [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- TXKMVPPZCYKFAC-UHFFFAOYSA-N disulfur monoxide Inorganic materials O=S=S TXKMVPPZCYKFAC-UHFFFAOYSA-N 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 229910052730 francium Inorganic materials 0.000 description 1
- KLMCZVJOEAUDNE-UHFFFAOYSA-N francium atom Chemical compound [Fr] KLMCZVJOEAUDNE-UHFFFAOYSA-N 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 1
- 231100001143 noxa Toxicity 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- NOTVAPJNGZMVSD-UHFFFAOYSA-N potassium monoxide Inorganic materials [K]O[K] NOTVAPJNGZMVSD-UHFFFAOYSA-N 0.000 description 1
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000003578 releasing effect Effects 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052701 rubidium Inorganic materials 0.000 description 1
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、自動車などの内燃
機関から排出される排ガスを浄化する排ガス浄化用触媒
とその製造方法に関し、詳しくはリーンバーンエンジン
からの排ガスを浄化するに最適な、NOx 吸蔵還元型の排
ガス浄化用触媒及びその製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying catalyst for purifying exhaust gas discharged from an internal combustion engine of an automobile or the like and a method for producing the same. More specifically, the present invention relates to a NO. The present invention relates to an occlusion reduction type exhaust gas purifying catalyst and a method for producing the same.
【０００２】[0002]
【従来の技術】従来より自動車の排ガス浄化用触媒とし
て、理論空燃比（ストイキ）において排ガス中のCO及び
HCの酸化とNOx の還元とを同時に行って浄化する三元触
媒が用いられている。このような三元触媒としては、例
えばコーディエライトなどからなる耐熱性基材にγ−ア
ルミナからなる多孔質担体層を形成し、その多孔質担体
層に白金（Pt）、ロジウム（Rh）などの触媒貴金属を担
持させたものが広く知られている。2. Description of the Related Art Conventionally, as a catalyst for purifying exhaust gas of automobiles, CO and CO in exhaust gas at a stoichiometric air-fuel ratio (stoichiometric) have been used.
A three-way catalyst that purifies by simultaneously oxidizing HC and reducing NO x is used. As such a three-way catalyst, for example, a porous carrier layer made of γ-alumina is formed on a heat-resistant substrate made of cordierite or the like, and platinum (Pt), rhodium (Rh), or the like is formed on the porous carrier layer. What carried the catalyst noble metal is widely known.
【０００３】一方、近年、地球環境保護の観点から、自
動車などの内燃機関から排出される排ガス中の二酸化炭
素（CO2 ）が問題とされ、その解決策として酸素過剰雰
囲気において希薄燃焼させるいわゆるリーンバーンが有
望視されている。このリーンバーンにおいては、燃費が
向上するために燃料の使用が低減され、その燃焼排ガス
であるCO2 の発生を抑制することができる。On the other hand, in recent years, carbon dioxide (CO 2 ) in exhaust gas discharged from internal combustion engines such as automobiles has become a problem from the viewpoint of protection of the global environment. As a solution, lean combustion in an oxygen-excess atmosphere has been proposed. Burn is promising. In this lean burn, the use of fuel is reduced in order to improve fuel efficiency, and the generation of CO 2 as combustion exhaust gas can be suppressed.
【０００４】これに対し、従来の三元触媒は、空燃比が
理論空燃比（ストイキ）において排ガス中のCO，HC，NO
x を同時に酸化・還元し浄化するものであって、リーン
バーン時の排ガスの酸素過剰雰囲気下においては、NOx
の還元除去に対して充分な浄化性能を示さない。このた
め、酸素過剰雰囲気下においてもNOx を浄化しうる触媒
及び浄化システムの開発が望まれていた。On the other hand, in the conventional three-way catalyst, when the air-fuel ratio is at the stoichiometric air-fuel ratio (stoichiometric), CO, HC, NO
It is one which simultaneously redox purifies x, in the excess oxygen atmosphere of the exhaust gas during the lean-burn, NO x
Does not show sufficient purification performance for the reduction and removal of water. Therefore, development of a catalyst and purification system has been desired can purify NO x even in an oxygen rich atmosphere.
【０００５】そこでリーンバーンにおいて、常時は酸素
過剰のリーン条件でHC，COを燃焼させるとともにNOx を
吸蔵し、一時的にストイキ〜リッチ条件とすることによ
り排ガスを還元雰囲気として、NOx を還元浄化するシス
テムが開発された。そしてこのシステムに最適な、リー
ン雰囲気でNOx を吸蔵し、ストイキ〜リッチ雰囲気で吸
蔵されたNOx を放出するNOx 吸蔵材を用いたNOx 吸蔵還
元型の排ガス浄化用触媒が開発されている。[0005] Therefore, in the lean burn, normally occludes NO x with burning HC, and CO in oxygen excess lean condition, temporarily as a reducing atmosphere gas by a stoichiometric-rich condition, reducing the NO x A purifying system was developed. The ideal for this system, occludes NO x in lean atmosphere, and the NO x storage-reduction type exhaust gas purifying catalyst using the NO x storage material that releases NO x occluded in the stoichiometric-rich atmosphere has been developed I have.
【０００６】例えば特開平5-317652号公報には、Baなど
のアルカリ土類金属とPtをアルミナなどの多孔質担体に
担持した排ガス浄化用触媒が提案されている。また特開
平 6-31139号公報には、Ｋなどのアルカリ金属とPtをア
ルミナなどの多孔質担体に担持した排ガス浄化用触媒が
提案されている。さらに特開平5-168860号公報には、La
などの希土類元素とPtをアルミナなどの多孔質担体に担
持した排ガス浄化用触媒が提案されている。For example, JP-A-5-317652 proposes an exhaust gas purifying catalyst in which an alkaline earth metal such as Ba and Pt are supported on a porous carrier such as alumina. Japanese Patent Application Laid-Open No. 6-31139 proposes an exhaust gas purifying catalyst in which an alkali metal such as K and Pt are supported on a porous carrier such as alumina. Further, Japanese Patent Laid-Open No. 5-168860 discloses La
An exhaust gas purifying catalyst in which a rare earth element such as and Pt is supported on a porous carrier such as alumina has been proposed.
【０００７】これらの排ガス浄化用触媒を用いれば、空
燃比をリーン側からパルス状にストイキ〜リッチ側とな
るように制御することにより、リーン側ではNOx がアル
カリ土類金属，アルカリ金属及び希土類元素に吸蔵さ
れ、それがストイキ又はリッチ側で放出されてHCやCOな
どの還元性成分と反応して浄化されるため、リーンバー
ンエンジンからの排ガスであってもNOx を効率良く浄化
することができる。このようにNOx の吸蔵・放出作用を
もつアルカリ土類金属、アルカリ金属及び希土類元素を
総称してNOx 吸蔵材といい、近年その利用が活発に行わ
れている。[0007] Using these exhaust gas purifying catalyst, by controlling so that the stoichiometric-rich side in a pulsed manner the air-fuel ratio from the lean side, NO x alkaline earth metal in the lean side, the alkali metals and rare earth occluded in the element, it is because it is released in the stoichiometric or rich side are purified by reacting with reducing components such as HC and CO, to efficiently purify the NO x be a exhaust gas from a lean burn engine Can be. In this way the alkaline earth metal with an absorbing and releasing action of NO x, referred to as the NOx-absorbing material are collectively referred to as alkali metal and rare earth elements, its use has been actively carried out in recent years.
【０００８】上記排ガス浄化用触媒におけるNOx の浄化
反応は、リーン雰囲気において排ガス中のNOを酸化して
NOx とする第１ステップと、NOx 吸蔵材上にNOx を吸蔵
する第２ステップと、ストイキ〜リッチ雰囲気において
NOx 吸蔵材から放出されたNO x を触媒上で還元する第３
ステップとからなることがわかっている。そして第１ス
テップ及び第２ステップを円滑に進行させるためには、
Ptなどの触媒貴金属とNOx 吸蔵材とをできるだけ近接さ
せることが好ましいため、従来の排ガス浄化用触媒で
は、アルミナなどの担体に触媒貴金属とNOx 吸蔵材とを
共存担持している。NO in the exhaust gas purifying catalystxPurification
The reaction oxidizes NO in exhaust gas in a lean atmosphere
NOxAnd the first step, NOxNO on storage materialxOcclude
The second step, and in a stoichiometric-rich atmosphere
NOxNO released from the storage material xThe third of which is reduced over a catalyst
It is known to consist of steps. And the first
In order for the step and the second step to proceed smoothly,
Precious metals such as Pt and NOxAs close as possible to the storage material
It is preferable to use conventional catalysts for exhaust gas purification.
Is a catalyst noble metal and NOxWith occlusion material
Co-supported.
【０００９】[0009]
【発明が解決しようとする課題】ところで、燃料中には
微量ながら硫黄成分が含まれ、これが燃焼時に酸化し、
あるいは触媒上で酸化されてSOx が生成する。このSOx
は酸性であるために、NO x 吸蔵還元型の排ガス浄化用触
媒においては、SOx がアルカリ性のNOx 吸蔵材と反応し
て硫酸塩を生成するという現象が生じる。この結果、NO
x 吸蔵材のNOx 吸蔵能力が失われ、NOx 浄化性能が低下
するという不具合があった。この現象は、NOx 吸蔵材の
硫黄被毒と称されている。By the way, in the fuel,
Contains a small amount of sulfur, which oxidizes during combustion,
Alternatively, it is oxidized on the catalyst to SOxIs generated. This SOx
Is acidic, so NO xStorage reduction type exhaust gas purification catalyst
In the medium, SOxIs alkaline NOxReacts with occlusion material
To produce sulfate. As a result, NO
xNO for occlusion materialxNo storage capacity, NOxPurification performance decreases
There was a problem of doing. This phenomenon is NOxOcclusion material
It is called sulfur poisoning.
【００１０】NOx 吸蔵元素は、NOx と反応して硝酸塩を
生成するが、SOx の存在下では硝酸塩より硫酸塩を生成
しやすいという性質がある。また一旦生成された硫酸塩
は、通常の運転条件では分解しにくいため、NOx 吸蔵元
素のNOx 吸蔵能が復活されにくい。したがってNOx 吸蔵
材は硫黄被毒によりNOx 吸蔵能が次第に消失し、耐久後
にNOx 浄化率が大きく低下するという問題があった。[0010] The NO x storage element reacts with NO x to produce nitrate, but has the property of more easily producing sulfate than nitrate in the presence of SO x . Further, the sulfate once generated is not easily decomposed under normal operating conditions, so that the NO x storage ability of the NO x storage element is not easily restored. Therefore, the NO x storage material has a problem that the NO x storage capacity gradually disappears due to sulfur poisoning, and the NO x purification rate is greatly reduced after endurance.
【００１１】このような不具合を解決するために、リー
ンバーンエンジンの排ガス流路の上流側にSOx を吸蔵す
る触媒を配置し、下流側にNOx 吸蔵還元型の触媒を配置
することが提案されている。この提案によれば、リーン
雰囲気において排ガス中のSO x は上流側の触媒に吸蔵さ
れるため、下流側の触媒の硫黄被毒が防止される。そし
てストイキ〜リッチ雰囲気では、上流側及び下流側の触
媒からそれぞれSOx とNOx が放出され、排ガス中の炭化
水素によって還元浄化される。In order to solve such a problem, a lead
SO upstream of the exhaust gas flow path of the burn enginexOcclude
A catalyst, and NO on the downstream side.xOccupation reduction type catalyst installed
It has been proposed to. According to this proposal, lean
SO in exhaust gas in atmosphere xIs absorbed by the upstream catalyst.
Therefore, sulfur poisoning of the downstream catalyst is prevented. Soshi
In a stoichiometric or rich atmosphere, the upstream and downstream
SO from mediumxAnd NOxIs released and carbonization in exhaust gas
It is reduced and purified by hydrogen.
【００１２】ところが最近の研究により、リーン雰囲気
ばかりでなくリッチ雰囲気においても、NOx 吸蔵材とSO
x との反応が生じることが明らかとなった。したがって
上記の触媒構成においては、リッチ雰囲気で上流側の触
媒から放出されたSOx が下流側の触媒中のNOx 吸蔵材と
反応し、やはり硫黄被毒が生じるという問題がある。ま
た従来の排ガス浄化用触媒においては、リーン雰囲気に
おいてPtに粒成長（シンタリング）が生じ、触媒活性点
の減少により上記第１ステップと第３ステップの反応性
が低下するという不具合がある。そのため高温で使用さ
れると、NOx浄化性能が低下し耐久性が低いことが問題
となっている。However, recent studies have shown that NO x storage materials and SO 2
It was found that a reaction with x occurred. Therefore, in the catalyst structure described above, SO x released from the upstream side of the catalyst reacts with the NO x storage material in the downstream side catalyst in a rich atmosphere, also there is a problem that the sulfur poisoning occurs. Further, in the conventional exhaust gas purifying catalyst, there is a problem that the grain growth (sintering) of Pt occurs in a lean atmosphere, and the reactivity of the first step and the third step is reduced due to a decrease in the catalytic active point. For that reason be used at high temperatures, it the NO x purification performance is low durability and reduced in question.
【００１３】なお、特開平4-122441号公報には、予め熱
処理されたアルミナを用いることにより、アルミナの粒
成長に伴うPtのシンタリングを防止する技術が開示され
ている。ところが、Ptのシンタリングは、アルミナの粒
成長に起因するものばかりではなく、NOx 吸蔵材とPtと
が近接しているとPtのシンタリングが一層促進されるこ
とがわかってきている。しかしNOx 吸蔵材とPtとの距離
が離れていると、上記第２ステップのNOx 吸蔵反応と第
３ステップのNOx 還元反応が生じにくくなり、NOx 浄化
性能が低くなるという問題がある。JP-A-4-122441 discloses a technique for preventing sintering of Pt accompanying the grain growth of alumina by using alumina which has been heat-treated in advance. However, sintering of Pt is not only due to the grain growth of the alumina, when the the NO x storage material and Pt are close to each sintering of Pt has been shown to be further promoted. However, if the distance between the NO x storage material and Pt is large, the NO x storage reaction in the second step and the NO x reduction reaction in the third step are less likely to occur, and the NO x purification performance is reduced. .
【００１４】本発明はこのような事情に鑑みてなされた
ものであり、NOx 吸蔵還元型の触媒において、NOx 吸蔵
材の硫黄被毒を一層抑制するとともに、Ptなどの触媒貴
金属とNOx 吸蔵材とを適切に配置することで触媒貴金属
のシンタリングを抑制することにより、耐久性を一層向
上させることを目的とする。The present invention has been made in view of such circumstances, and in a NO x storage reduction type catalyst, while further suppressing sulfur poisoning of the NO x storage material, the catalyst noble metal such as Pt and NO x An object of the present invention is to further improve durability by suppressing sintering of a catalytic noble metal by appropriately arranging an occluding material.
【００１５】[0015]
【課題を解決するための手段】上記課題を解決する請求
項１に記載の排ガス浄化用触媒の特徴は、第１担体と第
１担体中に含まれたNOx 吸蔵材とよりなるコア部と、第
２担体と第２担体に含まれた触媒貴金属とよりなりコア
部表面に形成された触媒担持層と、からなることにあ
る。Features of the exhaust gas purifying catalyst according to claim 1 to solve the above problems SUMMARY OF THE INVENTION includes more become the core part and the NO x storage material included in the first carrier and the first carrier , A second carrier, and a catalyst noble metal contained in the second carrier, and a catalyst supporting layer formed on the surface of the core portion.
【００１６】請求項２に記載の排ガス浄化用触媒の特徴
は、請求項１に記載の排ガス浄化用触媒において、コア
部と触媒担持層とは重量比でコア部：触媒担持層＝１：
２〜８：１となるように形成されていることにある。請
求項３に記載の排ガス浄化用触媒の特徴は、請求項１に
記載の排ガス浄化用触媒において、NOx 吸蔵材はアルカ
リ金属及びアルカリ土類金属の少なくとも一方から選ば
れ、第２担体は少なくともアルミナを含む金属酸化物で
あることにある。A feature of the exhaust gas purifying catalyst according to the second aspect is that, in the exhaust gas purifying catalyst according to the first aspect, the core part and the catalyst supporting layer are in a weight ratio of core part: catalyst supporting layer = 1: 1.
2 to 8: 1. Wherein the catalyst for purification of exhaust gas according to claim 3, in the catalyst for purification of exhaust gas according to claim 1, NO x storage material is selected from at least one of alkali metals and alkaline earth metals, the second carrier at least It is a metal oxide containing alumina.
【００１７】請求項４に記載の排ガ〜ス浄化用触媒の特
徴は、請求項１に記載の排ガス浄化用触媒において、第
１担体はアルミナとチタニアの複合酸化物からなり、モ
ル比でTiO2/Al2O3=1/2〜1/9 であることにある。請求項
５に記載の排ガス浄化用触媒の特徴は、請求項１に記載
の排ガス浄化用触媒において、触媒貴金属は第２担体と
複合化されていることにある。The exhaust gas purifying catalyst according to claim 4 is characterized in that, in the exhaust gas purifying catalyst according to claim 1, the first support is made of a composite oxide of alumina and titania, and the molar ratio of TiO 2 is TiO 2. 2 / Al 2 O 3 = 1/2 to 1/9. A feature of the exhaust gas purifying catalyst according to claim 5 is that, in the exhaust gas purifying catalyst according to claim 1, the catalytic noble metal is combined with the second carrier.
【００１８】請求項６に記載の排ガ〜ス浄化用触媒の特
徴は、請求項１〜５に記載の排ガス浄化用触媒におい
て、第１担体とNOx 吸蔵材とは複合酸化物を構成してい
ることにある。そして請求項７に記載の排ガス浄化用触
媒の製造方法の特徴は、アルカリ金属及びアルカリ土類
金属の少なくとも一方から選ばれるNOx 吸蔵元素の塩と
第１の金属のアルコキシドとを混合して溶液とし、加水
分解後焼成することによりNOx吸蔵元素と第１の金属と
の複合酸化物よりなるコア部粉末を形成するコア形成工
程と、第２の金属のアルコキシドと貴金属イオンを含む
溶液中とコア部粉末とを混合し、加水分解後焼成するこ
とでコア部粉末表面に貴金属と第２の金属とが複合化し
た触媒担持層を形成する担持層形成工程と、よりなるこ
とにある。The features of the waste gas-scan purifying catalyst according to claim 6, in the catalyst for purification of exhaust gas according to claim 1 to 5, the first carrier and the NO x storage material constitute a composite oxide Is to be. The method for producing an exhaust gas purifying catalyst according to claim 7 is characterized in that a salt of a NO x storage element selected from at least one of an alkali metal and an alkaline earth metal is mixed with an alkoxide of a first metal to form a solution. A core forming step of forming a core portion powder composed of a composite oxide of the NO x occluding element and the first metal by firing after hydrolysis, and a solution containing an alkoxide of the second metal and a noble metal ion. And a supporting layer forming step of forming a catalyst supporting layer in which the noble metal and the second metal are composited on the surface of the core part powder by mixing the core part powder, hydrolyzing and calcining the mixture.
【００１９】さらに請求項８に記載の排ガス浄化用触媒
の製造方法の特徴は、請求項７に記載の製造方法におい
て担持層形成工程はコア部粉末と第２の金属のアルコキ
シドとを含む溶液に貴金属イオンを含む水溶液を添加し
て加水分解することにある。Further, the method for producing an exhaust gas purifying catalyst according to claim 8 is characterized in that, in the production method according to claim 7, the supporting layer forming step comprises the step of forming a solution containing a core portion powder and an alkoxide of the second metal. It is to hydrolyze by adding an aqueous solution containing a noble metal ion.
【００２０】[0020]
【発明の実施の形態】請求項１に記載の排ガス浄化用触
媒では、NOx 吸蔵材は第１担体とともに芯材となるコア
部中に含まれ、触媒貴金属は第２担体とともに表層の触
媒担持層に担持されている。したがって、触媒貴金属と
NOx 吸蔵材とは分離されているので、NOx 吸蔵材による
触媒貴金属のシンタリング促進作用が低下する。これに
よりNO x 浄化性能の耐久性が向上する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The exhaust gas purifying catalyst according to claim 1
In the medium, NOxThe occlusion material is a core that becomes a core material together with the first carrier
The catalytic noble metal is contained in the surface layer together with the second carrier.
It is carried on the medium carrying layer. Therefore, catalytic noble metals
NOxNO because it is separated from the storage materialxBy occlusion material
The sintering promoting action of the catalytic noble metal is reduced. to this
More no xThe durability of the purification performance is improved.
【００２１】一方、触媒貴金属とNOx 吸蔵材とは、分離
されているといえども適度に近接しているため、リーン
雰囲気において排ガス中のNOが酸化されてNOx となる第
１ステップと、NOx 吸蔵材にNOx を吸蔵する第２ステッ
プとが円滑に行われ、かつNO x を還元する第３ステップ
も円滑に行われるため、初期のNOx 浄化性能は従来と同
等に維持される。On the other hand, catalytic noble metal and NOxSeparated from occlusion material
Even though it is reasonably close,
NO in the exhaust gas is oxidized in the atmospherexThe first
One step and NOxNO for storage materialx2nd step to occlude
Is performed smoothly and NO x3rd step to reduce
Is carried out smoothly.xPurification performance is the same as before
Etc. are maintained.
【００２２】つまり、リーン雰囲気においては、排ガス
中のNOは触媒担持層を通過時に触媒貴金属によって酸化
され、生成したNOx は内部のNOx 吸蔵材に効率良く吸蔵
される。そしてストイキ〜リッチ雰囲気では、NOx 吸蔵
材から放出されたNOx は、再び触媒担持層を通過する際
に、触媒貴金属によって雰囲気中に存在するHC及びCOと
反応して、効率よく還元される。これにより初期のNOx
浄化性能は従来と同等に維持される。That is, in the lean atmosphere, NO in the exhaust gas is oxidized by the catalytic noble metal when passing through the catalyst supporting layer, and the generated NO x is efficiently stored in the internal NO x storage material. And in stoichiometric-rich atmosphere, the NO x which is released from the NO x storage material, when passing through the catalyst supporting layer again, reacts with HC and CO present in the atmosphere by the catalytic noble metal is efficiently reduced . As a result, the initial NO x
Purification performance is maintained as before.
【００２３】またSOx はNOx に比べて拡散速度が小さ
い。したがって請求項１に記載の排ガス浄化用触媒にお
いては、NOx は触媒担持層を通過可能であるが、SOx は
触媒担持層を通過することが困難である。したがってリ
ーン雰囲気においては、排ガス中のSOx は触媒担持層の
第２担体に吸着されてコア部まで到達するのが抑制され
るが、NOx は一部が第２担体に吸着されるものの大部分
は触媒担持層を通過してコア部のNOx 吸蔵材に吸蔵され
ると考えられる。SO x has a lower diffusion rate than NO x . Therefore, in the exhaust gas purifying catalyst according to the first aspect, NO x can pass through the catalyst support layer, but SO x cannot pass through the catalyst support layer. Thus in a lean atmosphere, but the SO x in the exhaust gas is inhibited from reaching adsorbed on the second carrier of the catalyst carrying layer to the core portion, of the NO x is what part is attracted to the second carrier Large moiety is considered to be occluded in the NO x storage material of the core portion through the catalyst supporting layer.
【００２４】そしてストイキ〜リッチ雰囲気では、SOx
は第２担体から離脱して排出されるため、NOx 吸蔵材の
被毒は生じない。一方、NOx はNOx 吸蔵材から離脱して
触媒担持層を通過するが、通過する際に触媒担持層中の
触媒貴金属の触媒作用により排ガス中の炭化水素と反応
して還元され、浄化されて排出される。すなわち、SOx
は触媒担持層の第１担体でのみ吸着・離脱を繰り返し、
下層のコア部に接触するのが抑制されているので、NOx
吸蔵材の硫黄被毒を抑制することができる。In a stoichiometric-rich atmosphere, SO x
Since the discharged disengaged from the second carrier, poisoning of the NO x storage material does not occur. On the other hand, the NO x is passed through the catalyst supporting layer is detached from the NO x storage material is reduced by reaction with hydrocarbons in the exhaust gas by the catalytic action of the catalyst noble metal catalyst carrying layer when passing through, is purified Is discharged. That is, SOx
Repeats adsorption and desorption only on the first carrier of the catalyst supporting layer,
Since contact with the lower core is suppressed, NO x
Sulfur poisoning of the storage material can be suppressed.
【００２５】コア部は、第１担体とNOx 吸蔵材を含んで
構成されている。NOx 吸蔵材は、第１担体に単に担持さ
れていてもよいが、第１担体とともに結晶質あるいは非
晶質の複合酸化物として複合化されていることが望まし
い。こうすることによりNOx吸蔵材が原子レベルで高分
散されるため、NOx 吸蔵能が一層向上する。コア部中の
NOx 吸蔵材の含有量としては、第１担体１モルに対して
0.05〜10モルの範囲とすることが望ましい。0.05モル未
満ではNOx 吸蔵能の発現が困難であり、10モルを超えて
含有すると耐熱性が低下するようになる。またコア部の
粒径は、 0.1〜10μｍの範囲が好ましい。粒径が 0.1μ
ｍより小さいと層状構造となりにくく、10μｍより大き
くなると吸蔵材の利用効率が低下する。The core section is configured to include a first carrier and the NO x storage material. The NO x storage material can be simply supported on the first carrier, it is desirable that the complexed with the first carrier as a crystalline or a composite oxide of amorphous. By doing so, the NO x storage material is highly dispersed at the atomic level, so that the NO x storage capacity is further improved. In the core
The content of the NO x occluding material was 1 mol per 1 mol of the first carrier.
It is desirable to set it in the range of 0.05 to 10 mol. If it is less than 0.05 mol, it is difficult to exhibit NO x storage ability, and if it exceeds 10 mol, the heat resistance will be reduced. The core preferably has a particle size of 0.1 to 10 μm. Particle size 0.1μ
If it is smaller than m, it is difficult to form a layered structure.
【００２６】第１担体としては、アルミナ、チタニア、
ジルコニア、シリカ、シリカ−アルミナ、シリカ−チタ
ニア、ゼオライトなどから選択して用いることができ
る。このうちの一種でもよいし複数種類を混合あるいは
複合化して用いることもできる。NOx 吸蔵材は、アルカ
リ金属、アルカリ土類金属及び希土類元素から選ばれる
少なくとも一種を用いることができる。中でもアルカリ
度が高くNOx 吸蔵能の高いアルカリ金属及びアルカリ土
類金属の少なくとも一方を用いるのが好ましい。As the first carrier, alumina, titania,
It can be used by selecting from zirconia, silica, silica-alumina, silica-titania, zeolite and the like. One of these may be used, or a plurality of them may be mixed or combined for use. The NO x storage material can be used at least one selected from alkali metals, alkaline earth metals and rare earth elements. Above all use at least one of the alkalinity is high the NO x storage capacity high alkali metals and alkaline earth metals are preferred.
【００２７】アルカリ金属としては、リチウム、ナトリ
ウム、カリウム、ルビジウム、セシウム、フランシウム
が例示される。アルカリ土類金属とは周期表2A族元素を
いい、バリウム、ベリリウム、マグネシウム、カルシウ
ム、ストロンチウムなどが例示される。また希土類元素
としては、スカンジウム、イットリウム、ランタン、セ
リウム、プラセオジム、ネオジム、ジスプロシウム、イ
ッテルビウムなどが例示される。Examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium, and francium. The alkaline earth metal refers to a Group 2A element in the periodic table, and examples thereof include barium, beryllium, magnesium, calcium, strontium, and the like. Examples of the rare earth element include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, dysprosium, and ytterbium.
【００２８】ところで、NOx 吸蔵材の硫黄被毒を一層抑
制するためには、第１担体としてチタニア（TiO2）とア
ルミナ（ Al2O3）とを併用した担体を用いることが望ま
しい。アルミナにチタニアを添加することにより、NOx
吸蔵材への硫黄酸化物の付着が一層抑制されるととも
に、排ガス雰囲気がリーンからストイキ又はリッチに変
動したときのNOx 吸蔵材と硫黄酸化物との反応生成物の
分解・脱離が促進されるため、硫黄被毒されたNOx 吸蔵
材のNOx 吸蔵能が復活し易い。Incidentally, in order to further suppress the sulfur poisoning of the NO x occluding material, it is desirable to use a carrier in which titania (TiO 2 ) and alumina (Al 2 O 3 ) are used in combination as the first carrier. By adding titania to alumina, NO x
The adhesion of sulfur oxides to the storage material is further suppressed, and the decomposition and desorption of the reaction product between the NO x storage material and the sulfur oxides when the exhaust gas atmosphere fluctuates from lean to stoichiometric or rich is promoted. Therefore, the NO x storage ability of the sulfur-poisoned NO x storage material is easily restored.
【００２９】しかしながら、アルミナとチタニアとを単
に混合しただけの第１担体では、排ガス雰囲気がリーン
からストイキ又はリッチに変動したときのNOx 吸蔵材と
硫黄酸化物との反応生成物の分解促進効果は充分ではな
く、排ガス温度が 600℃程度の高温耐久試験時には第１
担体に劣化が生じて耐久性に不足する場合がある。この
ような不具合を抑制するには、アルミナとチタニアとの
複合酸化物から第１担体を形成することが望ましい。こ
れにより耐久性が一層向上し、NOx 吸蔵材の硫黄被毒が
一層抑制される。However, in the case of the first carrier in which alumina and titania are simply mixed, the effect of accelerating the decomposition of the reaction product between the NO x occluding material and the sulfur oxide when the exhaust gas atmosphere changes from lean to stoichiometric or rich. Is not sufficient, and the exhaust gas temperature is about 600 ° C.
In some cases, the carrier is deteriorated and the durability is insufficient. In order to suppress such a problem, it is desirable to form the first carrier from a composite oxide of alumina and titania. Thereby, the durability is further improved, and the sulfur poisoning of the NO x storage material is further suppressed.
【００３０】第１担体をアルミナとチタニアとの複合酸
化物から構成する場合には、モル比でTiO2/Al2O3=1/2〜
1/9 の範囲とすることが望ましい。チタニアの量がこの
範囲より少ないとチタニアを添加した効果が小さくNOx
浄化能が低下し、チタニアの量がこの範囲を超えると耐
熱性が低下するためかNOx 浄化能が低下する。特に望ま
しい範囲はTiO2/Al2O= 1/4〜 1/9である。When the first carrier is composed of a composite oxide of alumina and titania, the molar ratio of TiO 2 / Al 2 O 3 = 1 / 2-
It is desirable to set the range to 1/9. If the amount of titania is less than this range, the effect of adding titania is small and NO x
Purifying ability is lowered, the amount of titania is the NO x purification performance is deteriorated or to decrease the heat resistance exceeds this range. A particularly desirable range is TiO 2 / Al 2 O = 1/4 to 1/9.
【００３１】触媒担持層は第２担体と触媒貴金属とから
構成される。第２担体としては、アルミナ、チタニア、
ジルコニア、シリカ、シリカ−アルミナ、シリカ−チタ
ニア、ゼオライトなどから選択して用いることができ
る。このうちの一種でもよいし複数種類を混合あるいは
複合化して用いることもできる。SO2 を吸着し易く、か
つ吸着したSO2 が脱離し易いものが特に望ましく、アル
ミナが最も望ましい。なお第１担体と第２担体とは、同
一材質であってもよいし異材質であってもよい。The catalyst supporting layer is composed of a second carrier and a noble metal catalyst. As the second carrier, alumina, titania,
It can be used by selecting from zirconia, silica, silica-alumina, silica-titania, zeolite and the like. One of these may be used, or a plurality of them may be mixed or combined for use. Easily adsorbs SO 2, and adsorbed SO 2 is particularly preferably those easily desorbed alumina is most desirable. The first carrier and the second carrier may be made of the same material or different materials.
【００３２】触媒担持層は、アルミナのみから構成して
もよいし、チタニアやジルコニアなどを単独酸化物であ
るいはアルミナと複合化して含むこともできる。さら
に、CeO2 、CeO2 −ZrO2 を含ませることもできる。こ
れにより触媒貴金属のシンタリングが一層抑制され、耐
熱性が一層向上する。チタニアやジルコニアなどの含有
量は、触媒担持層に0.01〜70重量％程度が好ましい。チ
タニアやジルコニアなどが0.01重量％より少ないと効果
が不十分となり、70重量％より多くなると担体の耐熱性
が不十分となる。The catalyst supporting layer may be composed of alumina alone, or may contain titania, zirconia, or the like as a single oxide or as a composite with alumina. Further, CeO 2 or CeO 2 —ZrO 2 may be included. Thereby, sintering of the catalytic noble metal is further suppressed, and the heat resistance is further improved. The content of titania and zirconia is preferably about 0.01 to 70% by weight in the catalyst supporting layer. If the content of titania or zirconia is less than 0.01% by weight, the effect is insufficient, and if it is more than 70% by weight, the heat resistance of the carrier becomes insufficient.
【００３３】また触媒担持層に遷移金属を含むことも好
ましい。遷移金属を含むことによりSOx の吸着・離脱が
一層活発となり、その結果NOx 吸蔵材とSOx とが接触す
る機会が一層減少するため、NOx 吸蔵材の硫黄被毒を一
層抑制することができる。このような遷移金属として
は、ニッケル、バナジウム、鉄などが例示され、その含
有量はアルミナ層に１〜50重量％程度が好ましい。遷移
金属が１重量％より少ないと効果が不十分となり、50重
量％より多くなると耐熱性が不十分となる。It is also preferable that the catalyst supporting layer contains a transition metal. By including the transition metal, the adsorption and desorption of SO x becomes more active, and as a result, the chance of contact between the NO x storage material and SO x is further reduced, so that the sulfur poisoning of the NO x storage material is further suppressed. Can be. Examples of such a transition metal include nickel, vanadium, and iron, and the content thereof is preferably about 1 to 50% by weight in the alumina layer. If the amount of the transition metal is less than 1% by weight, the effect becomes insufficient, and if it exceeds 50% by weight, the heat resistance becomes insufficient.
【００３４】一方、触媒貴金属としては、Pt、Rh、パラ
ジウム（Pd）、銀（Ag）、金（Au）、イリジウム（Ir）
などが例示される。この触媒貴金属の担持量は、触媒貴
金属が 0.5〜20重量％の範囲で任意に選択することがで
きる。触媒貴金属の担持量が0.5重量％より少ないとNO
x 浄化性能が低下して実用的ではなく、20重量％より多
く担持してもNOx 浄化性能が飽和するとともにコストの
高騰を招く。特に望ましい担持量は、１〜10重量％であ
る。On the other hand, noble metals such as Pt, Rh, palladium (Pd), silver (Ag), gold (Au), iridium (Ir)
And the like. The amount of the catalytic noble metal carried can be arbitrarily selected within the range of 0.5 to 20% by weight of the catalytic noble metal. If the supported amount of catalytic noble metal is less than 0.5% by weight, NO
x purifying performance impractical reduced, the cost is soaring along with 20 wt% more carrying the NO x purification performance even when saturated. A particularly desirable loading is from 1 to 10% by weight.
【００３５】触媒貴金属は、触媒担持層に担持された状
態で存在していてもよいが、第２担体と複合化された状
態で触媒担持層に複合担持されていることが望ましい。
このようにすれば触媒貴金属が原子レベルで第２担体中
に均一に分散した状態となるため、触媒貴金属の移動が
防止されシンタリングが抑制される。したがって耐熱性
が向上し、耐久試験後も触媒貴金属の比表面積を大きく
維持できるためNOx 浄化性能が向上する。The catalyst noble metal may be present in a state of being supported on the catalyst supporting layer, but is preferably supported on the catalyst supporting layer in a state of being composited with the second carrier.
By doing so, the catalyst noble metal is uniformly dispersed in the second carrier at the atomic level, so that movement of the catalyst noble metal is prevented and sintering is suppressed. Therefore, the heat resistance is improved, and the specific surface area of the catalytic noble metal can be kept large even after the durability test, so that the NO x purification performance is improved.
【００３６】そして触媒貴金属は触媒担持層にのみ担持
又は複合担持され、NOx は必ず触媒担持層を通過して出
入りするため、担持された触媒貴金属全てがNOx の還元
に寄与する。したがって含まれている触媒貴金属を有効
に利用することができる。Ptのシンタリングを一層抑制
するためにRhを共存させることが好ましいことが知られ
ているが、本発明においてもPtとともにRhを担持させる
ことができる。Rhは触媒担持層にPtと共存担持させても
よいし、コア部にNOx 吸蔵材と共存させてもPtのシンタ
リングを抑制する効果が得られる。The catalyst noble metal is supported on or supported only on the catalyst support layer, and NO x always passes through the catalyst support layer and enters and exits, so that all the supported catalyst noble metal contributes to the reduction of NO x . Therefore, the contained catalyst noble metal can be effectively used. It is known that it is preferable to make Rh coexist in order to further suppress sintering of Pt, but Rh can be supported together with Pt in the present invention. Rh may be co-supported with Pt on the catalyst support layer, or an effect of suppressing Pt sintering may be obtained by co-existing with the NO x storage material in the core.
【００３７】コア部と触媒担持層の構成比率は、請求項
２に記載のように、重量比でコア部：触媒担持層＝１：
２〜８：１の範囲が好ましい。触媒担持層の比率がこの
範囲より少ないと、所定量の触媒貴金属を担持した場合
に触媒貴金属が高密度となり、かつNOx 吸蔵材と触媒貴
金属との距離が近接しすぎるために、触媒貴金属のシン
タリングが促進されるようになる。また触媒担持層の比
率がこの範囲より多いと、触媒貴金属が低密度となって
第２担体中に埋没し、触媒貴金属の露出面積が低下する
ことによりNOx 浄化性能が低下するようになる。The composition ratio of the core part and the catalyst supporting layer is, as described in claim 2, the core part: the catalyst supporting layer = 1:
A range of 2 to 8: 1 is preferred. When the ratio of the catalyst supporting layer is less than this range, for catalytic noble metal it becomes dense, and too close the distance between the NO x storage material and the catalyst noble metal when carrying a predetermined amount of catalytic noble metal, the noble metal catalyst Sintering will be promoted. Further, when the ratio of the catalyst supporting layer is higher than this range, the catalyst noble metal is embedded in the second carrier in the low-density, NO x purification performance by the exposed area of the catalyst noble metal is lowered will be lowered.
【００３８】さらに、触媒担持層の厚さがあまり薄い
と、SOx が触媒担持層を通過してNOx吸蔵材と接触する
確率が高くなるため好ましくない。またあまり厚くなり
すぎると、NOx の通過も困難となってNOx 吸蔵材への吸
蔵が困難となる。したがって触媒担持層の厚さには最適
範囲があり、コア部の粒径の 1/100〜 1/2程度の範囲が
好ましい。Further, if the thickness of the catalyst supporting layer is too small, the probability that SO x passes through the catalyst supporting layer and comes into contact with the NO x storage material is undesirably high. Also, if too too thick, storage to the NO x storage material it is difficult to become also the passage of the NO x difficult. Therefore, there is an optimum range for the thickness of the catalyst supporting layer, and a range of about 1/100 to 1/2 of the particle size of the core is preferable.
【００３９】本発明の排ガス浄化用触媒を形成する請求
項７に記載の排ガス浄化用触媒の製造方法では、先ずコ
ア形成工程において、アルカリ金属及びアルカリ土類金
属の少なくとも一方から選ばれるNOx 吸蔵元素の塩と第
１の金属のアルコキシドとが混合され、加熱により溶液
とされる。この溶液に水を加えることで加水分解が生
じ、ゾル−ゲル反応により第１の金属がNOx 吸蔵元素を
取り込んだ形のゲルが生成する。このゲルを乾燥後粉砕
し、それを焼成することによりNOx 吸蔵元素と第１の金
属との複合酸化物よりなるコア部粉末が形成される。[0039] In the method for producing an exhaust gas purifying catalyst according to claim 7 for forming the exhaust gas purifying catalyst of the present invention, first, in the core forming step, NO x storage selected from at least one of an alkali metal and an alkaline earth metal is provided. The salt of the element and the alkoxide of the first metal are mixed and heated to form a solution. The solution resulting hydrolysis by the addition of water, the sol - first metallic gel reaction is the NO x storage element taken the form of a gel is produced. The gel is dried, pulverized, and baked to form a core powder composed of a composite oxide of the NO x occluding element and the first metal.
【００４０】第１の金属としては、Al，Ti，Si，Zrなど
が例示される。またアルカリ金属及びアルカリ土類金属
としては、前述した元素が例示される。次の担持層形成
工程では、第２の金属のアルコキシドと貴金属イオンを
含む溶液とコア部粉末とを混合し、加水分解後焼成する
ことでコア部粉末表面に貴金属と第２の金属とが複合化
した触媒担持層が形成される。Examples of the first metal include Al, Ti, Si, Zr and the like. Examples of the alkali metal and the alkaline earth metal include the above-described elements. In the next supporting layer forming step, the solution containing the alkoxide of the second metal and the noble metal ion is mixed with the core powder, and the mixture is hydrolyzed and fired, so that the noble metal and the second metal are combined on the surface of the core powder. The converted catalyst supporting layer is formed.
【００４１】第２の金属としては、Al，Ti，Si，Zrなど
が例示される。また貴金属イオンを構成する貴金属とし
ては、前述した触媒貴金属が例示される。そして担持層
形成工程では、加水分解によるゾル−ゲル反応により、
第２の金属がコア部粉末表面に貴金属イオンを取り込ん
だ形で析出する。これを乾燥・焼成することにより、コ
ア部粉末表面に貴金属と第２の金属とが複合化した触媒
担持層が形成される。Examples of the second metal include Al, Ti, Si, Zr and the like. The noble metal constituting the noble metal ion is exemplified by the above-mentioned catalytic noble metal. Then, in the support layer forming step, by a sol-gel reaction due to hydrolysis,
The second metal precipitates on the surface of the core portion powder in a state where the noble metal ions are taken in. By drying and firing this, a catalyst supporting layer in which the noble metal and the second metal are composited is formed on the surface of the core powder.
【００４２】担持層形成工程では、例えば水分の存在し
ない系で第２の金属のアルコキシドと貴金属イオンとを
含む溶液を調製し、コア部粉末を添加した後水を加える
ことで加水分解反応が生じる。このとき、コア部粉末表
面の吸着水のみを水分源とすることもできるが、この場
合には形成される触媒担持層の厚さがきわめて薄くなる
ため、触媒貴金属のシンタリングが生じ易くなり好まし
くない。したがって第２の金属のアルコキシドと貴金属
イオンとを含む溶液にコア部粉末を混合した後、加水分
解反応に必要十分な水分を添加することが望ましい。In the support layer forming step, for example, a solution containing an alkoxide of the second metal and a noble metal ion is prepared in a system free of moisture, and after a core powder is added, water is added to cause a hydrolysis reaction. . At this time, only the water adsorbed on the surface of the core portion powder can be used as a water source. However, in this case, since the thickness of the formed catalyst supporting layer is extremely thin, sintering of the catalyst noble metal is liable to occur. Absent. Therefore, after mixing the core powder with the solution containing the alkoxide of the second metal and the noble metal ion, it is desirable to add water necessary and sufficient for the hydrolysis reaction.
【００４３】また請求項８に記載されたように、コア部
粉末と第２の金属のアルコキシドとを含む溶液に貴金属
イオンを含む水溶液を添加して加水分解することも好ま
しい。本発明の製造方法によれば、NOx 吸蔵元素と第１
の金属とが原子レベルで高分散したコア部粉末を容易か
つ確実に形成することができ、かつ貴金属と第２の金属
とが原子レベルで高分散した触媒担持層をコア部粉末表
面に容易かつ確実に形成することができる。As described in claim 8, it is also preferable to add an aqueous solution containing a noble metal ion to a solution containing the core powder and the alkoxide of the second metal for hydrolysis. According to the production method of the present invention, NO x storage element and the first
Can easily and reliably form a core powder in which the metal of the metal is highly dispersed at the atomic level, and a catalyst supporting layer in which the noble metal and the second metal are highly dispersed at the atomic level can be easily and easily formed on the surface of the core powder. It can be formed reliably.
【００４４】そして得られた触媒粉末は、コーディエラ
イトやメタルから形成されたハニカム形状の担体基材や
ペレット形状の担体基材に付着させてコート層を形成す
ることで、排ガス浄化用触媒として用いられる。場合に
よっては、得られた触媒粉末のみからペレット形状など
に形成することもできる。The obtained catalyst powder is adhered to a honeycomb-shaped carrier substrate or a pellet-shaped carrier substrate made of cordierite or metal to form a coat layer, thereby forming an exhaust gas purifying catalyst. Used. In some cases, it can be formed into a pellet shape or the like from only the obtained catalyst powder.
【００４５】[0045]
【実施例】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。 （実施例１）図１に本実施例の排ガス浄化用触媒の概念
的な断面図を示す。この排ガス浄化用触媒は触媒粉末１
の集合体よりなり、触媒粉末１はコア部10と、コア部10
表面に形成されたアルミナ層11とから構成されている。
コア部10はアルミナからなり、NOx 吸蔵材としてのBaが
担持されている。またアルミナ層11には、触媒貴金属と
してのPtが担持されている。The present invention will be specifically described below with reference to examples and comparative examples. (Embodiment 1) FIG. 1 shows a conceptual cross-sectional view of an exhaust gas purifying catalyst of this embodiment. This exhaust gas purifying catalyst is a catalyst powder 1
, And the catalyst powder 1 comprises a core 10 and a core 10
And an alumina layer 11 formed on the surface.
The core portion 10 is made of alumina, Ba as the NO x storage material is supported. The alumina layer 11 carries Pt as a catalytic noble metal.
【００４６】以下、この排ガス浄化用触媒の製造方法を
説明して構成の詳細な説明に代える。γ−アルミナ粉末
に所定濃度の酢酸バリウム水溶液の所定量を含浸させ、
120℃で12時間乾燥し 500℃で１時間焼成して、アルミ
ナにBaを担持したコア部粉末を形成した。Baはコア部粉
末中に20重量％含まれている。Hereinafter, the method for producing the exhaust gas purifying catalyst will be described, and the detailed description of the structure will be replaced. γ-alumina powder impregnated with a predetermined amount of barium acetate aqueous solution of a predetermined concentration,
The resultant was dried at 120 ° C. for 12 hours and calcined at 500 ° C. for 1 hour to form a core powder in which Ba was supported on alumina. Ba is contained at 20% by weight in the core powder.
【００４７】一方、Al(O-secC4H9)3を2-プロパノールに
0.05モル／Ｌとなるように溶解した溶液を調製した。こ
の溶液の所定量中に上記コア部粉末の所定量を混合し、
室温で１時間攪拌後、濾過・洗浄し、 120℃で12時間乾
燥後 500℃で１時間焼成して、ゾル・ゲル法によりコア
部粉末表面にアルミナ層を形成した。そして、得られた
アルミナ層をもつコア部粉末に所定濃度のジニトロジア
ンミン白金硝酸水溶液の所定量を含浸し、Ptを含浸担持
した。Ptの担持量は1.45重量％である。得られた触媒粉
末から定法によりペレットを作製し、本実施例の排ガス
浄化用触媒とした。On the other hand, Al (O-secC 4 H 9 ) 3 is converted to 2-propanol.
A solution was prepared by dissolving so as to be 0.05 mol / L. Mix a predetermined amount of the core powder into a predetermined amount of this solution,
After stirring at room temperature for 1 hour, the mixture was filtered, washed, dried at 120 ° C. for 12 hours, and then calcined at 500 ° C. for 1 hour to form an alumina layer on the surface of the core powder by a sol-gel method. Then, the obtained core portion powder having an alumina layer was impregnated with a predetermined amount of a dinitrodiammineplatinum nitric acid aqueous solution having a predetermined concentration, and impregnated with Pt. The carried amount of Pt is 1.45% by weight. Pellets were produced from the obtained catalyst powder by a conventional method, and used as an exhaust gas purifying catalyst of this example.
【００４８】（実施例２）2-プロパノール中にAl(O-sec
C4H9)3を0.05モル／Ｌと、硝酸ニッケルを0.01モル／Ｌ
溶解した溶液を調製し、この溶液の所定量中に実施例１
にて形成されたものと同様のコア部粉末の所定量を混合
して、室温で１時間攪拌後、濾過・洗浄し、 120℃で１
２時間乾燥後 500℃で１時間焼成して、ゾル・ゲル法に
よりコア部粉末表面にアルミナ層を形成した。Example 2 Al (O-sec) in 2-propanol
C 4 H 9 ) 3 is 0.05 mol / L and nickel nitrate is 0.01 mol / L.
A dissolved solution was prepared, and Example 1 was dissolved in a predetermined amount of this solution.
A predetermined amount of the same core powder as that formed in the above was mixed and stirred at room temperature for 1 hour, followed by filtration and washing.
After drying for 2 hours, the resultant was baked at 500 ° C. for 1 hour to form an alumina layer on the surface of the core powder by a sol-gel method.
【００４９】そして、得られたアルミナ層をもつコア部
粉末に所定濃度のジニトロジアンミン白金硝酸水溶液の
所定量を含浸し、Ptを含浸担持した。Ptの担持量は１．
４１重量％である。得られた触媒粉末から定法によりペ
レットを作製し、本実施例の排ガス浄化用触媒とした。 （実施例３）2-プロパノール中にAl(O-secC4H9)3を0.05
モル／Ｌと、Ti(O-secC4H9)3を0.01モル／Ｌ溶解した溶
液を調製し、この溶液の所定量中に実施例１にて形成さ
れたものと同様のコア部粉末の所定量を混合して、室温
で１時間攪拌後、濾過・洗浄し、 120℃で12時間乾燥後
500℃で１時間焼成して、ゾル・ゲル法によりコア部粉
末表面にアルミナ層を形成した。Then, the core powder having the alumina layer obtained was impregnated with a predetermined amount of a dinitrodiammineplatinum nitric acid aqueous solution having a predetermined concentration, and was impregnated with Pt. The supported amount of Pt is 1.
It is 41% by weight. Pellets were produced from the obtained catalyst powder by a conventional method, and used as an exhaust gas purifying catalyst of this example. (Example 3) Al (O-secC 4 H 9 ) 3 was added to 0.05% in 2-propanol.
A solution prepared by dissolving 0.01 mol / L of Ti (O-secC 4 H 9 ) 3 and 0.01 mol / L of Ti (O-secC 4 H 9 ) 3 was prepared. The same core powder as that formed in Example 1 was prepared in a predetermined amount of this solution. Mix predetermined amount, stir at room temperature for 1 hour, filter and wash, and dry at 120 ° C for 12 hours
After baking at 500 ° C. for 1 hour, an alumina layer was formed on the surface of the core powder by the sol-gel method.
【００５０】そして、得られたアルミナ層をもつコア部
粉末に所定濃度のジニトロジアンミン白金硝酸水溶液の
所定量を含浸し、Ptを含浸担持した。Ptの担持量は1.46
重量％である。得られた触媒粉末から定法によりペレッ
トを作製し、本実施例の排ガス浄化用触媒とした。 （実施例４）2-プロパノール中にAl(O-secC4H9)3を0.05
モル／Ｌと、塩化白金酸を0.05モル／Ｌ溶解した溶液を
調製し、この溶液の所定量中に実施例１にて形成された
ものと同様のコア部粉末の所定量を混合して、室温で１
時間攪拌後、濾過・洗浄し、120℃で12時間乾燥後 500
℃で１時間焼成して、ゾル・ゲル法によりPtを複合担持
したアルミナ層をコア部粉末表面に形成し、Ptが1.5重
量％複合担持された触媒粉末を調製した。Then, the core powder having the alumina layer obtained was impregnated with a predetermined amount of an aqueous solution of dinitrodiammineplatinic nitric acid having a predetermined concentration, and was impregnated with Pt. Pt loading is 1.46
% By weight. Pellets were produced from the obtained catalyst powder by a conventional method, and used as an exhaust gas purifying catalyst of this example. (Example 4) Al (O-secC 4 H 9 ) 3 was added to 0.05% in 2-propanol.
A solution prepared by dissolving 0.05 mol / L of chloroplatinic acid and 0.05 mol / L of chloroplatinic acid was mixed with a predetermined amount of the same core powder as that formed in Example 1 in a predetermined amount of this solution. 1 at room temperature
After stirring for an hour, filter and wash, and after drying at 120 ° C for 12 hours, 500
The mixture was baked at 1 ° C. for 1 hour to form a Pt composite-supported alumina layer on the surface of the core powder by the sol-gel method, to prepare a catalyst powder having Pt composite-supported by 1.5% by weight.
【００５１】そして、得られた触媒粉末から定法により
ペレットを作製し、本実施例の排ガス浄化用触媒とし
た。 （実施例５）2-プロパノール中にAl(O-secC4H9)3を0.05
モル／Ｌと、塩化白金酸を0.05モル／Ｌ、さらにTi(O-s
ecC4H9)3を0.01モル／Ｌ溶解した溶液を調製し、この溶
液の所定量中に実施例１にて形成されたものと同様のコ
ア部粉末の所定量を混合して、室温で１時間攪拌後、濾
過・洗浄し、 120℃で12時間乾燥後 500℃で１時間焼成
して、ゾル・ゲル法によりPtを複合担持したアルミナ層
をコア部粉末表面に形成し、Ptが 1.5重量％複合担持さ
れた触媒粉末を調製した。Then, pellets were prepared from the obtained catalyst powder by an ordinary method, and used as an exhaust gas purifying catalyst of this example. (Example 5) Al in 2-propanol (O-secC 4 H 9) 3 0.05
Mol / L, 0.05 mol / L of chloroplatinic acid, and Ti (Os
A solution prepared by dissolving ecC 4 H 9 ) 3 in a concentration of 0.01 mol / L was prepared, and a predetermined amount of the same core powder as that formed in Example 1 was mixed into a predetermined amount of this solution. After stirring for 1 hour, filtration and washing, drying at 120 ° C. for 12 hours, and calcining at 500 ° C. for 1 hour, an alumina layer supporting Pt complex was formed on the surface of the core powder by a sol-gel method. A catalyst powder supporting the composite by weight was prepared.
【００５２】そして、得られた触媒粉末から定法により
ペレットを作製し、本実施例の排ガス浄化用触媒とし
た。 （実施例６）バリウムアルコキシドとAl(O-secC4H9)3の
混合プロパノール溶液から、ゾル・ゲル法によりBaO・4A
l2O3なる組成の複合酸化物よりなるコア部粉末を調製し
た。Then, pellets were prepared from the obtained catalyst powder by a conventional method, and used as an exhaust gas purifying catalyst of this example. Example 6 BaO.4A was prepared from a mixed propanol solution of barium alkoxide and Al (O-secC 4 H 9 ) 3 by a sol-gel method.
A core powder composed of a composite oxide having a composition of l 2 O 3 was prepared.
【００５３】一方、Al(O-secC4H9)3を2-プロパノールに
0.05モル／Ｌとなるように溶解した溶液を調製した。こ
の溶液の所定量中に上記コア部粉末の所定量を混合し、
室温で１時間攪拌後、濾過・洗浄し、 120℃で12時間乾
燥後 500℃で１時間焼成して、ゾル・ゲル法によりコア
部粉末表面にアルミナ層を形成した。そして、得られた
アルミナ層をもつコア部粉末に所定濃度のジニトロジア
ンミン白金硝酸水溶液の所定量を含浸し、Ptを含浸担持
した。Ptの担持量は1.40重量％である。得られた触媒粉
末から定法によりペレットを作製し、本実施例の排ガス
浄化用触媒とした。On the other hand, Al (O-secC 4 H 9 ) 3 was converted to 2-propanol.
A solution was prepared by dissolving so as to be 0.05 mol / L. Mix a predetermined amount of the core powder into a predetermined amount of this solution,
After stirring at room temperature for 1 hour, the mixture was filtered, washed, dried at 120 ° C. for 12 hours, and then calcined at 500 ° C. for 1 hour to form an alumina layer on the surface of the core powder by a sol-gel method. Then, the obtained core portion powder having an alumina layer was impregnated with a predetermined amount of a dinitrodiammineplatinum nitric acid aqueous solution having a predetermined concentration, and impregnated with Pt. The carried amount of Pt is 1.40% by weight. Pellets were produced from the obtained catalyst powder by a conventional method, and used as an exhaust gas purifying catalyst of this example.
【００５４】（比較例１）実施例１にて形成されたもの
と同様のコア部粉末に所定濃度のジニトロジアンミン白
金硝酸水溶液の所定量を含浸し、Ptを含浸担持した。Pt
の担持量は１．５重量％である。得られた触媒粉末から
定法によりペレットを作製し、本比較例の排ガス浄化用
触媒とした。Comparative Example 1 A core powder similar to that formed in Example 1 was impregnated with a predetermined amount of a dinitrodiammineplatinum nitric acid aqueous solution having a predetermined concentration, and was impregnated with Pt. Pt
Is 1.5% by weight. Pellets were prepared from the obtained catalyst powder by a conventional method, and used as an exhaust gas purifying catalyst of this comparative example.
【００５５】（評価試験）上記した各実施例及び比較例
のペレットをモデルガス耐久装置に装着し、表１に示す
リーンモデルガス（空燃比A/F=21）とリッチモデルガス
（空燃比A/F=12）を、入ガス温度 350℃、空間速度10万
hr-1の条件で流し、リーン時のHC、CO及びNOx 浄化率を
それぞれ測定して初期浄化率とした。(Evaluation Test) The pellets of the above Examples and Comparative Examples were mounted on a model gas durable apparatus, and a lean model gas (air-fuel ratio A / F = 21) and a rich model gas (air-fuel ratio A) shown in Table 1 were obtained. / F = 12), with an input gas temperature of 350 ° C and a space velocity of 100,000
flowing under the conditions of hr -1, and the initial purification rate was measured lean upon HC, CO and NO x purification rate, respectively.
【００５６】また表１に示すリーンモデルガスを４分間
と、リッチモデルガスを30秒間交互に流すのを、入りガ
ス温度 700℃、SV＝10万hr-1で20時間行う耐久試験を行
った。その後初期浄化率と同様にHC、CO及びNOx 浄化率
を測定し、熱処理後の浄化率とした。結果を表２に示
す。なお、浄化率は次式により算出した。 浄化率（％）＝ 100×（入ガス中成分量−出ガス中成分
量）／入ガス中成分量An endurance test was conducted in which the lean model gas shown in Table 1 was alternately supplied for 4 minutes and the rich model gas was alternately supplied for 30 seconds at an input gas temperature of 700 ° C. and an SV of 100,000 hr −1 for 20 hours. . Then similarly to the initial purification rate HC, measured CO and NO x purification rate, and the purification rate after the heat treatment. Table 2 shows the results. The purification rate was calculated by the following equation. Purification rate (%) = 100 x (incoming gas component amount-outgoing gas component amount) / incoming gas component amount
【００５７】[0057]
【表１】 [Table 1]
【００５８】[0058]
【表２】 （評価）表２より、比較例１の触媒は各実施例の触媒に
比べて耐久後のNOx 浄化率が低く、各実施例の触媒は比
較例に比べて高いNOx 浄化率を示している。これはBaと
アルミナからなる担体にPtを含むアルミナ層を設けた効
果であることが明らかである。[Table 2] (Evaluation) From Table 2, the catalyst of Comparative Example 1 has low the NO x purification ratio after endurance as compared with the catalyst of each example, the catalyst of each example shows high the NO x purification rate in comparison with Comparative Example I have. This is apparently the effect of providing an alumina layer containing Pt on a carrier made of Ba and alumina.
【００５９】そして実施例１と実施例２〜３の比較よ
り、アルミナ層にNi又はTiを複合することにより耐久後
のNOx 浄化率が一層向上していることがわかる。また実
施例１〜３と実施例４〜５の比較より、アルミナ層にPt
を複合化することにより耐久後のHC及びCO浄化率が大き
く向上するとともにNOx 浄化率も僅かながら向上し、Pt
のシンタリングが防止された効果が得られている。From the comparison between Example 1 and Examples 2-3, it can be seen that the composite of Ni or Ti in the alumina layer further improves the NO x purification rate after durability. Also, from the comparison between Examples 1 to 3 and Examples 4 and 5, Pt was added to the alumina layer.
The improved slightly also the NO x purification rate with HC and CO purification rate after the durability is significantly improved by complexing, Pt
The effect of preventing sintering is obtained.
【００６０】（実施例７）図２に本実施例の排ガス浄化
用触媒の概念的な断面図を示す。この排ガス浄化用触媒
は触媒粉末２の集合体よりなり、触媒粉末２はコア部20
と、コア部20表面に形成された触媒担持層21とから構成
されている。コア部20はアルミナからなり、NOx 吸蔵材
としてのBaが担持されている。また触媒担持層21はPtが
複合化されたアルミナから構成されている。(Embodiment 7) FIG. 2 is a conceptual sectional view of an exhaust gas purifying catalyst of this embodiment. This exhaust gas purifying catalyst is composed of an aggregate of the catalyst powder 2, and the catalyst powder 2 is composed of a core 20.
And a catalyst supporting layer 21 formed on the surface of the core portion 20. The core portion 20 made of alumina, Ba as the NO x storage material is supported. The catalyst support layer 21 is made of alumina in which Pt is compounded.
【００６１】以下、この排ガス浄化用触媒の製造方法を
説明して構成の詳細な説明に代える。 ＜コア部粉末の形成＞平均粒径10μｍの活性アルミナ粉
末 100ｇに所定濃度の酢酸バリウム水溶液の所定量を含
浸させ、 110℃で３時間乾燥後、 500℃で２時間焼成し
Baを担持してコア部粉末20を形成した。コア部粉末20中
のBaの担持量は、アルミナ 100ｇ当たり 0.1モルであ
る。Hereinafter, the method for producing the exhaust gas purifying catalyst will be described, and the detailed description of the constitution will be replaced. <Formation of core powder> 100 g of activated alumina powder having an average particle size of 10 μm is impregnated with a predetermined amount of a barium acetate aqueous solution having a predetermined concentration, dried at 110 ° C. for 3 hours, and baked at 500 ° C. for 2 hours.
The core part powder 20 was formed by carrying Ba. The amount of Ba supported in the core powder 20 is 0.1 mol per 100 g of alumina.
【００６２】＜触媒担持層の形成＞次に、ステンレス容
器中に所定量のイソプロピルアルコールを入れ、トリイ
ソプロポキシアルミニウム Al(OC3H7)3 を Al2O3換算で
100ｇとなるように混合溶解し、そこへ上記で得られた
コア部粉末を 100ｇ混合してよく攪拌分散させ、80℃で
白金アンミン水酸塩水溶液を滴下した。これによりトリ
イソプロポキシアルミニウムが加水分解し、Ptを含むア
ルミナからなるゲルがコア部粉末表面に形成された。こ
れを加熱して溶媒を蒸発させ、窒素ガス雰囲気中で仮焼
後、大気中 500℃で３時間焼成して、コア部粉末表面に
触媒担持層21を形成した。<Formation of Catalyst Supporting Layer> Next, a predetermined amount of isopropyl alcohol was put in a stainless steel container, and triisopropoxyaluminum Al (OC 3 H 7 ) 3 was converted into Al 2 O 3 .
100 g of the core powder obtained above was mixed and dispersed well with stirring, and an aqueous solution of platinum ammine hydroxide was added dropwise at 80 ° C. As a result, triisopropoxyaluminum was hydrolyzed, and a gel made of alumina containing Pt was formed on the surface of the core powder. This was heated to evaporate the solvent, calcined in a nitrogen gas atmosphere, and then calcined in the air at 500 ° C. for 3 hours to form a catalyst supporting layer 21 on the surface of the core powder.
【００６３】触媒担持層21はコア部20に対して重量比で
1/1に形成され、触媒担持層21中にはアルミナ 100ｇ当
たり２ｇのPtが複合化されている。つまり得られた触媒
粉末においては、触媒粉末 200ｇ当たりにBaが 0.1モル
担持され、Ptが２ｇ複合担持されていることになる。 ＜触媒の調製＞上記触媒粉末を用い、定法により直径２
〜３mmのペレット形状に成形してペレット触媒を調製し
た。The catalyst supporting layer 21 is in a weight ratio with respect to the core 20.
2 g of Pt is compounded per 100 g of alumina in the catalyst support layer 21. That is, in the obtained catalyst powder, 0.1 mol of Ba is supported per 200 g of the catalyst powder, and 2 g of Pt is supported in a composite manner. <Preparation of catalyst>
A pellet catalyst was prepared by molding into a pellet shape of ３3 mm.
【００６４】＜評価試験＞得られたペレット触媒を評価
試験装置内にそれぞれ配置し、表３に示すモデルガスを
リッチ１分間−リーン４分間で切り換えながら、入りガ
ス温度 700℃で交互に７時間流す耐久試験を行った。<Evaluation Test> Each of the obtained pellet catalysts was placed in an evaluation test apparatus, and the model gas shown in Table 3 was switched between rich 1 minute and lean 4 minutes, and alternately for 7 hours at an inlet gas temperature of 700 ° C. A running durability test was performed.
【００６５】[0065]
【表３】 その後、耐久試験前の初期と耐久試験後のペレット触媒
について、上記のリーンモデルガス中にて、入りガス温
度 300℃における触媒入りガス中のNO濃度と触媒出ガス
中のNO濃度の差から、それぞれのNOx 浄化率を測定し
た。結果を表４に示す。[Table 3] Then, for the initial stage of the pellet catalyst after the durability test and the pellet catalyst after the durability test, in the above lean model gas, from the difference between the NO concentration in the catalyst-containing gas and the NO concentration in the catalyst-out gas at an inlet gas temperature of 300 ° C, It was measured each of the NO x purification rate. Table 4 shows the results.
【００６６】（実施例８）実施例７と同様にして、アル
ミナ粉末 150ｇにBaを 0.1モル担持してコア部粉末を調
製した。またトリイソプロポキシアルミニウム Al(OC3H
7)3 を Al2O3換算で50ｇとなるように混合溶解したこと
以外は実施例７と同様にして触媒担持層を形成した。つ
まり、コア部と触媒担持層の重量比をコア部：触媒担持
層＝３：１としたこと以外は実施例７と同様にして触媒
粉末を調製した。この触媒粉末 200ｇ当たり、Ptは２ｇ
複合担持され、Baは 0.1モル担持されている。そして実
施例７と同様に初期と耐久後のNOx 浄化率を測定し、結
果を表４に示す。Example 8 In the same manner as in Example 7, a core powder was prepared by supporting 0.1 mol of Ba on 150 g of alumina powder. In addition, triisopropoxy aluminum Al (OC 3 H
7) 3 was except that the mixture dissolved at a 50g in terms of Al 2 O 3 in the same manner as in Example 7 to form a catalyst supporting layer. That is, a catalyst powder was prepared in the same manner as in Example 7, except that the weight ratio of the core part to the catalyst supporting layer was set to core part: catalyst supporting layer = 3: 1. 2 g of Pt per 200 g of this catalyst powder
Complex is supported, and 0.1 mol of Ba is supported. And similarly measure the initial and the NO x purification ratio after durability as in Example 7, the results are shown in Table 4.
【００６７】（実施例９）実施例７と同様にして、アル
ミナ粉末 250ｇにBaを0.15モル担持してコア部粉末を調
製した。またトリイソプロポキシアルミニウム Al(OC3H
7)3 を Al2O3換算で50ｇとなるように混合溶解したこと
以外は実施例７と同様にして触媒担持層を形成した。つ
まり、コア部と触媒担持層の重量比をコア部：触媒担持
層＝５：１としたこと以外は実施例７と同様にして触媒
粉末を調製した。この触媒粉末200ｇ当たり、Ptは２ｇ
複合担持され、Baは 0.1モル担持されている。そして実
施例７と同様に初期と耐久後のNOx 浄化率を測定し、結
果を表４に示す。Example 9 In the same manner as in Example 7, a core powder was prepared by supporting 0.15 mol of Ba on 250 g of alumina powder. In addition, triisopropoxy aluminum Al (OC 3 H
7) 3 was except that the mixture dissolved at a 50g in terms of Al 2 O 3 in the same manner as in Example 7 to form a catalyst supporting layer. That is, a catalyst powder was prepared in the same manner as in Example 7, except that the weight ratio of the core portion to the catalyst supporting layer was set to 5: 1. 2 g of Pt per 200 g of this catalyst powder
Complex is supported, and 0.1 mol of Ba is supported. And similarly measure the initial and the NO x purification ratio after durability as in Example 7, the results are shown in Table 4.
【００６８】（実施例10）酢酸バリウムの代わりに酢酸
カリウムを所定量用い、実施例７と同様にしてアルミナ
粉末 150ｇに 0.1モルのＫを担持したコア部粉末を形成
した。またトリイソプロポキシアルミニウム Al(OC3H7)
3 を Al2O3換算で50ｇとなるように混合溶解したこと以
外は実施例７と同様にして触媒担持層を形成した。コア
部と触媒担持層の重量比は、コア部：触媒担持層＝３：
１である。触媒粉末 200ｇ当たり、Ptは２ｇ複合担持さ
れ、Ｋは 0.1モル担持されている。そして実施例７と同
様に初期と耐久後のNOx 浄化率を測定し、結果を表４に
示す。Example 10 A core powder was prepared in the same manner as in Example 7 except that a predetermined amount of potassium acetate was used instead of barium acetate, and 150 g of alumina powder carried 0.1 mol of K on alumina powder. Aluminum triisopropoxy Al (OC 3 H 7 )
3 was except that the mixture dissolved at a 50g in terms of Al 2 O 3 in the same manner as in Example 7 to form a catalyst supporting layer. The weight ratio of the core part to the catalyst supporting layer is as follows: core part: catalyst supporting layer = 3:
It is one. Per 200 g of the catalyst powder, 2 g of Pt is compositely supported and 0.1 mol of K is supported. And similarly measure the initial and the NO x purification ratio after durability as in Example 7, the results are shown in Table 4.
【００６９】（実施例11）アルミナ粉末の代わりに市販
のTiO2粉末（アナターゼ型、比表面積65m2 /g）150ｇを
用い、実施例７と同様にしてコア部粉末を調製した。コ
ア部粉末 150ｇに対してBaは 0.1モル担持された。また
トリイソプロポキシアルミニウム Al(OC 3H7)3 を Al2O3
換算で50ｇとなるように混合溶解したこと以外は実施例
１と同様にして触媒担持層を形成した。コア部と触媒担
持層の重量比は、コア部：触媒担持層＝３：１である。
この触媒粉末 200ｇ当たり、Ptは２ｇ複合担持され、Ba
は0.1モル担持されている。そして実施例７と同様に初
期と耐久後のNOx 浄化率を測定し、結果を表４に示す。Example 11 Commercially available instead of alumina powder
TiOTwoPowder (anatase type, specific surface area 65mTwo/ g) 150g
Using the same procedure as in Example 7, a core portion powder was prepared. Ko
0.1 mol of Ba was carried on 150 g of powder A. Also
Aluminum triisopropoxy Al (OC ThreeH7)Three The AlTwoOThree
Example except that it was mixed and dissolved to be 50 g in conversion
In the same manner as in 1, a catalyst supporting layer was formed. Core and catalyst
The weight ratio of the supporting layer is such that the core part: the catalyst supporting layer = 3: 1.
Per 200 g of this catalyst powder, 2 g of Pt was compositely supported and Ba
Is supported by 0.1 mol. Then, as in the seventh embodiment,
NO after period and endurancexThe purification rate was measured, and the results are shown in Table 4.
【００７０】（実施例12）アルミナ粉末の代わりに市販
のZrO2 粉末（比表面積30m2 /g） 150ｇを用い、実施例
７と同様にしてコア部粉末を調製した。コア部粉末 150
ｇに対してBaは 0.1モル担持された。またトリイソプロ
ポキシアルミニウム Al(OC3H7)3 を Al2O3換算で50ｇと
なるように混合溶解したこと以外は実施例７と同様にし
て触媒担持層を形成した。コア部と触媒担持層の重量比
は、コア部：触媒担持層＝３：１である。この触媒粉末
200ｇ当たり、Ptは２ｇ複合担持され、Baは 0.1モル担
持されている。そして実施例７と同様に初期と耐久後の
NOx 浄化率を測定し、結果を表４に示す。Example 12 A core powder was prepared in the same manner as in Example 7, except that 150 g of a commercially available ZrO 2 powder (specific surface area: 30 m 2 / g) was used instead of the alumina powder. Core powder 150
0.1 mol of Ba was supported per g. Further, a catalyst supporting layer was formed in the same manner as in Example 7, except that triisopropoxyaluminum Al (OC 3 H 7 ) 3 was mixed and dissolved so as to be 50 g in terms of Al 2 O 3 . The weight ratio of the core part to the catalyst supporting layer is such that core part: catalyst supporting layer = 3: 1. This catalyst powder
Per 200 g, 2 g of Pt is supported as a composite, and 0.1 mol of Ba is supported. And, as in Example 7, the initial
The NO x purification rate was measured, and the results are shown in Table 4.
【００７１】（比較例２）所定濃度のジニトロジアンミ
ン白金水溶液の所定量を、実施例７で用いたと同様の活
性アルミナ粉末 200ｇに含浸させ、 110℃で３時間乾燥
後、 500℃で２時間焼成してPtを担持した。Ptの担持量
は、アルミナ 200ｇに対して２ｇである。次に、得られ
たPt担持アルミナ粉末に所定濃度の酢酸バリウム水溶液
の所定量を含浸させ、 110℃で３時間乾燥後、 500℃で
２時間焼成しBaを担持して触媒粉末を調製した。Baは触
媒粉末 200ｇ当たり０．１モル担持された。Comparative Example 2 A predetermined amount of a dinitrodiammine platinum aqueous solution having a predetermined concentration was impregnated into 200 g of the same activated alumina powder as used in Example 7, dried at 110 ° C. for 3 hours, and calcined at 500 ° C. for 2 hours. To carry Pt. The supported amount of Pt is 2 g per 200 g of alumina. Next, the obtained Pt-supported alumina powder was impregnated with a predetermined amount of a barium acetate aqueous solution having a predetermined concentration, dried at 110 ° C. for 3 hours, and calcined at 500 ° C. for 2 hours to support Ba to prepare a catalyst powder. Ba was supported in an amount of 0.1 mol per 200 g of the catalyst powder.
【００７２】得られた触媒粉末を用いて実施例７と同様
にペレット触媒を調製し、同様に初期と耐久後のNOx 浄
化率を測定した。結果を表４に示す。 （参考例１）実施例７と同様にして、アルミナ粉末50ｇ
にBaを 0.1モル担持してコア部粉末を調製した。またト
リイソプロポキシアルミニウム Al(OC3H7)3 を Al2O3換
算で150ｇとなるように混合溶解したこと以外は実施例
７と同様にして触媒担持層を形成した。つまり、コア部
と触媒担持層の重量比をコア部：触媒担持層＝１：３と
したこと以外は実施例７と同様にして触媒粉末を調製し
た。この触媒粉末200ｇ当たり、Ptは２ｇ複合担持さ
れ、Baは 0.1モル担持されている。そして実施例７と同
様に初期と耐久後のNOx 浄化率を測定し、結果を表４に
示す。[0072] The resulting catalyst powder similarly using catalyst pellets prepared as in Example 7, was measured in the same manner beginning and the NO x purification ratio after endurance. Table 4 shows the results. (Reference Example 1) As in Example 7, 50 g of alumina powder
Was loaded with 0.1 mol of Ba to prepare a core powder. Further, a catalyst supporting layer was formed in the same manner as in Example 7, except that triisopropoxyaluminum Al (OC 3 H 7 ) 3 was mixed and dissolved so as to be 150 g in terms of Al 2 O 3 . That is, a catalyst powder was prepared in the same manner as in Example 7, except that the weight ratio of the core part to the catalyst supporting layer was set to core part: catalyst supporting layer = 1: 3. Per 200 g of the catalyst powder, 2 g of Pt is supported as a composite, and 0.1 mol of Ba is supported. And similarly measure the initial and the NO x purification ratio after durability as in Example 7, the results are shown in Table 4.
【００７３】（参考例２）実施例７と同様にして、アル
ミナ粉末 180ｇにBaを 0.1モル担持してコア部粉末を調
製した。またトリイソプロポキシアルミニウム Al(OC3H
7)3 を Al2O3換算で20ｇとなるように混合溶解したこと
以外は実施例７と同様にして触媒担持層を形成した。つ
まり、コア部と触媒担持層の重量比をコア部：触媒担持
層＝９：１としたこと以外は実施例７と同様にして触媒
粉末を調製した。この触媒粉末 200ｇ当たり、Ptは２ｇ
複合担持され、Baは 0.1モル担持されている。そして実
施例１と同様に初期と耐久後のNOx 浄化率を測定し、結
果を表４に示す。Reference Example 2 In the same manner as in Example 7, 180 g of alumina powder was loaded with 0.1 mol of Ba to prepare a core powder. In addition, triisopropoxy aluminum Al (OC 3 H
7) 3 was except that the mixture dissolved at a 20g in terms of Al 2 O 3 in the same manner as in Example 7 to form a catalyst supporting layer. That is, a catalyst powder was prepared in the same manner as in Example 7, except that the weight ratio of the core portion and the catalyst supporting layer was set to 9: 1. 2 g of Pt per 200 g of this catalyst powder
Complex is supported, and 0.1 mol of Ba is supported. And similarly measure the initial and the NO x purification ratio after durability as in Example 1. The results are shown in Table 4.
【００７４】[0074]
【表４】 （評価）従来の触媒である比較例２では、初期のNOx 浄
化率は比較的良好であるが、耐久後のNOx 浄化率の低下
が著しい。これに対し実施例７〜12の触媒では、NOx 浄
化率の低下度合いが小さく、耐久後も比較的高いNOx 浄
化率が維持されていることがわかる。これは、NOx 吸蔵
材をコア部に担持し、Ptを触媒担持層に担持したことに
よる効果であることが明らかであり、耐久時にPtがシン
タリングするのが抑制されたことによる効果と考えられ
る。[Table 4] (Evaluation) Comparative Example 2 is a conventional catalyst, the initial of the NO x purification rate is relatively good, the significant reduction of the NO x purification ratio after endurance. In the catalyst of Example 7-12 contrast, small degree of decrease of the NO x purification rate, it can be seen that after the endurance is relatively high the NO x purification rate is maintained. Idea which carries the the NO x storage material in the core section, Pt and it is clear that an effective due to the carried on the catalyst carrying layer, and the effect of Pt is to sintering is suppressed during endurance Can be
【００７５】一方、参考例１の触媒は、基本的には実施
例と同様の構成であるが、初期及び耐久後のNOx 浄化率
が低くなっている。これは、参考例１ではBaを含むコア
部が相対的に少なくなり、かつPtとの距離が離れすぎた
ために、NOx 吸蔵反応が充分進まず初期のNOx 浄化率が
低くなったものと考えられる。また耐久後のNOx 浄化率
の低下度合いが大きいのは、コア部とBaの反応による劣
化と考えられる。[0075] On the other hand, the catalyst in Reference Example 1, is basically the same as those of Example, NO x purification ratio after the initial and durability is low. This is because in Reference Example 1, the core portion containing Ba was relatively small, and the distance from Pt was too large, so that the NO x storage reaction did not proceed sufficiently and the initial NO x purification rate was low. Conceivable. Further, it is considered that the degree of decrease in the NO x purification rate after the durability is large is deterioration due to the reaction between the core portion and Ba.
【００７６】また参考例２の触媒も基本的には実施例と
同様の構成であるが、やはり初期及び耐久後のNOx 浄化
率が低くなっている。これは、参考例２ではPtを担持し
た粒子が相対的に少なくなり、NOの酸化反応とNOx 吸蔵
反応の両方が円滑に進行しなかったため初期のNOx 浄化
率が低くなったものと考えられる。また耐久後のNOx浄
化率の低下度合いが大きいのは、Ptのシンタリングによ
り劣化したものと考えられる。[0076] Although the catalyst basically of Reference Example 2 is the same as those of Example, the initial and the NO x purification ratio after durability it is also is low. This is considered that particles carrying Pt in Reference Example 2 is relatively reduced, the initial of the NO x purification rate because both did not proceed smoothly in the oxidation reaction and the NO x storage reaction of NO is lowered Can be Further, it is considered that the reason why the NO x purification rate after the endurance is large is the deterioration degree due to the sintering of Pt.
【００７７】なお本実施例では、アルミニウムアルコキ
シドの溶液中にコア部粉末を分散させてPt塩の水溶液を
添加することにより加水分解する方法を用いたが、イオ
ン交換水で加水分解した後、従来のように吸着担持法あ
るいは含浸担持法などによりPtを担持することもでき
る。この場合は、Ptはコア部にも一部担持されることと
なるが、表面の触媒担持層の寄与が大きいため実施例と
ほぼ同様の効果が得られることがわかっている。In this embodiment, the method of dispersing the core powder in a solution of aluminum alkoxide and adding an aqueous solution of a Pt salt to perform hydrolysis is used. As described above, Pt can be supported by an adsorption supporting method or an impregnating supporting method. In this case, Pt is also partially supported on the core portion, but it is known that almost the same effects as those of the example can be obtained because the contribution of the catalyst supporting layer on the surface is large.
【００７８】（実施例13）図３に本実施例の排ガス浄化
用触媒の概念的な断面図を示す。この排ガス浄化用触媒
は触媒粉末３の集合体よりなり、触媒粉末３はコア部30
と、コア部30表面に形成された触媒担持層31とから構成
されている。コア部30はK2O,TiO2及び Al2O3の複合酸化
物からなり、触媒担持層31はPtが複合化されたアルミナ
から構成されている。(Embodiment 13) FIG. 3 is a conceptual sectional view of an exhaust gas purifying catalyst of this embodiment. This exhaust gas purifying catalyst is composed of an aggregate of the catalyst powder 3, and the catalyst powder 3
And a catalyst supporting layer 31 formed on the surface of the core 30. The core 30 is made of a composite oxide of K 2 O, TiO 2 and Al 2 O 3 , and the catalyst support layer 31 is made of Pt-composited alumina.
【００７９】以下、この排ガス浄化用触媒の製造方法を
説明して構成の詳細な説明に代える。 ＜コア形成工程＞ステンレス容器に所定量のイソプロピ
ルアルコールを入れ、トリイソプロポキシアルミニウム
Al(OC3H7)3 を Al2O3換算で39.9ｇとなるように投入し
た。次に、酢酸カリウムを K2O換算で18.8ｇ、チタン酸
テトライソプロポキシド Ti(OC3H7)4 をTiO2換算で31.
3ｇとなるよう投入した。Hereinafter, the method for producing the exhaust gas purifying catalyst will be described, and the detailed description of the constitution will be replaced. <Core forming step> A predetermined amount of isopropyl alcohol is placed in a stainless steel container, and triisopropoxy aluminum is added.
Al (OC 3 H 7 ) 3 was introduced so as to become 39.9 g in terms of Al 2 O 3 . Then, 18.8 g of potassium acetate in K 2 O in terms of titanium tetra isopropoxide Ti (OC 3 H 7) 4 at terms of TiO 2 31.
It was charged to 3 g.
【００８０】この溶液は80℃に加熱され、攪拌・溶解
後、所定量のイオン交換水で加水分解され、ゾル−ゲル
化・乾燥・粉砕・焼成（ 500℃）工程を経てコア部粉末
を得た。コア部粉末は、K2O,TiO2及び Al2O3がモル比で
0.4:1:1の割合の組成の複合酸化物から構成されてい
る。 ＜担持層形成工程＞ステンレス容器に所定量のイソプロ
ピルアルコールを入れ、トリイソプロポキシアルミニウ
ム Al(OC3H7)3 を Al2O3換算で50ｇと、コア部粉末50ｇ
とを投入した。The solution is heated to 80 ° C., stirred and dissolved, hydrolyzed with a predetermined amount of ion-exchanged water, and subjected to a sol-gelation, drying, pulverization and firing (500 ° C.) process to obtain a core powder. Was. The core powder is composed of K 2 O, TiO 2 and Al 2 O 3 in a molar ratio.
It is composed of a composite oxide having a composition of 0.4: 1: 1. <Supporting layer forming step> A predetermined amount of isopropyl alcohol is put in a stainless steel container, and triisopropoxyaluminum Al (OC 3 H 7 ) 3 is 50 g in terms of Al 2 O 3 , and core powder 50 g.
And put in.
【００８１】次に、この溶液を攪拌しながら80℃に加熱
し、トリイソプロポキシアルミニウムを溶解した後、
1.1ｇのPtに相当するPt化合物（Ptアンミン水塩）を溶
解した水溶液で加水分解し、ゾル−ゲル化・乾燥・粉砕
・焼成（ 500℃）工程を経て、コア部表面にPt-Al2O3複
合体からなる触媒担持層を形成し、実施例13の触媒粉末
を得た。コア部と触媒担持層との比率は、重量比で１：
１である。 ＜触媒化＞得られた触媒粉末を定法でスラリー化し、直
径30mm、長さ50mmのコージェライト製モノリス担体にウ
ォッシュコートを施し 500℃で１時間焼成して、モノリ
ス触媒を調製した。コート量は担体容積１Ｌ当たり 180
ｇであり、Pt担持量は担体容積１Ｌ当たり２ｇとなる。 ＜試験＞得られたモノリス触媒は、表５に示すモデルガ
スによる耐久試験に供された。耐久試験は、入りガス温
度 700℃で、モノリス触媒にリーンガスとリッチガスを
4min/1minの割合で交互に合計４時間導入した。Next, the solution was heated to 80 ° C. with stirring to dissolve aluminum triisopropoxy.
Hydrolysis is carried out with an aqueous solution in which a Pt compound (Pt ammine water salt) corresponding to 1.1 g of Pt is dissolved, and through a sol-gelation, drying, pulverization and firing (500 ° C.) process, Pt-Al 2 A catalyst supporting layer made of an O 3 composite was formed, and a catalyst powder of Example 13 was obtained. The ratio between the core and the catalyst-supporting layer was 1: 1:
It is one. <Catalysis> The obtained catalyst powder was slurried by a standard method, a wash coat was applied to a cordierite monolith carrier having a diameter of 30 mm and a length of 50 mm, and calcined at 500 ° C. for 1 hour to prepare a monolith catalyst. The coating amount is 180 per liter of carrier volume.
g, and the amount of Pt carried is 2 g per liter of the carrier volume. <Test> The obtained monolith catalyst was subjected to a durability test using a model gas shown in Table 5. The endurance test was conducted at 700 ° C gas temperature, using lean gas and rich gas for the monolith catalyst.
It was introduced alternately at a rate of 4 min / 1 min for a total of 4 hours.
【００８２】耐久試験後のモノリス触媒について、表５
に示すモデルガスによりNOx 浄化率が測定された。NOx
浄化率の測定は、入りガス温度 300℃で、モノリス触媒
にリーンガスとリッチガスを 2min/2minの割合で交互に
導入し、リーン時のNOx 浄化率を測定した。結果を表６
に示す。Table 5 shows the results of the monolith catalyst after the durability test.
The NO x purification rate was measured using the model gas shown in FIG. NO x
Measurements of the purification rate at the gas temperature 300 ° C. entering the lean and rich gas monolithic catalyst introduced alternately at the rate of 2min / 2min, was measured the NO x purification rate of the lean. Table 6 shows the results
Shown in
【００８３】[0083]
【表５】 （実施例14）実施例13と同様に、イソプロピルアルコー
ル中に Al2O3換算で51.1ｇとなる量のトリイソプロポキ
シアルミニウム、 K2O換算で18.8ｇとなる量の酢酸カリ
ウム、TiO2換算で20ｇとなる量のチタンテトライソプロ
ポキシドを投入し、同様にしてK2O,TiO2及び Al2O3がモ
ル比で0.8:1:2の組成のコア部粉末を得た。[Table 5] Example 14 Similarly to Example 13, triisopropoxyaluminum in an amount of 51.1 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, and TiO 2 equivalent Then, titanium tetraisopropoxide was added in an amount of 20 g to obtain a core powder having a composition of K 2 O, TiO 2 and Al 2 O 3 in a molar ratio of 0.8: 1: 2 in the same manner.
【００８４】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. The NOx purification rate of the monolith catalyst after the durability test was measured in the same manner as in Example 13, and the results are shown in Table 6.
【００８５】（実施例15）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で59.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で18.8ｇとなる
量の酢酸カリウム、TiO2換算で11.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及び Al2O3がモル比で 1.4:1:4の組成のコア部粉末を得
た。(Example 15) As in Example 13, triisopropoxyaluminum in an amount of 59.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, Titanium tetraisopropoxide was added in an amount of 11.7 g in terms of TiO 2 , and K 2 O, TiO 2
And a core powder having a composition of Al 2 O 3 in a molar ratio of 1.4: 1: 4 was obtained.
【００８６】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst carrying layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【００８７】（実施例16）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で63ｇとなる量のトリイ
ソプロポキシアルミニウム、 K2O換算で18.8ｇとなる量
の酢酸カリウム、TiO2換算で 8.2ｇとなる量のチタンテ
トライソプロポキシドを投入し、同様にしてK2O,TiO2及
び Al2O3がモル比で 2:1:6の組成のコア部粉末を得た。Example 16 In the same manner as in Example 13, triisopropoxyaluminum in an amount of 63 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, TiO 2 Titanium tetraisopropoxide in an amount of 8.2 g in terms of 2 was added, and a core powder having a composition of K 2 O, TiO 2 and Al 2 O 3 in a molar ratio of 2: 1: 6 was similarly obtained. .
【００８８】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. The NOx purification rate of the monolith catalyst after the durability test was measured in the same manner as in Example 13, and the results are shown in Table 6.
【００８９】（実施例17）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で65.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で13.4ｇとなる
量の酢酸カリウム、TiO2換算で 5.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及びAl2O3がモル比で 2:1:9の組成のコア部粉末を得
た。Example 17 As in Example 13, triisopropoxyaluminum in an amount of 65.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 13.4 g in terms of K 2 O, Titanium tetraisopropoxide was added in an amount of 5.7 g in terms of TiO 2 , and K 2 O, TiO 2
A core powder having a composition of Al 2 O 3 in a molar ratio of 2: 1: 9 was obtained.
【００９０】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【００９１】（実施例18）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で66.8ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で10ｇとなる量
の酢酸カリウム、TiO2換算で 4.4ｇとなる量のチタンテ
トライソプロポキシドを投入し、同様にしてK2O,TiO2及
び Al2O3がモル比で 2:1:12の組成のコア部粉末を得
た。Example 18 As in Example 13, triisopropoxyaluminum in an amount of 66.8 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 10 g in terms of K 2 O, TiO 2 Titanium tetraisopropoxide was added in an amount of 4.4 g in terms of 2 to obtain a core powder having a composition of K2O, TiO2 and Al2O3 in a molar ratio of 2: 1: 12 in the same manner.
【００９２】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【００９３】（実施例19）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で59.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で18.8ｇとなる
量の酢酸カリウム、TiO2換算で11.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及び Al2O3がモル比で 1.4:1:4の組成のコア部粉末を得
た。(Example 19) As in Example 13, triisopropoxyaluminum in an amount of 59.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, Titanium tetraisopropoxide was added in an amount of 11.7 g in terms of TiO 2 , and K 2 O, TiO 2
And a core powder having a composition of Al 2 O 3 in a molar ratio of 1.4: 1: 4 was obtained.
【００９４】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：２である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 2 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【００９５】（実施例20）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で59.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で18.8ｇとなる
量の酢酸カリウム、TiO2換算で11.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及び Al2O3がモル比で 1.4:1:4の組成のコア部粉末を得
た。Example 20 In the same manner as in Example 13, triisopropoxyaluminum in an amount of 59.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, Titanium tetraisopropoxide was added in an amount of 11.7 g in terms of TiO2, and K 2 O, TiO 2
And a core powder having a composition of Al 2 O 3 in a molar ratio of 1.4: 1: 4 was obtained.
【００９６】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で２：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst carrying layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 2: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【００９７】（実施例21）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で59.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で18.8ｇとなる
量の酢酸カリウム、TiO2換算で11.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及び Al2O3がモル比で 1.4:1:4の組成のコア部粉末を得
た。Example 21 In the same manner as in Example 13, triisopropoxyaluminum in an amount of 59.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O , TiO 2 2 Titanium tetraisopropoxide in an amount of 11.7 g in terms of 2 was added, and K 2 O, TiO 2
And a core powder having a composition of Al 2 O 3 in a molar ratio of 1.4: 1: 4 was obtained.
【００９８】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で３：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 3: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【００９９】（実施例22）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で59.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で18.8ｇとなる
量の酢酸カリウム、TiO2換算で11.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及び Al2O3がモル比で 1.4:1:4の組成のコア部粉末を得
た。Example 22 As in Example 13, triisopropoxyaluminum in an amount of 59.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, Titanium tetraisopropoxide was added in an amount of 11.7 g in terms of TiO2, and K 2 O, TiO 2
And a core powder having a composition of Al 2 O 3 in a molar ratio of 1.4: 1: 4 was obtained.
【０１００】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で５：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst carrying layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 5: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【０１０１】（実施例23）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で59.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で18.8ｇとなる
量の酢酸カリウム、TiO2換算で11.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及び Al2O3がモル比で 1.4:1:4の組成のコア部粉末を得
た。Example 23 As in Example 13, triisopropoxyaluminum in an amount of 59.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, Titanium tetraisopropoxide was added in an amount of 11.7 g in terms of TiO 2 , and K 2 O, TiO 2
And a core powder having a composition of Al 2 O 3 in a molar ratio of 1.4: 1: 4 was obtained.
【０１０２】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で７：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 7: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【０１０３】（実施例24）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で61.0ｇとなる量のトリ
イソプロポキシアルミニウムと、TiO2換算で12ｇとなる
量のチタンテトライソプロポキシドを投入し、同様にし
てTiO2及び Al2O3がモル比で１：４の組成の粉末を得
た。Example 24 In the same manner as in Example 13, triisopropoxyaluminum in an amount of 61.0 g in terms of Al 2 O 3 and titanium tetraisopropoxy in an amount of 12 g in terms of TiO 2 were used in isopropyl alcohol. In the same manner, powder having a composition of TiO 2 and Al 2 O 3 in a molar ratio of 1: 4 was obtained.
【０１０４】この粉末71.2ｇを、 0.2モルの酢酸カリウ
ムを溶解した水溶液中に投入し、蒸発乾固させて 0.2モ
ルのＫを担持したコア部粉末を調製した。このコア部粉
末を用い、実施例13と同様にしてPt-Al2O3からなる触媒
担持層を形成した。コア部と触媒担持層との比率は、重
量比で１：１である。得られた触媒粉末を用いて実施例
13と同様にモノリス触媒を調製し、同様にして耐久試験
を行った。そして耐久試験後のモノリス触媒について、
実施例13と同様にしてNOx 浄化率を測定し、結果を表６
に示す。71.2 g of this powder was put into an aqueous solution in which 0.2 mol of potassium acetate was dissolved, and evaporated to dryness to prepare a core powder supporting 0.2 mol of K. Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Example using the obtained catalyst powder
A monolith catalyst was prepared in the same manner as in 13, and a durability test was performed in the same manner. And about the monolith catalyst after the durability test,
The NO x purification rate was measured in the same manner as in Example 13, and the results were shown in Table 6.
Shown in
【０１０５】（実施例25）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で71.2ｇとなる量のトリ
イソプロポキシアルミニウムと、 K2O換算で10.9ｇとな
る量の酢酸カリウムを投入し、同様にしてK2O及びAl2O3
がモル比で１：６の組成のコア部粉末を得た。Example 25 Similarly to Example 13, triisopropoxyaluminum in an amount of 71.2 g in terms of Al 2 O 3 in isopropyl alcohol and potassium acetate in an amount of 10.9 g in terms of K 2 O And K 2 O and Al 2 O 3
Was obtained in a molar ratio of 1: 6.
【０１０６】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【０１０７】（実施例26）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で60ｇとなる量のトリイ
ソプロポキシアルミニウムと、 BaO換算で30ｇとなる量
のジイソプロポキシバリウムを投入し、同様にしてBaO
及びAl2O3がモル比で１：３の組成のコア部粉末を得
た。Example 26 As in Example 13, triisopropoxyaluminum in an amount of 60 g in terms of Al 2 O 3 and diisopropoxybarium in an amount of 30 g in terms of BaO were introduced into isopropyl alcohol. And BaO in the same way
And a core powder having a composition of Al 2 O 3 in a molar ratio of 1: 3 was obtained.
【０１０８】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【０１０９】（実施例27）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で55.2ｇとなる量のトリ
イソプロポキシアルミニウム、 BaO換算で27.6ｇとなる
量のジイソプロポキシバリウム、TiO2換算で 7.2ｇとな
る量のチタンテトライソプロポキシドを投入し、同様に
してBaO,TiO2及び Al2O3がモル比で 1:0.5:3の組成のコ
ア部粉末を得た。Example 27 As in Example 13, triisopropoxyaluminum in an amount of 55.2 g in terms of Al 2 O 3 in isopropyl alcohol, diisopropoxybarium in an amount of 27.6 g in terms of BaO, Titanium tetraisopropoxide was added in an amount of 7.2 g in terms of TiO 2 , and similarly a core powder having a composition of BaO, TiO 2 and Al 2 O 3 in a molar ratio of 1: 0.5: 3 was obtained.
【０１１０】このコア部粉末を用い、実施例13と同様に
してPt-Al2O3からなる触媒担持層を形成した。コア部と
触媒担持層との比率は、重量比で１：１である。得られ
た触媒粉末を用いて実施例13と同様にモノリス触媒を調
製し、同様にして耐久試験を行った。そして耐久試験後
のモノリス触媒について、実施例13と同様にしてNOx 浄
化率を測定し、結果を表６に示す。Using this core powder, a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【０１１１】（実施例28）市販の活性アルミナ粉末（平
均粒径10μｍ）71.2ｇを、 0.2モルの酢酸カリウムを溶
解した水溶液中に投入し、蒸発乾固させて 0.2モルのＫ
を担持した。次にこの K-Al2O3粉末をコア部粉末とし、
実施例13と同様にしてPt-Al2O3からなる触媒担持層を形
成した。コア部と触媒担持層との比率は、重量比で１：
１である。Example 28 71.2 g of commercially available activated alumina powder (average particle size: 10 μm) was put into an aqueous solution in which 0.2 mol of potassium acetate was dissolved, and evaporated to dryness to obtain 0.2 mol of K
Was carried. Next, this K-Al 2 O 3 powder was used as core powder,
A catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst-supporting layer was 1: 1:
It is one.
【０１１２】得られた触媒粉末を用いて実施例13と同様
にモノリス触媒を調製し、同様にして耐久試験を行っ
た。そして耐久試験後のモノリス触媒について、実施例
13と同様にしてNOx 浄化率を測定し、結果を表６に示
す。（実施例29）市販の活性アルミナ粉末（平均粒径10
μｍ）とチタニア粉末（平均粒径３μｍ）とを、TiO2:A
lO3=１：４のモル比で混合した。この混合粉末を 0.2モ
ルの酢酸カリウムを溶解した水溶液中に投入し、蒸発乾
固させて 0.2モルのＫを担持した。Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. For the monolith catalyst after the durability test,
The NO x purification rate was measured in the same manner as in Example 13, and the results are shown in Table 6. (Example 29) Commercially available activated alumina powder (average particle size of 10
and [mu] m) and titania powder (average particle size 3μm), TiO 2: A
lO 3 = 1: were mixed in a molar ratio of 4. This mixed powder was put into an aqueous solution in which 0.2 mol of potassium acetate was dissolved, and evaporated to dryness to carry 0.2 mol of K.
【０１１３】得られた粉末をコア部と粉末とし、実施例
13と同様にしてPt-Al2O3からなる触媒担持層を形成し
た。コア部と触媒担持層との比率は、重量比で１：１で
ある。得られた触媒粉末を用いて実施例13と同様にモノ
リス触媒を調製し、同様にして耐久試験を行った。そし
て耐久試験後のモノリス触媒について、実施例13と同様
にしてNOx 浄化率を測定し、結果を表６に示す。The obtained powder was used as a core part and a powder.
In the same manner as in 13, a catalyst supporting layer made of Pt—Al 2 O 3 was formed. The ratio between the core and the catalyst supporting layer is 1: 1 by weight. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【０１１４】（実施例30）実施例13と同様に、イソプロ
ピルアルコール中に Al2O3換算で59.5ｇとなる量のトリ
イソプロポキシアルミニウム、 K2O換算で18.8ｇとなる
量の酢酸カリウム、TiO2換算で11.7ｇとなる量のチタン
テトライソプロポキシドを投入し、同様にしてK2O,TiO2
及び Al2O3がモル比で 1.4:1:4の組成のコア部粉末を得
た。Example 30 As in Example 13, triisopropoxyaluminum in an amount of 59.5 g in terms of Al 2 O 3 in isopropyl alcohol, potassium acetate in an amount of 18.8 g in terms of K 2 O, Titanium tetraisopropoxide was added in an amount of 11.7 g in terms of TiO 2 , and K 2 O, TiO 2
And a core powder having a composition of Al2O3 in a molar ratio of 1.4: 1: 4 was obtained.
【０１１５】このコア部粉末を、 Al2O3換算で50ｇとな
る量のトリイソプロポキシアルミニウムを溶解したイソ
プロピルアルコール中に50ｇ投入して、80℃で攪拌しな
がらイオン交換水で加水分解し、ゾル−ゲル化・乾燥・
粉砕・焼成工程を経て、コア部表面に Al2O3からなる担
持層を形成した。コア部と担持層との比率は、重量比で
１：１である。50 g of the core powder was put into isopropyl alcohol in which triisopropoxyaluminum was dissolved in an amount of 50 g in terms of Al 2 O 3 and hydrolyzed with ion-exchanged water while stirring at 80 ° C. Sol-gelation, drying,
After the pulverization and firing steps, a support layer made of Al 2 O 3 was formed on the core surface. The ratio between the core and the carrier layer is 1: 1 by weight.
【０１１６】次に、担持層が形成されたコア部粉末をジ
ニトロジアンミン白金水溶液に浸漬し、引き上げた後乾
燥・焼成して、 1.1重量％のPtが担持された触媒粉末を
得た。得られた触媒粉末を用いて実施例13と同様にモノ
リス触媒を調製し、同様にして耐久試験を行った。そし
て耐久試験後のモノリス触媒について、実施例13と同様
にしてNOx 浄化率を測定し、結果を表６に示す。Next, the core portion powder on which the support layer was formed was immersed in an aqueous solution of dinitrodiammine platinum, pulled up, dried and calcined to obtain a catalyst powder carrying 1.1% by weight of Pt. Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. And for monolithic catalyst after the durability test, measured the NO x purification rate in the same manner as in Example 13, the results are shown in Table 6.
【０１１７】（実施例31）市販の活性アルミナ粉末（平
均粒径10μｍ）60ｇを、 0.2モルの酢酸バリウムを溶解
した水溶液中に投入し、蒸発乾固させて 0.2モルのBaを
担持した。次にこのBa-Al2O3粉末をコア部粉末とし、実
施例13と同様にしてPt-Al2O3からなる触媒担持層を形成
した。コア部と触媒担持層との比率は、重量比で１：１
である。Example 31 60 g of commercially available activated alumina powder (average particle size: 10 μm) was put into an aqueous solution in which 0.2 mol of barium acetate was dissolved, and evaporated to dryness to carry 0.2 mol of Ba. Next, this Ba-Al 2 O 3 powder was used as a core portion powder, and a catalyst supporting layer made of Pt—Al 2 O 3 was formed in the same manner as in Example 13. The ratio between the core and the catalyst supporting layer was 1: 1 by weight.
It is.
【０１１８】得られた触媒粉末を用いて実施例13と同様
にモノリス触媒を調製し、同様にして耐久試験を行っ
た。そして耐久試験後のモノリス触媒について、実施例
13と同様にしてNOx 浄化率を測定し、結果を表６に示
す。（評価）Using the obtained catalyst powder, a monolith catalyst was prepared in the same manner as in Example 13, and a durability test was performed in the same manner. For the monolith catalyst after the durability test,
The NO x purification rate was measured in the same manner as in Example 13, and the results are shown in Table 6. (Evaluation)
【０１１９】[0119]
【表６】 [Table 6]
【０１２０】実施例13〜18は、コア部にいずれもK2O,Ti
O2,Al2O3を複合化し、触媒担持層にPtを複合化した Al2
O3を用いたものであるが、TiO2/Al2O3比と耐久性の関係
が伺える。すなわち、コア部にTiO2を含まない実施例28
に比べていずれも高いNOx 浄化率を示し、TiO2の複合化
が有効であることが明らかである。またTiO2/Al2O3比が
小さい実施例13、及びTiO2/Al2O3比が大きな実施例18で
は、TiO2/Al2O3比が１：４あるいは１：６の実施例15〜
16に比べてNOx 浄化率が比較的低い。これは、TiO2が少
ないと複合化した効果が小さく、TiO2が多すぎると耐熱
性が低下するためと考えられる。In Examples 13 to 18, K 2 O, Ti
The O 2, Al 2 O 3 and composite, Al 2 the Pt in the catalyst carrying layer complexed
Although O 3 was used, the relationship between the TiO 2 / Al 2 O 3 ratio and the durability can be seen. That is, Example 28 in which the core portion did not contain TiO 2
All show a higher NO x purification rate than the above, and it is clear that the compounding of TiO 2 is effective. Also the TiO 2 / Al2O 3 ratio is small in Example 13, and TiO 2 / Al 2 O 3 ratio is large Example 18, TiO 2 / Al 2 O 3 ratio of 1: 4 or 1: 6 Example 15 of
It is relatively low the NO x purification rate compared to 16. This complexed with effect as TiO 2 is small is small, when the TiO 2 is too large heat resistance is considered to decrease.
【０１２１】実施例15及び実施例19〜23においては、コ
ア部と触媒担持層の比率と耐久性の関係が伺える。すな
わちコア部／触媒担持層比が２：１あるいは３：１の実
施例20〜21でNOx 浄化率はピークを示し、このあたりの
比率が最適であることがわかる。実施例15及び実施例19
〜23においては、コア部はK2O,TiO2,Al2O3が同一比率で
複合化されたものであるので、コア部の比率が大きくな
るとNOx 吸蔵材（Ｋ）の量も増大するため、その影響に
よりPtにシンタリングが生じたことが考えられる。ま
た、コア部の比率が大きくなり過ぎると、Ptの担持密度
が高くなりすぎてシンタリングし易いことも原因と考え
られる。そしてコア部の比率が少ない場合には、Ｋが不
足するだけでなく、触媒担持層が厚くなり過ぎてPtが A
l2O3に埋没し、Ptの露出面積が低下したために耐久性が
低下したものと考えられる。In Examples 15 and 19 to 23, the relationship between the ratio of the core portion to the catalyst supporting layer and the durability can be seen. Or core portion / catalyst supporting layer ratio of 2: 1 or 3: NO x purification rate in the first embodiment 20 to 21 indicates a peak, it can be seen that the ratio per this is optimal. Example 15 and Example 19
In the case of ~ 23, the core portion is a composite of K 2 O, TiO 2 , and Al 2 O 3 at the same ratio. Therefore, as the ratio of the core portion increases, the amount of the NO x occluding material (K) also increases. Therefore, it is considered that sintering has occurred in Pt due to the influence. It is also considered that if the ratio of the core portion is too large, the carrying density of Pt becomes too high and sintering is easy. When the ratio of the core portion is small, not only K is insufficient but also the catalyst supporting layer becomes too thick and Pt becomes A
It is conceivable that durability was lowered due to buried in l 2 O 3 and the exposed area of Pt was reduced.
【０１２２】そして実施例24と実施例29の比較より、コ
ア部において、TiO2と Al2O3を物理的に混合するよりも
複合酸化物とした方が耐久性が向上することがわかる。
また実施例25と実施例28の比較より、Ｋはコア部に担持
されるよりも複合化された方が耐久性が向上することも
わかる。この原因は、Ｋを担持した場合にはコア部表面
にＫが偏析するが、複合化することによりＫは均一に高
分散されることによるものと考えられる。From a comparison between Example 24 and Example 29, it can be seen that the durability is improved by using a composite oxide in the core portion rather than by physically mixing TiO 2 and Al 2 O 3 .
Further, from a comparison between Example 25 and Example 28, it can be seen that the durability is improved when K is combined as compared with the case where K is carried on the core portion. It is considered that the cause is that K is segregated on the surface of the core when K is carried, but K is uniformly and highly dispersed by the compounding.
【０１２３】また実施例30では、NOx 吸蔵材であるＫが
複合化されているためコア部の構成としては好ましい
が、触媒担持層ではPtが吸着担持されている。そのため
Ptは Al2O3表面に高密度で担持されて分散性が低くなっ
たと考えられ、触媒担持層をPt-Al2O3複合体とした実施
例15に比べてNOx 浄化率が大きく低下している。なお、
実施例26〜27では、NOx 吸蔵材としてBaを用いている
が、Ｋの場合と同様に耐久性が向上していることがわか
る。しかしBaの場合には、理由は不明であるが、コア部
のTiO2の有無に関わらず耐久性の差はみられなかった。Further, in Example 30, since the NO x storage material K is compounded, the core portion is preferable, but Pt is adsorbed and supported on the catalyst supporting layer. for that reason
It is considered that Pt was supported on the Al 2 O 3 surface at high density and the dispersibility was lowered, and the NO x purification rate was significantly reduced compared to Example 15 in which the catalyst supporting layer was a Pt-Al 2 O 3 composite. doing. In addition,
In Examples 26 and 27, Ba was used as the NO x storage material, but it can be seen that the durability was improved as in the case of K. However, in the case of Ba, although the reason is unknown, there was no difference in durability regardless of the presence or absence of TiO 2 in the core.
【０１２４】[0124]
【発明の効果】すなわち本発明の排ガス浄化用触媒によ
れば、NOの酸化によるNOx の生成と、そのNOx のNOx 吸
蔵材への吸蔵、及びNOx 吸蔵材から放出されたNOx の還
元とが円滑に進行し、リーン雰囲気及びストイキ〜リー
ン雰囲気において高いNOx 浄化性能を両立させることが
できる。したがってリーンバーンエンジンからの排ガス
であってもNOx を効率よく還元除去することができ、か
つ耐久性に優れているため高いNOx 浄化性能を長期間維
持することができる。According to the exhaust gas purifying catalyst of the Effect of the Invention] The present invention, the generation of the NO x due to oxidation of NO, the NO adsorption to the NO x storage material of x, and NO x storage material NO x released from and reduction proceeds smoothly, it is possible to achieve both high the NO x purification performance in a lean atmosphere and the stoichiometric-lean atmosphere. Thus even the exhaust gas from a lean burn engine can be efficiently reduce and remove NO x, and it is possible to maintain high the NO x purification performance long time because of its excellent durability.
【０１２５】さらに本発明の排ガス浄化用触媒の製造方
法によれば、NOx 吸蔵元素と第１の金属とが原子レベル
で高分散したコア部粉末を容易かつ確実に形成すること
ができ、かつ貴金属と第２の金属とが原子レベルで高分
散した触媒担持層をコア部粉末表面に容易かつ確実に形
成することができるので、上記した本発明の排ガス浄化
用触媒を容易に安定して製造することができる。Further, according to the method for producing an exhaust gas purifying catalyst of the present invention, it is possible to easily and reliably form a core powder in which the NO x occluding element and the first metal are highly dispersed at the atomic level, and Since the catalyst supporting layer in which the noble metal and the second metal are highly dispersed at the atomic level can be easily and reliably formed on the surface of the core powder, the above-described exhaust gas purifying catalyst of the present invention can be easily and stably manufactured. can do.
【図１】本発明の一実施例の排ガス浄化用触媒の模式的
断面図である。FIG. 1 is a schematic sectional view of an exhaust gas purifying catalyst according to one embodiment of the present invention.
【図２】本発明の第７実施例の排ガス浄化用触媒の模式
的断面図である。FIG. 2 is a schematic sectional view of an exhaust gas purifying catalyst according to a seventh embodiment of the present invention.
【図３】本発明の第13実施例の排ガス浄化用触媒の模式
的断面図である。FIG. 3 is a schematic sectional view of an exhaust gas purifying catalyst according to a thirteenth embodiment of the present invention.
１：触媒粉末 10：コア部 11：アルミナ層
（触媒担持層）1: catalyst powder 10: core 11: alumina layer (catalyst supporting layer)
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｂ０１Ｊ 23/48 Ｂ０１Ｊ 33/00 Ｃ 23/89 ＺＡＢ 35/02 Ｐ 33/00 Ｂ０１Ｄ 53/36 ＺＡＢ 35/02 １０２Ａ １０２Ｈ １０４Ａ ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI B01J 23/48 B01J 33/00 C 23/89 ZAB 35/02 P 33/00 B01D 53/36 ZAB 35/02 102A 102H 104A
Claims (8)
吸蔵材とよりなるコア部と、第２担体と該第２担体に含
まれた触媒貴金属とよりなり該コア部表面に形成された
触媒担持層と、からなることを特徴とする排ガス浄化用
触媒。1. A first carrier and NO x contained in the first carrier.
An exhaust gas purifying catalyst comprising: a core portion made of an occluding material; a second carrier; and a catalyst supporting layer made of a catalyst noble metal contained in the second carrier and formed on the surface of the core portion. .
でコア部：触媒担持層＝１：２〜８：１となるように形
成されていることを特徴とする請求項１に記載の排ガス
浄化用触媒。2. The method according to claim 1, wherein the core part and the catalyst supporting layer are formed such that the weight ratio of the core part and the catalyst supporting layer is 1: 2 to 8: 1. Exhaust gas purification catalyst.
カリ土類金属の少なくとも一方から選ばれ、前記第２担
体は少なくともアルミナを含む金属酸化物であることを
特徴とする請求項１に記載の排ガス浄化用触媒。3. The method according to claim 1, wherein the NO x storage material is selected from at least one of an alkali metal and an alkaline earth metal, and the second carrier is a metal oxide containing at least alumina. Exhaust gas purification catalyst.
合酸化物からなり、モル比でTiO2/Al2O3=1/2〜1/9 であ
ることを特徴とする請求項１に記載の排ガス浄化用触
媒。4. The method according to claim 1, wherein the first carrier is composed of a composite oxide of alumina and titania, and has a molar ratio of TiO 2 / Al 2 O 3 = 1/2 to 1/9. Exhaust gas purification catalyst.
されていることを特徴とする請求項１に記載の排ガス浄
化用触媒。5. The exhaust gas purifying catalyst according to claim 1, wherein the catalytic noble metal is compounded with the second carrier.
酸化物を構成していることを特徴とする請求項１〜５に
記載の排ガス浄化用触媒。Wherein said first carrier and said the NO x storage material catalyst for purification of exhaust gas according to claim 1, characterized in that constituting the composite oxide.
なくとも一方から選ばれるNOx 吸蔵元素の塩と第１の金
属のアルコキシドとを混合して溶液とし、加水分解後焼
成することによりNOx 吸蔵元素と該第１の金属との複合
酸化物よりなるコア部粉末を形成するコア形成工程と、 第２の金属のアルコキシドと貴金属イオンを含む溶液と
該コア部粉末とを混合し、加水分解後焼成することで該
コア部粉末表面に該貴金属と該第２の金属とが複合化し
た触媒担持層を形成する担持層形成工程と、よりなるこ
とを特徴とする排ガス浄化用触媒の製造方法。7. the alkali metal and solution by mixing a salt of the NO x storage element selected from at least one alkoxide of the first metal alkaline earth metal, the NO x storage element by baking after hydrolysis Forming a core part powder comprising a composite oxide of the second metal and the first metal; mixing a solution containing an alkoxide of a second metal and a noble metal ion with the core part powder; A forming step of forming a catalyst supporting layer in which the noble metal and the second metal are composited on the surface of the core portion powder, thereby producing a catalyst for exhaust gas purification.
前記第２の金属のアルコキシドとを含む溶液に前記貴金
属イオンを含む水溶液を添加して加水分解することを特
徴とする請求項７に記載の排ガス浄化用触媒の製造方
法。8. The method according to claim 7, wherein in the supporting layer forming step, an aqueous solution containing the noble metal ion is added to a solution containing the core portion powder and the alkoxide of the second metal, followed by hydrolysis. A method for producing the exhaust gas purifying catalyst according to the above.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27764997A JP3640130B2 (en) | 1996-11-14 | 1997-10-09 | Exhaust gas purification catalyst and method for producing the same |
| US08/969,044 US6025297A (en) | 1996-11-14 | 1997-11-12 | Catalyst for purifying exhaust gas and process for producing the same |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30318296 | 1996-11-14 | ||
| JP8-303182 | 1997-01-17 | ||
| JP657297 | 1997-01-17 | ||
| JP9-6572 | 1997-01-17 | ||
| JP27764997A JP3640130B2 (en) | 1996-11-14 | 1997-10-09 | Exhaust gas purification catalyst and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10258232A true JPH10258232A (en) | 1998-09-29 |
| JP3640130B2 JP3640130B2 (en) | 2005-04-20 |
Family
ID=27277224
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|---|---|---|---|
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| Country | Link |
|---|---|
| JP (1) | JP3640130B2 (en) |
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| JP2000342967A (en) * | 1999-03-31 | 2000-12-12 | Toyota Motor Corp | Catalyst for purifying exhaust gas, its production, and method for purifying exhaust gas |
| FR2799665A1 (en) * | 1999-10-15 | 2001-04-20 | Toyota Motor Co Ltd | Catalyst, for exhaust gas purification, includes inorganic oxide layer containing noble and transition metals to protect nitrogen oxide absorber from poisoning by sulfur oxides |
| JP2002191989A (en) * | 2000-10-16 | 2002-07-10 | Toyota Motor Corp | Catalyst for cleaning exhaust gas and method for manufacturing the same |
| JP2004321847A (en) * | 2003-04-21 | 2004-11-18 | Toyota Central Res & Dev Lab Inc | Catalyst carrier, its production method, catalyst, and method for cleaning exhaust gas |
| JP2006518276A (en) * | 2003-01-31 | 2006-08-10 | エンゲルハード・コーポレーシヨン | Layered catalyst composite and method of using the same |
| US7220702B2 (en) | 2001-02-19 | 2007-05-22 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification catalyst |
| US7399729B2 (en) | 2003-12-22 | 2008-07-15 | General Electric Company | Catalyst system for the reduction of NOx |
| US7745371B2 (en) | 2004-03-09 | 2010-06-29 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying catalyst, metal oxide particle and production process thereof |
| WO2010146458A1 (en) * | 2009-06-17 | 2010-12-23 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying catalyst |
| US7989387B2 (en) | 2004-04-27 | 2011-08-02 | Toyota Jidosha Kabushiki Kaisha | Process for producing metal oxide particle and exhaust gas purifying catalyst |
| US8026193B2 (en) | 2004-04-27 | 2011-09-27 | Toyota Jidosha Kabushiki Kaisha | Metal oxide particle, production process thereof and exhaust gas purifying catalyst |
| US8293677B2 (en) | 2007-05-23 | 2012-10-23 | Toyota Jidosha Kabushiki Kaisha | Core-shell structure, process for its production, and exhaust gas purification catalyst comprising core-shell structure |
-
1997
- 1997-10-09 JP JP27764997A patent/JP3640130B2/en not_active Expired - Lifetime
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000342967A (en) * | 1999-03-31 | 2000-12-12 | Toyota Motor Corp | Catalyst for purifying exhaust gas, its production, and method for purifying exhaust gas |
| FR2799665A1 (en) * | 1999-10-15 | 2001-04-20 | Toyota Motor Co Ltd | Catalyst, for exhaust gas purification, includes inorganic oxide layer containing noble and transition metals to protect nitrogen oxide absorber from poisoning by sulfur oxides |
| JP2002191989A (en) * | 2000-10-16 | 2002-07-10 | Toyota Motor Corp | Catalyst for cleaning exhaust gas and method for manufacturing the same |
| US7229947B2 (en) | 2001-02-19 | 2007-06-12 | Toyota Jidosha Kabushiki Kaisha | Catalyst for hydrogen generation and catalyst for purifying of exhaust gas |
| US7220702B2 (en) | 2001-02-19 | 2007-05-22 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification catalyst |
| JP2006518276A (en) * | 2003-01-31 | 2006-08-10 | エンゲルハード・コーポレーシヨン | Layered catalyst composite and method of using the same |
| JP2004321847A (en) * | 2003-04-21 | 2004-11-18 | Toyota Central Res & Dev Lab Inc | Catalyst carrier, its production method, catalyst, and method for cleaning exhaust gas |
| US7399729B2 (en) | 2003-12-22 | 2008-07-15 | General Electric Company | Catalyst system for the reduction of NOx |
| US7745371B2 (en) | 2004-03-09 | 2010-06-29 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying catalyst, metal oxide particle and production process thereof |
| US7989387B2 (en) | 2004-04-27 | 2011-08-02 | Toyota Jidosha Kabushiki Kaisha | Process for producing metal oxide particle and exhaust gas purifying catalyst |
| US8026193B2 (en) | 2004-04-27 | 2011-09-27 | Toyota Jidosha Kabushiki Kaisha | Metal oxide particle, production process thereof and exhaust gas purifying catalyst |
| US8293677B2 (en) | 2007-05-23 | 2012-10-23 | Toyota Jidosha Kabushiki Kaisha | Core-shell structure, process for its production, and exhaust gas purification catalyst comprising core-shell structure |
| WO2010146458A1 (en) * | 2009-06-17 | 2010-12-23 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying catalyst |
| US9421535B2 (en) | 2009-06-17 | 2016-08-23 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying catalyst |
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