JP6608090B1 - Exhaust gas purification catalyst - Google Patents
Exhaust gas purification catalyst Download PDFInfo
- Publication number
- JP6608090B1 JP6608090B1 JP2019140093A JP2019140093A JP6608090B1 JP 6608090 B1 JP6608090 B1 JP 6608090B1 JP 2019140093 A JP2019140093 A JP 2019140093A JP 2019140093 A JP2019140093 A JP 2019140093A JP 6608090 B1 JP6608090 B1 JP 6608090B1
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- pore diameter
- partition wall
- catalyst
- catalyst 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.)
- Active
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 279
- 238000000746 purification Methods 0.000 title claims abstract description 74
- 239000011148 porous material Substances 0.000 claims abstract description 233
- 238000005192 partition Methods 0.000 claims abstract description 127
- 239000000758 substrate Substances 0.000 claims abstract description 59
- 238000009826 distribution Methods 0.000 claims abstract description 35
- 239000002002 slurry Substances 0.000 claims description 66
- 239000003502 gasoline Substances 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 8
- 238000002360 preparation method Methods 0.000 claims description 6
- 238000002485 combustion reaction Methods 0.000 abstract description 11
- 239000007789 gas Substances 0.000 description 140
- 239000000843 powder Substances 0.000 description 57
- 239000000463 material Substances 0.000 description 42
- 239000013618 particulate matter Substances 0.000 description 37
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 36
- 239000004071 soot Substances 0.000 description 36
- 239000002245 particle Substances 0.000 description 34
- 229910052751 metal Inorganic materials 0.000 description 29
- 239000002184 metal Substances 0.000 description 29
- 238000000034 method Methods 0.000 description 24
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 23
- 238000000576 coating method Methods 0.000 description 22
- 238000010304 firing Methods 0.000 description 22
- 239000011248 coating agent Substances 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 17
- 239000002131 composite material Substances 0.000 description 17
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 15
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 13
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 13
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 13
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 11
- 230000003197 catalytic effect Effects 0.000 description 11
- 239000001301 oxygen Substances 0.000 description 11
- 229910052760 oxygen Inorganic materials 0.000 description 11
- 239000010948 rhodium Substances 0.000 description 11
- 230000033228 biological regulation Effects 0.000 description 10
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 9
- 229910002091 carbon monoxide Inorganic materials 0.000 description 9
- 239000000446 fuel Substances 0.000 description 9
- 239000000243 solution Substances 0.000 description 9
- 239000007864 aqueous solution Substances 0.000 description 7
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 7
- 229910052703 rhodium Inorganic materials 0.000 description 7
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 229930195733 hydrocarbon Natural products 0.000 description 6
- 150000002430 hydrocarbons Chemical class 0.000 description 6
- 150000002739 metals Chemical class 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 230000010718 Oxidation Activity Effects 0.000 description 5
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 5
- 229910052753 mercury Inorganic materials 0.000 description 5
- 229910052763 palladium Inorganic materials 0.000 description 5
- 229910052697 platinum Inorganic materials 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 230000010757 Reduction Activity Effects 0.000 description 4
- ZUDYPQRUOYEARG-UHFFFAOYSA-L barium(2+);dihydroxide;octahydrate Chemical compound O.O.O.O.O.O.O.O.[OH-].[OH-].[Ba+2] ZUDYPQRUOYEARG-UHFFFAOYSA-L 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- 239000002923 metal particle Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000011232 storage material Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 239000001099 ammonium carbonate Substances 0.000 description 3
- 235000012501 ammonium carbonate Nutrition 0.000 description 3
- 230000001186 cumulative effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
- 239000003002 pH adjusting agent Substances 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000001629 suppression Effects 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 229910010413 TiO 2 Inorganic materials 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 229910000420 cerium oxide Inorganic materials 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000003779 heat-resistant material Substances 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 150000002484 inorganic compounds Chemical class 0.000 description 2
- 229910010272 inorganic material Inorganic materials 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 2
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 description 2
- 229910052762 osmium Inorganic materials 0.000 description 2
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 2
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- -1 platinum group metals Chemical class 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 229910052707 ruthenium Inorganic materials 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 239000006104 solid solution Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 2
- 229910001928 zirconium oxide Inorganic materials 0.000 description 2
- 229910000505 Al2TiO5 Inorganic materials 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 238000009841 combustion method Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 230000008821 health effect Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 238000002459 porosimetry Methods 0.000 description 1
- AABBHSMFGKYLKE-SNAWJCMRSA-N propan-2-yl (e)-but-2-enoate Chemical compound C\C=C\C(=O)OC(C)C AABBHSMFGKYLKE-SNAWJCMRSA-N 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 230000026683 transduction Effects 0.000 description 1
- 238000010361 transduction Methods 0.000 description 1
- 239000011882 ultra-fine particle Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/63—Platinum group metals with rare earths or actinides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/50—Catalysts, in general, characterised by their form or physical properties characterised by their shape or configuration
- B01J35/56—Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/02—Impregnation, coating or precipitation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/022—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
- F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/28—Construction of catalytic reactors
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Biomedical Technology (AREA)
- Toxicology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Exhaust Gas After Treatment (AREA)
- Processes For Solid Components From Exhaust (AREA)
Abstract
内燃機関から排出される排ガスを浄化する排ガス浄化触媒であって、排ガス導入側の端部が開口した導入側セルと、該導入側セルに隣接し排ガス排出側の端部が開口した排出側セルとが、多孔質の隔壁により画定されたウォールフロー型基材と、前記隔壁の気孔内に形成された触媒層と、を有し、気孔径分布において、前記ウォールフロー型基材の前記隔壁のモード気孔径をＸとしたときに、前記触媒層が形成された前記隔壁のモード気孔径が０．９Ｘ以下である、排ガス浄化触媒。【選択図】図１An exhaust gas purifying catalyst for purifying exhaust gas discharged from an internal combustion engine, an introduction side cell having an open end on the exhaust gas introduction side, and an exhaust side cell having an open end on the exhaust gas discharge side adjacent to the introduction side cell And a wall flow type substrate defined by porous partition walls, and a catalyst layer formed in the pores of the partition walls, and in the pore size distribution, the partition walls of the wall flow type substrate An exhaust gas purification catalyst, wherein the mode pore diameter of the partition wall on which the catalyst layer is formed is 0.9X or less when the mode pore diameter is X. [Selection] Figure 1
Description
本発明は、排ガス浄化触媒に関する。 The present invention relates to an exhaust gas purification catalyst.
内燃機関から排出される排ガスには、炭素を主成分とする粒子状物質（ＰＭ）、不燃成分からなるアッシュなどが含まれ、大気汚染の原因となることが知られている。従来、ガソリンエンジンよりも比較的に粒子状物質を排出しやすいディーゼルエンジンでは、粒子状物質の排出量が厳しく規制されていたが、近年、ガソリンエンジンにおいても粒子状物質の排出量の規制が強化されつつある。 It is known that exhaust gas discharged from an internal combustion engine contains particulate matter (PM) mainly composed of carbon, ash composed of incombustible components, and the like, and causes air pollution. Conventionally, diesel engines that discharge particulate matter relatively easily than gasoline engines have been strictly regulated in particulate matter emissions. However, in recent years, regulations on particulate matter emissions have also been tightened in gasoline engines. It is being done.
粒子状物質の排出量を低減するための手段としては、内燃機関の排ガス通路に粒子状物質を堆積させ捕集することを目的としたパティキュレートフィルタを設ける方法が知られている。特に、近年では、搭載スペースの省スペース化等の観点から、粒子状物質の排出抑制と、一酸化炭素（ＣＯ）、炭化水素（ＨＣ）及び窒素酸化物（ＮＯｘ）等の有害成分の除去を同時に行うために、パティキュレートフィルタに触媒スラリーを塗工し、これを焼成することで触媒層を設けることが検討されている。 As a means for reducing the discharge amount of particulate matter, there is known a method of providing a particulate filter for the purpose of depositing and collecting particulate matter in an exhaust gas passage of an internal combustion engine. In particular, in recent years, from the viewpoint of space saving, etc., the emission of particulate matter and the removal of harmful components such as carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) have been reduced. In order to carry out at the same time, it has been studied to apply a catalyst slurry to a particulate filter and to fire a catalyst slurry to provide a catalyst layer.
排ガス導入側の端部が開口した導入側セルと、該導入側セルに隣接し排ガス排出側の端部が開口した排出側セルとが、多孔質の隔壁により画定されたウォールフロー型基材を備えるパティキュレートフィルタに対して、このような触媒層の形成方法としては、スラリーの粘度や固形分率などの性状を調整し、導入側セル又は排出側セルの一方を加圧して、導入側セルと排出側セルに圧力差を生じさせることにより、触媒スラリーの隔壁内への浸透を調整する方法が知られている（例えば、特許文献１参照）。 A wall flow type substrate in which an introduction side cell having an open end on the exhaust gas introduction side and a discharge side cell having an open end on the exhaust gas discharge side adjacent to the introduction side cell is defined by a porous partition wall. As a method for forming such a catalyst layer for the particulate filter provided, the properties such as the viscosity and solid content of the slurry are adjusted, and one of the introduction side cell or the discharge side cell is pressurized to introduce the cell. And a method of adjusting the permeation of the catalyst slurry into the partition walls by generating a pressure difference between the discharge side cells (see, for example, Patent Document 1).
特許文献１に記載されるようなパティキュレートフィルタは、粒子状物質の除去の観点からウォールフロー型構造を有し、排ガスが隔壁の気孔内を通過するように構成される。しかしながら、スス捕集性能に関して、依然として改善の余地がある。 The particulate filter described in Patent Document 1 has a wall flow type structure from the viewpoint of removal of particulate matter, and is configured so that exhaust gas passes through the pores of the partition walls. However, there is still room for improvement in terms of soot collection performance.
また、従来、自動車のディーゼルエンジンから排出される粒子状物質は排出質量で規制されてきた。しかし、排出質量では人体に侵入しやすく健康への影響が懸念されている超微小粒子は数値に反映されにくい。そのため、近年では排出個数で粒子を規制するＰＮ（Ｐａｒｔｉｃｕｌａｔｅ Ｎｕｍｂｅｒ）規制が導入されている。 Conventionally, particulate matter discharged from automobile diesel engines has been regulated by emission mass. However, the ultra-fine particles that are easy to enter the human body and are concerned about their health effects are difficult to reflect in the numerical values. Therefore, in recent years, PN (Particulate Number) regulation that regulates particles by the number of discharged particles has been introduced.
これまでは、ガソリンエンジンでは粒子状物質の排出質量がディーゼルエンジンに比べて極めて少なかった。そのため、ガソリンエンジンに対する粒子状物質の排出質量規制はディーゼルエンジンに比べると積極的に行われてこなかった。しかし、近年ではガソリンエンジン向けにＰＮ規制が導入されつつある。 So far, gasoline engines have had very little particulate matter emissions compared to diesel engines. For this reason, particulate matter emission mass regulations for gasoline engines have not been actively implemented compared to diesel engines. In recent years, however, PN regulations have been introduced for gasoline engines.
ガソリンエンジンにおいて排出される粒子状物質の量と、ディーゼルエンジンにおいて排出される粒子状物質の量は異なるものである。例えば、ガソリンエンジンの場合のＰＭ粒子数規制（６×１０The amount of particulate matter discharged in a gasoline engine is different from the amount of particulate matter discharged in a diesel engine. For example, regulation of the number of PM particles for a gasoline engine (6 × 10
1111
／ｋｍ）は、ＰＭ質量に換算すると０．４〜０．５ｍｇ／ｋｍに相当するといわれる。これに対し、ディーゼルエンジンにおける粒子状物質の規制値は５ｍｇ／ｋｍ（０．００５ｇ／ｋｍ）とされている。このように、粒子状物質の規制と言えど、ガソリンエンジンとディーゼルエンジンとは、求められる捕集性能に違いがある。/ Km) is said to correspond to 0.4 to 0.5 mg / km in terms of PM mass. On the other hand, the regulation value of particulate matter in a diesel engine is set to 5 mg / km (0.005 g / km). Thus, although it is regulation of particulate matter, a gasoline engine and a diesel engine differ in required collection performance.
一般的に、捕集性能を向上させようとすれば、目の細かいフィルターを用いることとなり圧力損失の増大を招く。そのため、ディーゼルエンジンとは燃焼方式や排気温度などが全く異なるガソリンエンジンに対するＰＮ規制に対応しつつ、圧力損失を増加させずに、ガソリンエンジンから排出されるススの排出個数の低減を達成可能な技術が望まれる。 Generally, if it is intended to improve the collection performance, a fine filter is used, which causes an increase in pressure loss. Therefore, a technology that can achieve a reduction in the number of soot discharged from a gasoline engine without increasing the pressure loss, while complying with PN regulations for a gasoline engine that has completely different combustion methods and exhaust temperatures from a diesel engine. Is desired.
本発明は、上記課題に鑑みてなされたものであり、その目的は、ＰＮ規制に対応すべく、圧力損失を増大させずにススの捕集性能が高められた排ガス浄化触媒を提供することにある。なお、ここでいう目的に限らず、後述する発明を実施するための形態に示す各構成により導かれる作用効果であって、従来の技術によっては得られない作用効果を奏することも、本発明の他の目的として位置づけることができる。 The present invention has been made in view of the above problems, and an object of the present invention is to provide an exhaust gas purifying catalyst with improved soot collection performance without increasing pressure loss in order to comply with PN regulations. is there. Note that the present invention is not limited to the purpose described here, and is an operational effect derived from each configuration shown in the embodiment for carrying out the invention described later, and can also exhibit an operational effect that cannot be obtained by the conventional technology. It can be positioned as another purpose.
本発明者らは、ススの捕集性能の向上方法について鋭意検討を重ねた。その結果、ススが通過しやすい大径の気孔を減少させるとともに、スス捕集に適した小径の気孔を減少させないような触媒層を形成することによりススの捕集性能が向上することを見出し、本発明を完成するに至った。すなわち、本発明は、以下に示す種々の具体的態様を提供する。 The inventors of the present invention have made extensive studies on a method for improving the soot collection performance. As a result, it has been found that the soot collection performance is improved by forming a catalyst layer that reduces the large-diameter pores through which soot easily passes and does not reduce the small-diameter pores suitable for soot collection. The present invention has been completed. That is, the present invention provides various specific modes shown below.
〔１〕[1]
ガソリンエンジンから排出される排ガスを浄化する排ガス浄化触媒であって、 An exhaust gas purification catalyst for purifying exhaust gas discharged from a gasoline engine,
排ガス導入側の端部が開口した導入側セルと、該導入側セルに隣接し排ガス排出側の端部が開口した排出側セルとが、多孔質の隔壁により画定されたウォールフロー型基材と、 A wall flow type substrate in which an introduction side cell having an open end on the exhaust gas introduction side and an exhaust side cell having an open end on the exhaust gas discharge side adjacent to the introduction side cell are defined by a porous partition; ,
前記隔壁の気孔内に形成された触媒層と、を有し、 A catalyst layer formed in the pores of the partition wall,
気孔径分布において、前記ウォールフロー型基材の前記隔壁のモード気孔径をＸとしたときに、前記触媒層が形成された前記隔壁のモード気孔径が０．６Ｘ以上０．９Ｘ以下であり、 In the pore diameter distribution, when the mode pore diameter of the partition wall of the wall flow type substrate is X, the mode pore diameter of the partition wall on which the catalyst layer is formed is 0.6X or more and 0.9X or less,
最小気孔径を１μｍとする気孔径分布において、 In the pore size distribution with a minimum pore size of 1 μm,
前記ウォールフロー型基材の隔壁のＤ３０気孔径をＹとしたときに、前記触媒層が形成された前記隔壁のＤ３０気孔径が０．６９〜０．８０Ｙであり、 When the D30 pore diameter of the partition wall of the wall flow type substrate is Y, the D30 pore diameter of the partition wall on which the catalyst layer is formed is 0.69 to 0.80 Y,
前記ウォールフロー型基材の隔壁のＤ７０気孔径をＺとしたときに、前記触媒層が形成された前記隔壁のＤ７０気孔径が０．８０〜０．９０Ｚであり、 When the D70 pore diameter of the partition wall of the wall flow type substrate is Z, the D70 pore diameter of the partition wall on which the catalyst layer is formed is 0.80 to 0.90 Z,
前記モード気孔径の狭小率ＮＲ Narrowing ratio NR of the mode pore diameter
MM
に対する前記Ｄ３０気孔径の狭小率ＮＲD30 pore size narrowing ratio NR
D30D30
の比率（ＮＲRatio (NR
D30D30
／ＮＲ/ NR
MM
）が、０．８７〜０．９５である、) Is 0.87-0.95,
排ガス浄化触媒。 Exhaust gas purification catalyst.
〔２〕[2]
前記ウォールフロー型基材の前記隔壁の前記モード気孔径Ｘが、１０〜３０μｍである、 The mode pore diameter X of the partition wall of the wall flow type substrate is 10 to 30 μm.
〔１〕に記載の排ガス浄化触媒。 The exhaust gas purification catalyst according to [1].
〔３〕[3]
前記触媒層が形成された前記隔壁のモード気孔径が０．６５Ｘ以上０．８９Ｘ以下である、 The mode pore diameter of the partition wall on which the catalyst layer is formed is 0.65X or more and 0.89X or less.
〔１〕又は〔２〕に記載の排ガス浄化触媒。 The exhaust gas purification catalyst according to [1] or [2].
〔４〕[4]
前記ウォールフロー型基材の前記隔壁の気孔率が、６０〜７０％である、 The porosity of the partition walls of the wall flow type substrate is 60 to 70%.
〔１〕〜〔３〕のいずれか一項に記載の排ガス浄化触媒。 The exhaust gas purifying catalyst according to any one of [1] to [3].
〔５〕[5]
ガソリンエンジンから排出される排ガスを浄化する排ガス浄化触媒の製造方法であって、 An exhaust gas purification catalyst manufacturing method for purifying exhaust gas discharged from a gasoline engine,
排ガス導入側の端部が開口した導入側セルと、該導入側セルに隣接し排ガス排出側の端部が開口した排出側セルとが、多孔質の隔壁により画定されたウォールフロー型基材を準備する工程と、 A wall flow type substrate in which an introduction side cell having an open end on the exhaust gas introduction side and a discharge side cell having an open end on the exhaust gas discharge side adjacent to the introduction side cell is defined by a porous partition wall. A preparation process;
前記ウォールフロー型基材の前記隔壁内の気孔表面上の少なくとも一部に、触媒スラリーを塗工して、触媒層を形成する触媒層形成工程と、を有し、 A catalyst layer forming step of applying a catalyst slurry to at least a part of the pore surface in the partition wall of the wall flow type substrate to form a catalyst layer, and
該触媒層形成工程において、気孔径分布において、前記ウォールフロー型基材の隔壁のモード気孔径をＸとしたときに、前記触媒層が形成された前記隔壁のモード気孔径が０．６Ｘ以上０．９Ｘ以下であり、最小気孔径を１μｍとする気孔径分布において、前記ウォールフロー型基材の隔壁のＤ３０気孔径をＹとしたときに、前記触媒層が形成された前記隔壁のＤ３０気孔径が０．６９〜０．８０Ｙであり、前記ウォールフロー型基材の隔壁のＤ７０気孔径をＺとしたときに、前記触媒層が形成された前記隔壁のＤ７０気孔径が０．８０〜０．９０Ｚであり、前記モード気孔径の狭小率ＮＲ In the catalyst layer forming step, in the pore size distribution, when the mode pore diameter of the partition wall of the wall flow type substrate is X, the mode pore diameter of the partition wall on which the catalyst layer is formed is 0.6X or more and 0 .9X or less, and in the pore size distribution where the minimum pore size is 1 μm, when the D30 pore size of the partition wall of the wall flow type substrate is Y, the D30 pore size of the partition wall on which the catalyst layer is formed Is 0.69 to 0.80 Y, and when the D70 pore diameter of the partition wall of the wall flow type substrate is Z, the D70 pore diameter of the partition wall on which the catalyst layer is formed is 0.80 to 0.8. 90Z, the mode pore diameter narrowing ratio NR
MM
に対する前記Ｄ３０気孔径の狭小率ＮＲD30 pore size narrowing ratio NR
D30D30
の比率（ＮＲRatio (NR
D30D30
／ＮＲ/ NR
MM
）が、０．８７〜０．９５である前記排ガス浄化触媒を得る、) To obtain the exhaust gas purification catalyst of 0.87 to 0.95,
排ガス浄化触媒の製造方法。 A method for producing an exhaust gas purification catalyst.
本発明によれば、ススの捕集性能が高められた排ガス浄化触媒等を提供することができる。そして、この排ガス浄化触媒は、触媒を担持したガソリンパティキュレートフィルタ（ＧＰＦ）として有効に利用することができ、このようなパティキュレートフィルタを搭載した排ガス処理システムの一層の高性能化が図られる。 ADVANTAGE OF THE INVENTION According to this invention, the exhaust gas purification catalyst etc. with which the collection performance of soot was improved can be provided. And this exhaust gas purification catalyst can be effectively used as a gasoline particulate filter (GPF) carrying a catalyst, and further enhancement of performance of an exhaust gas treatment system equipped with such a particulate filter can be achieved.
以下、本発明の実施の形態について詳細に説明する。以下の実施の形態は、本発明の実施態様の一例（代表例）であり、本発明はこれらに限定されるものではない。また、本発明は、その要旨を逸脱しない範囲内で任意に変更して実施することができる。なお、本明細書において、上下左右等の位置関係は、特に断らない限り、図面に示す位置関係に基づくものとする。また、図面の寸法比率は、図示の比率に限定されるものではない。本明細書において、「モード気孔径」とは、気孔径の頻度分布における出現比率がもっとも大きい気孔径（分布の極大値）をいい、「Ｄ３０気孔径」とは、最小気孔径を１μｍとする体積基準の気孔径の累積分布において小孔径からの積算値が全体の３０％に達したときの気孔径をいい、「Ｄ７０気孔径」とは、最小気孔径を１μｍとする体積基準の気孔径の累積分布において小孔径からの積算値が全体の７０％に達したときの気孔径をいう。また、「Ｄ９０粒子径」とは、体積基準の粒子径の累積分布において小粒径からの積算値が全体の９０％に達したときの粒子径をいう。また、本明細書において、「〜」を用いてその前後に数値又は物性値を挟んで表現する場合、その前後の値を含むものとして用いる。例えば「１〜１００」との数値範囲の表記は、その下限値「１」及び上限値「１００」の双方を包含するものとする。また、他の数値範囲の表記も同様である。 Hereinafter, embodiments of the present invention will be described in detail. The following embodiments are examples (representative examples) of the embodiments of the present invention, and the present invention is not limited to these. In addition, the present invention can be implemented with any modifications without departing from the scope of the invention. In the present specification, the positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios. In this specification, “mode pore diameter” means a pore diameter (maximum value of distribution) having the highest appearance ratio in the frequency distribution of pore diameters, and “D30 pore diameter” means a minimum pore diameter of 1 μm. In the cumulative distribution of the volume-based pore diameter, the pore diameter when the integrated value from the small pore diameter reaches 30% of the total, and “D70 pore diameter” is the volume-based pore diameter with a minimum pore diameter of 1 μm. In the cumulative distribution, the pore diameter when the integrated value from the small pore diameter reaches 70% of the total. The “D90 particle size” refers to the particle size when the integrated value from the small particle size reaches 90% of the total in the cumulative distribution of the particle size on the volume basis. In addition, in this specification, when a numerical value or a physical property value is put before and after using “to”, the value before and after that is used. For example, the description of a numerical range of “1 to 100” includes both the lower limit value “1” and the upper limit value “100”. This also applies to other numerical range notations.
［排ガス浄化触媒］
本実施形態の排ガス浄化触媒は、内燃機関であるガソリンエンジンから排出される排ガスを浄化する排ガス浄化触媒１００であって、排ガス導入側の端部１１ａが開口した導入側セル１１と、該導入側セル１１に隣接し排ガス排出側の端部１２ａが開口した排出側セル１２とが、多孔質の隔壁１３により画定されたウォールフロー型基材１０と、隔壁１３の気孔内に形成された触媒層２１と、を有し、気孔径分布において、ウォールフロー型基材１０の隔壁１３のモード気孔径をＸとしたときに、触媒層２１が形成された隔壁１３のモード気孔径が０．６Ｘ以上０．９Ｘ以下であり、最小気孔径を１μｍとする気孔径分布において、前記ウォールフロー型基材の隔壁のＤ３０気孔径をＹとしたときに、前記触媒層が形成された前記隔壁のＤ３０気孔径が０．５５〜０．８０Ｙであり、前記ウォールフロー型基材の隔壁のＤ７０気孔径をＺとしたときに、前記触媒層が形成された前記隔壁のＤ７０気孔径が０．７０〜０．９０Ｚであることを特徴とする。
[Exhaust gas purification catalyst]
The exhaust gas purifying catalyst of the present embodiment is an exhaust gas purifying catalyst 100 that purifies exhaust gas discharged from a gasoline engine that is an internal combustion engine, an introduction side cell 11 having an open end 11a on the exhaust gas introduction side, and the introduction side A discharge-side cell 12 adjacent to the cell 11 and having an open end 12a on the exhaust gas discharge side is defined by a porous partition wall 13 and a catalyst layer formed in the pores of the partition wall 13 In the pore size distribution, when the mode pore size of the partition wall 13 of the wall flow type substrate 10 is X, the mode pore size of the partition wall 13 on which the catalyst layer 21 is formed is 0.6X or more. In a pore size distribution of 0.9X or less and a minimum pore size of 1 μm, when the D30 pore size of the partition wall of the wall flow type substrate is Y, D3 of the partition wall in which the catalyst layer is formed The pore diameter is 0.55 to 0.80Y, and when the D70 pore diameter of the partition wall of the wall flow type substrate is Z, the D70 pore diameter of the partition wall on which the catalyst layer is formed is 0.70. It is 0.90Z.
以下、図１に示す、本実施形態の排ガス浄化触媒を模式的に示す断面図を参照しつつ、各構成について説明する。本実施形態の排ガス浄化触媒はウォールフロー型構造を有する。このような構造を有する排ガス浄化触媒１００では、内燃機関から排出される排ガスが、排ガス導入側の端部１１ａ（開口）から導入側セル１１内へと流入し、隔壁１３の気孔内を通過して隣接する排出側セル１２内へ流入し、排ガス排出側の端部１２ａ（開口）から流出する。この過程において、隔壁１３の気孔内を通り難い粒子状物質（ＰＭ）は、一般に、導入側セル１１内の隔壁１３上及び／又は隔壁１３の気孔内に堆積し、堆積した粒子状物質は、触媒層２１の触媒機能によって、或いは所定の温度（例えば５００〜７００℃程度）で燃焼し、除去される。また、排ガスは、隔壁１３の気孔内に形成された触媒層２１と接触し、これによって排ガスに含まれる一酸化炭素（ＣＯ）や炭化水素（ＨＣ）は水（Ｈ2Ｏ）や二酸化炭素（ＣＯ2）などへ酸化され、窒素酸化物（ＮＯｘ）は窒素（Ｎ2）へ還元され、有害成分が浄化（無害化）される。なお、本明細書においては、粒子状物質の除去及び一酸化炭素（ＣＯ）等の有害成分の浄化をまとめて「排ガス浄化性能」ともいう。以下、各構成についてより詳細に説明する。 Hereafter, each structure is demonstrated, referring sectional drawing which shows typically the exhaust gas purification catalyst of this embodiment shown in FIG. The exhaust gas purification catalyst of the present embodiment has a wall flow type structure. In the exhaust gas purification catalyst 100 having such a structure, the exhaust gas discharged from the internal combustion engine flows into the introduction side cell 11 from the end portion 11a (opening) on the exhaust gas introduction side, and passes through the pores of the partition wall 13. Into the adjacent discharge side cell 12 and out of the end 12a (opening) on the exhaust gas discharge side. In this process, the particulate matter (PM) that hardly passes through the pores of the partition wall 13 is generally deposited on the partition wall 13 in the introduction side cell 11 and / or in the pores of the partition wall 13. It is burned and removed by the catalytic function of the catalyst layer 21 or at a predetermined temperature (for example, about 500 to 700 ° C.). Further, the exhaust gas comes into contact with the catalyst layer 21 formed in the pores of the partition wall 13, whereby carbon monoxide (CO) and hydrocarbon (HC) contained in the exhaust gas are water (H 2 O) and carbon dioxide ( Oxidized to CO 2 ) and the like, nitrogen oxides (NOx) are reduced to nitrogen (N 2 ), and harmful components are purified (detoxified). In the present specification, removal of particulate matter and purification of harmful components such as carbon monoxide (CO) are collectively referred to as “exhaust gas purification performance”. Hereinafter, each configuration will be described in more detail.
（気孔径）
ガソリンエンジンはディーゼルエンジンよりもより高温で稼働するため、排ガスに含まれる粒子状物質の径はディーゼルエンジンよりもより小さくなる傾向にある。粒子状物質は、その径によって捕集モードが異なる。ガソリンエンジンから排出される粒子状物質の粒子径は一般に百ｎｍ程度である。このような小径の粒子状物質の捕集モードとしては、粒子の拡散寄与が大きい。つまり、フィルターにおいては粒子状物質が通過する細孔の径を狭小化し、粒子との接触頻度を向上するように設計することで粒子状物質の捕集性能の向上に繋がると考えられる。
(Pore size)
Since the gasoline engine operates at a higher temperature than the diesel engine, the diameter of the particulate matter contained in the exhaust gas tends to be smaller than that of the diesel engine. The particulate matter has a different collection mode depending on its diameter. The particle size of the particulate matter discharged from the gasoline engine is generally about 100 nm. As such a small-diameter particulate matter collection mode, the particle diffusion contribution is large. That is, it is considered that the filter is designed to reduce the diameter of the pores through which the particulate matter passes and to improve the frequency of contact with the particles, thereby improving the collection performance of the particulate matter.
これを踏まえ、本実施形態の排ガス浄化触媒は、触媒層２１の形成により気孔径を小径化することでススが通過しやすい大径の気孔を減少させるとともに、触媒層２１の形成による気孔の閉塞を抑制することでスス捕集に適した小径の気孔を維持することにより、スス捕集性能を向上させる。このような観点から、本実施形態においては、触媒層２１を形成する前の隔壁１３の気孔径分布と、触媒層２１が形成された隔壁１３の気孔径分布が所定の関係を有することを規定する。具体的には、触媒層２１を形成する前の隔壁１３のモード気孔径Ｘに対して、触媒層２１が形成された隔壁１３のモード気孔径の関係を規定することにより、それぞれの気孔径分布の関係を規定する。また、それぞれの気孔径分布の関係をより詳細に規定する好ましい態様においては、触媒層２１を形成する前の隔壁１３と触媒層２１が形成された隔壁１３におけるＤ３０気孔径及びＤ７０気孔径が有する関係についてもそれぞれ規定する。 Based on this, the exhaust gas purifying catalyst of the present embodiment reduces the pore diameter through which the soot easily passes by reducing the pore diameter by forming the catalyst layer 21, and closes the pores by forming the catalyst layer 21. By maintaining a small-diameter pore suitable for soot collection by suppressing the soot collection performance, soot collection performance is improved. From this point of view, in the present embodiment, the pore size distribution of the partition wall 13 before the catalyst layer 21 is formed and the pore size distribution of the partition wall 13 on which the catalyst layer 21 is formed have a predetermined relationship. To do. Specifically, by defining the relationship of the mode pore diameter of the partition wall 13 in which the catalyst layer 21 is formed with respect to the mode pore diameter X of the partition wall 13 before the catalyst layer 21 is formed, the respective pore diameter distributions. Specify the relationship. Moreover, in the preferable aspect which prescribes | regulates the relationship of each pore diameter distribution in detail, it has D30 pore diameter and D70 pore diameter in the partition 13 before forming the catalyst layer 21 and the partition 13 in which the catalyst layer 21 was formed. Each relationship is also specified.
気孔径分布において、ウォールフロー型基材１０の隔壁１３のモード気孔径をＸとしたときに、触媒層２１が形成された隔壁１３のモード気孔径は、０．９Ｘ以下であり、好ましくは０．６Ｘ以上０．８９Ｘ以下であり、より好ましくは０．６５Ｘ以上０．８８Ｘ以下であり、０．６５Ｘ以上０．８５Ｘ以下である。触媒層２１が形成された隔壁１３のモード気孔径が０．９Ｘ以下であることにより、ススの捕集性能がより向上する。また、触媒層２１が形成された隔壁１３のモード気孔径が０．６Ｘ以上であることにより、圧力損失の上昇がより抑制される傾向にある。なお、「０．９Ｘ」という表記における「０．９」という乗数は、ウォールフロー型基材の隔壁のモード気孔径に対する、触媒層が形成された隔壁のモード気孔径の割合を示し、当該乗数を１００％表記で示したものを気孔狭小率ともいう。以下、モード気孔径の気孔狭小率をＮＲMといい、後述するＤ３０気孔径の気孔狭小率をＮＲD30といい、Ｄ７０気孔径の気孔狭小率をＮＲD70という。 In the pore diameter distribution, when the mode pore diameter of the partition wall 13 of the wall flow type substrate 10 is X, the mode pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.9X or less, preferably 0. .6X or more and 0.89X or less, more preferably 0.65X or more and 0.88X or less, and 0.65X or more and 0.85X or less. When the mode pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.9X or less, the soot collection performance is further improved. Moreover, when the mode pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.6X or more, an increase in pressure loss tends to be further suppressed. The multiplier of “0.9” in the notation of “0.9X” indicates the ratio of the mode pore diameter of the partition wall on which the catalyst layer is formed to the mode pore diameter of the partition wall of the wall flow type substrate, and the multiplier Is expressed as a pore narrowing rate. Hereinafter, the pores narrowing ratio mode pore diameter called NR M, pore narrowing ratio of D30 pore diameter, which will be described later called NR D30, the pores narrowing ratio of D70 pore diameter of NR D70.
また、触媒層２１の形成による気孔の閉塞を抑制し、スス捕集に適した小径の気孔が維持されることをより直接的に規定する観点から、最小気孔径を１μｍとする気孔径分布において、ウォールフロー型基材１０の隔壁１３のＤ３０気孔径をＹとしたときの、触媒層２１が形成された隔壁１３のＤ３０気孔径を規定することが好ましい。触媒層２１が形成された隔壁１３のＤ３０気孔径は、０．５５Ｙ以上０．８０Ｙ以下であり、好ましくは０．６０Ｙ以上０．８０Ｙ以下であり、より好ましくは０．６５Ｙ以上０．８０Ｙ以下であり、さらに好ましくは０．６５Ｙ以上０．７５Ｙ以下である。触媒層２１が形成された隔壁１３のＤ３０気孔径が０．８０Ｙ以下であることにより、ススの捕集性能がより向上する傾向にある。また、触媒層２１が形成された隔壁１３のＤ３０気孔径が０．５５Ｙ以上であることにより、圧力損失の上昇がより抑制される傾向にある。 Further, in the pore size distribution in which the minimum pore size is 1 μm from the viewpoint of more directly regulating that the pores with small diameter suitable for soot collection are maintained by suppressing the clogging of the pores due to the formation of the catalyst layer 21. It is preferable to define the D30 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed, where Y is the D30 pore diameter of the partition wall 13 of the wall flow type substrate 10. The D30 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.55Y or more and 0.80Y or less, preferably 0.60Y or more and 0.80Y or less, more preferably 0.65Y or more and 0.80Y or less. More preferably, it is 0.65Y or more and 0.75Y or less. When the D30 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.80Y or less, the soot collection performance tends to be further improved. Moreover, when the D30 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.55Y or more, an increase in pressure loss tends to be further suppressed.
さらに、触媒層２１の形成により気孔径を小径化し、ススが通過しやすい大径の気孔が減少することをより直接的に規定する観点から、最小気孔径を１μｍとする気孔径分布において、ウォールフロー型基材の隔壁のＤ７０気孔径をＺとしたときの、触媒層２１が形成された隔壁１３のＤ７０気孔径を規定することが好ましい。触媒層２１が形成された隔壁１３のＤ７０気孔径は、０．７０Ｚ以上０．９０Ｚ以下であり、好ましくは０．７５Ｚ以上０．９０Ｚ以下であり、より好ましくは０．８０Ｚ以上０．９０Ｚ以下である。触媒層２１が形成された隔壁１３のＤ７０気孔径が０．９０Ｚ以下であることにより、ススの捕集性能がより向上する傾向にある。また、触媒層２１が形成された隔壁１３のＤ７０気孔径が０．７０Ｚ以上であることにより、圧力損失の上昇がより抑制される傾向にある。 Furthermore, from the viewpoint of directly defining that the pore size is reduced by forming the catalyst layer 21 and the large pores through which soot easily passes are reduced, It is preferable to define the D70 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed when the D70 pore diameter of the partition wall of the flow type substrate is Z. The D70 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.70 Z or more and 0.90 Z or less, preferably 0.75 Z or more and 0.90 Z or less, more preferably 0.80 Z or more and 0.90 Z or less. It is. When the D70 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.90 Z or less, the soot collection performance tends to be further improved. Moreover, when the D70 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.70 Z or more, an increase in pressure loss tends to be further suppressed.
また、触媒層２１の形成により気孔径を小径化することでススが通過しやすい大径の気孔を減少させるとともに、触媒層２１の形成による気孔の閉塞を抑制することでスス捕集に適した小径の気孔を維持するという観点から、モード気孔径の気孔狭小率ＮＲM、Ｄ３０気孔径の気孔狭小率ＮＲD30、Ｄ７０気孔径の気孔狭小率ＮＲD70は以下の関係を有することが好ましい。 Further, by reducing the pore diameter by forming the catalyst layer 21, the large-diameter pores through which soot easily passes are reduced, and by suppressing the clogging of the pores due to the formation of the catalyst layer 21, it is suitable for collecting soot. from the viewpoint of maintaining the small diameter pores, pore narrowing rate NR M mode pore diameter, D30 pore narrowing ratio of pore diameter NR D30 pore narrowing ratio NR D70 of D70 pore diameter preferably has the following relationship.
気孔狭小率ＮＲMに対する気孔狭小率ＮＲD30の比率（ＮＲD30／ＮＲM）は、好ましくは１未満であり、より好ましくは０．５〜０．９５であり、さらに好ましくは０．６〜０．９である。また、気孔狭小率ＮＲMに対する気孔狭小率ＮＲD70の比率（ＮＲD70／ＮＲM）は、好ましくは０．９〜１．３であり、より好ましくは１．０１〜１．２であり、さらに好ましくは１．０２〜１．１である。このように、ススが通過しやすい大径の気孔を減少させつつ、スス捕集に適した小径の気孔を維持することにより、圧力損失の上昇を抑制しつつススの捕集率が向上する傾向にある。 The ratio of the pore narrowing ratio NR D30 for pore narrowing rate NR M (NR D30 / NR M ) is preferably less than 1, more preferably from 0.5 to 0.95, more preferably 0.6 to 0 .9. The ratio of the pore narrowing ratio NR D70 for pore narrowing rate NR M (NR D70 / NR M ) is preferably 0.9 to 1.3, more preferably from 1.01 to 1.2, further Preferably it is 1.02-1.1. In this way, by reducing the large-diameter pores through which soot easily passes, maintaining the small-diameter pores suitable for soot collection tends to improve the soot collection rate while suppressing an increase in pressure loss. It is in.
また、排ガス浄化触媒の全気孔容積は、０．４ｃｃ／ｇ以上であり、より好ましくは０．４〜０．８ｃｃ／ｇであり、さらに好ましくは０．５〜０．７ｃｃ／ｇである。全気孔容積が０．４ｃｃ／ｇ以上であることにより、圧力損失の向上がより抑制される傾向にある。 Further, the total pore volume of the exhaust gas purification catalyst is 0.4 cc / g or more, more preferably 0.4 to 0.8 cc / g, and further preferably 0.5 to 0.7 cc / g. When the total pore volume is 0.4 cc / g or more, improvement in pressure loss tends to be further suppressed.
なお、各気孔径及び全気孔容積は、下記実施例に記載の条件において水銀圧入法により算出される値を意味する。 In addition, each pore diameter and total pore volume mean values calculated by the mercury intrusion method under the conditions described in the following examples.
触媒層２１が形成された隔壁１３のモード気孔径を調整する方法としては、特に制限されないが、例えば、隔壁１３の気孔内に形成する触媒層の塗工量を調整するとともに、所定の触媒層の塗工量条件下において、触媒層２１により閉塞する小径の気孔を減少させる方法が挙げられる。小径の気孔の閉塞を抑制する方法としては、触媒スラリーのｐＨの調整により、触媒スラリーの粘度を調整することにより、毛細管現象による小径の気孔への触媒スラリーの集中を緩和する方法が挙げられる。なお、触媒層２１を形成する前の隔壁１３のモード気孔径Ｘ、Ｄ３０気孔径Ｙ、Ｄ７０気孔径Ｚは、ウォールフロー型基材の選択によって調整することができる。 The method for adjusting the mode pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is not particularly limited. For example, the coating amount of the catalyst layer formed in the pores of the partition wall 13 is adjusted, and a predetermined catalyst layer is formed. The method of reducing the small diameter pore obstruct | occluded by the catalyst layer 21 under the coating amount conditions of this is mentioned. As a method for suppressing the blockage of the small-diameter pores, there is a method of reducing the concentration of the catalyst slurry in the small-diameter pores due to capillary action by adjusting the viscosity of the catalyst slurry by adjusting the pH of the catalyst slurry. In addition, the mode pore diameter X, D30 pore diameter Y, and D70 pore diameter Z of the partition wall 13 before forming the catalyst layer 21 can be adjusted by selecting a wall flow type substrate.
なお、触媒層が形成された隔壁のＤ７０気孔径、及び、触媒層２１が形成された隔壁１３のＤ３０気孔径を所定の範囲に調整する方法も上記と同様とすることができる。また、全気孔容積を所定の範囲に調整する方法としては、触媒層の塗工量を調整する方法が挙げられる。 In addition, the method of adjusting the D70 pore diameter of the partition wall on which the catalyst layer is formed and the D30 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed can be the same as described above. Moreover, as a method of adjusting the total pore volume to a predetermined range, a method of adjusting the coating amount of the catalyst layer can be mentioned.
（基材）
ウォールフロー型基材１０は、排ガス導入側の端部１１ａが開口した導入側セル１１と、該導入側セル１１に隣接し排ガス排出側の端部１２ａが開口した排出側セル１２とが、多孔質の隔壁１３によって仕切られているウォールフロー型構造を有する。
(Base material)
The wall-flow-type substrate 10 is porous with an introduction side cell 11 having an open end 11a on the exhaust gas introduction side and an exhaust side cell 12 adjacent to the introduction side cell 11 and having an end 12a on the exhaust gas discharge side open. It has a wall flow type structure partitioned by quality partition walls 13.
基材１０としては、従来のこの種の用途に用いられる種々の材質及び形体のものが使用可能である。例えば、基材の材質は、内燃機関が高負荷条件で運転された際に生じる高温（例えば４００℃以上）の排ガスに曝された場合や、粒子状物質を高温で燃焼除去する場合などにも対応可能なように、耐熱性素材からなるものが好ましい。耐熱性素材としては、例えば、コージェライト、ムライト、チタン酸アルミニウム、及び炭化ケイ素（ＳｉＣ）等のセラミック；ステンレス鋼などの合金が挙げられる。また、基材の形体は、排ガス浄化性能及び圧力損失上昇抑制等の観点から適宜調整することが可能である。例えば、基材の外形は、円筒形状、楕円筒形状、又は多角筒形状等とすることができる。また、組み込む先のスペースなどにもよるが、基材の容量（セルの総体積）は、好ましくは０．１〜５Ｌであり、より好ましくは０．５〜３Ｌである。また、基材の延伸方向の全長（隔壁１３の延伸方向の全長）は、好ましくは１０〜５００ｍｍ、より好ましくは５０〜３００ｍｍである。 As the base material 10, various materials and shapes used for this kind of conventional applications can be used. For example, the material of the base material is also used when the internal combustion engine is exposed to high-temperature exhaust gas (for example, 400 ° C. or higher) generated when the internal combustion engine is operated under a high load condition, or when particulate matter is burned and removed at a high temperature. A material made of a heat-resistant material is preferable so as to be compatible. Examples of the heat resistant material include ceramics such as cordierite, mullite, aluminum titanate, and silicon carbide (SiC); alloys such as stainless steel. Further, the shape of the base material can be appropriately adjusted from the viewpoints of exhaust gas purification performance and suppression of pressure loss increase. For example, the outer shape of the substrate can be a cylindrical shape, an elliptical cylindrical shape, a polygonal cylindrical shape, or the like. Further, although it depends on the space to be incorporated, the capacity of the substrate (total volume of the cell) is preferably 0.1 to 5 L, more preferably 0.5 to 3 L. Moreover, the full length of the base material in the extending direction (the total length of the partition walls 13 in the extending direction) is preferably 10 to 500 mm, more preferably 50 to 300 mm.
導入側セル１１と排出側セル１２は、筒形状の軸方向に沿って規則的に配列されており、隣り合うセル同士は延伸方向の一の開口端と他の一の開口端とが交互に封止されている。導入側セル１１及び排出側セル１２は、供給される排ガスの流量や成分を考慮して適当な形状および大きさに設定することができる。例えば、導入側セル１１及び排出側セル１２の口形状は、三角形；正方形、平行四辺形、長方形、及び台形等の矩形；六角形及び八角形等のその他の多角形；円形とすることができる。また、導入側セル１１の断面積と、排出側セル１２の断面積とを異ならせたＨｉｇｈ Ａｓｈ Ｃａｐａｃｉｔｙ（ＨＡＣ）構造を有するものであってもよい。 The introduction side cell 11 and the discharge side cell 12 are regularly arranged along the axial direction of the cylindrical shape, and adjacent cells alternately have one open end and the other open end in the extending direction. It is sealed. The introduction side cell 11 and the discharge side cell 12 can be set to appropriate shapes and sizes in consideration of the flow rate and components of the supplied exhaust gas. For example, the mouth shape of the introduction side cell 11 and the discharge side cell 12 can be a triangle; a rectangle such as a square, a parallelogram, a rectangle, and a trapezoid; another polygon such as a hexagon and an octagon; a circle. . Moreover, you may have a High Ash Capacity (HAC) structure where the cross-sectional area of the introduction | transduction side cell 11 and the cross-sectional area of the discharge | emission side cell 12 differed.
なお、導入側セル１１及び排出側セル１２の個数は、排ガスの乱流の発生を促進し、かつ、排ガスに含まれる微粒子等による目詰まりを抑制できるように適宜設定することができ、特に限定されないが、好ましくは２００ｃｐｓｉ〜４００ｃｐｓｉである。また、隔壁１３の厚み（延伸方向に直交する厚さ方向の長さ）は、好ましくは６〜１２ｍｉｌであり、より好ましくは６〜１０ｍｉｌである。 The number of the introduction side cells 11 and the discharge side cells 12 can be set as appropriate so as to promote the generation of turbulence of the exhaust gas and to suppress clogging due to fine particles contained in the exhaust gas. Although not, it is preferably 200 cpsi to 400 cpsi. The thickness of the partition wall 13 (the length in the thickness direction orthogonal to the stretching direction) is preferably 6 to 12 mil, more preferably 6 to 10 mil.
隣り合うセル同士を仕切る隔壁１３は、排ガスが通過可能な多孔質構造を有するものであれば特に制限されず、その構成については、排ガス浄化性能や圧力損失の上昇抑制、基材の機械的強度の向上等の観点から適宜調整することができる。例えば、後述する触媒スラリーを用いて該隔壁１３内の気孔表面に触媒層２１を形成する場合、モード気孔径Ｘや気孔容積が大きい場合には、触媒層２１による気孔の閉塞が生じにくく、得られる排ガス浄化触媒は圧力損失が上昇しにくいものとなる傾向にあるが、粒子状物質の捕集能力が低下し、また、基材の機械的強度も低下する傾向にある。一方で、気孔径や気孔容積が小さい場合には、圧力損失が上昇しやすいものとなるが、粒子状物質の捕集能力は向上し、基材の機械的強度も向上する傾向にある。 The partition wall 13 for partitioning adjacent cells is not particularly limited as long as it has a porous structure through which exhaust gas can pass, and the configuration thereof includes exhaust gas purification performance, suppression of increase in pressure loss, and mechanical strength of the substrate. It can adjust suitably from viewpoints, such as an improvement. For example, when the catalyst layer 21 is formed on the surface of the pores in the partition wall 13 using a catalyst slurry described later, when the mode pore diameter X or the pore volume is large, the pores are not easily blocked by the catalyst layer 21. Although the exhaust gas purifying catalyst to be produced tends to have a pressure loss that is difficult to increase, the ability to collect particulate matter is lowered, and the mechanical strength of the substrate also tends to be lowered. On the other hand, when the pore diameter and pore volume are small, the pressure loss tends to increase, but the ability to collect particulate matter tends to improve and the mechanical strength of the substrate tends to improve.
このような観点から、隔壁１３の気孔率は、好ましくは２０〜８０％であり、より好ましくは４０〜７０％であり、さらに好ましくは６０〜７０％である。気孔率が下限以上であることにより、圧力損失の上昇がより抑制される傾向にある。また、気孔率が上限以下であることにより、基材の強度がより向上する傾向にある。なお、気孔率は、下記実施例に記載の条件において水銀圧入法により算出される値を意味する。 From such a viewpoint, the porosity of the partition wall 13 is preferably 20 to 80%, more preferably 40 to 70%, and further preferably 60 to 70%. When the porosity is equal to or higher than the lower limit, an increase in pressure loss tends to be further suppressed. Moreover, it exists in the tendency for the intensity | strength of a base material to improve more because a porosity is below an upper limit. The porosity means a value calculated by a mercury intrusion method under the conditions described in the following examples.
また、ウォールフロー型基材の隔壁のモード気孔径Ｘは、触媒層２１を形成する前の隔壁１３と触媒層２１が形成された隔壁１３におけるモード気孔径が上記各関係を有する場合において、ススの捕集性能と圧力損失の上昇抑制をよりバランスよく発揮する観点から、規定することができる。具体的には、気孔径分布において、ウォールフロー型基材の隔壁のモード気孔径Ｘは、好ましくは１０〜３０μｍであり、より好ましくは１２〜２８μｍであり、さらに好ましくは１５〜２５μｍである。 Further, the mode pore diameter X of the partition wall of the wall flow type base material is the soot when the mode pore diameter in the partition wall 13 before forming the catalyst layer 21 and the partition wall 13 where the catalyst layer 21 is formed has the above relationships. From the viewpoint of exhibiting a better balance between the collection performance and the increase in pressure loss, it can be specified. Specifically, in the pore size distribution, the mode pore size X of the partition wall of the wall flow type substrate is preferably 10 to 30 μm, more preferably 12 to 28 μm, and still more preferably 15 to 25 μm.
（触媒層）
次に、隔壁１３の気孔内に形成された触媒層２１について説明する。触媒層２１は、従来のこの種の用途に用いられる種々の態様のものが使用可能である。例えば、触媒層２１の態様として、触媒金属粒子と担体粒子とを含む触媒スラリーを焼成してなるものが挙げ有られる。このように各種粒子を含む触媒スラリーを焼成して形成される触媒層２１は、焼成により粒子同士が溶着した微多孔構造を有する。
(Catalyst layer)
Next, the catalyst layer 21 formed in the pores of the partition wall 13 will be described. The catalyst layer 21 can be used in various forms used for this type of conventional application. For example, as an aspect of the catalyst layer 21, there may be mentioned one obtained by firing a catalyst slurry containing catalyst metal particles and carrier particles. Thus, the catalyst layer 21 formed by firing the catalyst slurry containing various particles has a microporous structure in which the particles are welded together by firing.
触媒層２１に含まれる触媒金属としては、特に制限されず、種々の酸化触媒や還元触媒として機能し得る金属種を用いることができる。例えば、白金（Ｐｔ）、パラジウム（Ｐｄ）、ロジウム（Ｒｈ）、ルテニウム（Ｒｕ）、イリジウム（Ｉｒ）及びオスミウム（Ｏｓ）等の白金族金属が挙げられる。このなかでも、酸化活性の観点からはパラジウム（Ｐｄ）、白金（Ｐｔ）が好ましく、還元活性の観点からはロジウム（Ｒｈ）が好ましい。本実施形態においては、上記のとおり一種以上の触媒金属を混合された状態で含有する触媒層２１を有する。特に二種以上の触媒金属の併用により、異なる触媒活性を有することによる相乗的な効果が期待される。 The catalyst metal contained in the catalyst layer 21 is not particularly limited, and metal species that can function as various oxidation catalysts and reduction catalysts can be used. For example, platinum group metals such as platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), and osmium (Os) can be used. Among these, palladium (Pd) and platinum (Pt) are preferable from the viewpoint of oxidation activity, and rhodium (Rh) is preferable from the viewpoint of reduction activity. In the present embodiment, as described above, the catalyst layer 21 containing one or more kinds of catalyst metals in a mixed state is provided. In particular, the combined use of two or more kinds of catalytic metals is expected to have a synergistic effect due to having different catalytic activities.
このような触媒金属の組み合わせの態様は、特に制限されず、酸化活性に優れる二種以上の触媒金属の組み合わせ、還元活性に優れる二種以上の触媒金属の組み合わせ、酸化活性に優れる触媒金属と還元活性に優れる触媒金属の組み合わせが挙げられる。このなかでも、相乗効果の一つの態様として、酸化活性に優れる触媒金属と還元活性に優れる触媒金属の組み合わせが好ましく、Ｒｈ、Ｐｄ及びＲｈ、または、Ｐｔ及びＲｈを少なくとも含む組合せがより好ましい。このような組み合わせとすることにより、排ガス浄化性能がより向上する傾向にある。 The mode of the combination of such catalytic metals is not particularly limited, and a combination of two or more catalytic metals excellent in oxidation activity, a combination of two or more catalytic metals excellent in reduction activity, and a catalytic metal and reduction excellent in oxidation activity. A combination of catalytic metals having excellent activity may be mentioned. Among these, as one aspect of the synergistic effect, a combination of a catalytic metal excellent in oxidation activity and a catalytic metal excellent in reduction activity is preferable, and a combination containing at least Rh, Pd and Rh, or Pt and Rh is more preferable. By using such a combination, the exhaust gas purification performance tends to be further improved.
なお、触媒層２１が触媒金属を含有することは、排ガス浄化触媒の隔壁１３の断面の走査型電子顕微鏡などにより確認することができる。具体的には、走査型電子顕微鏡の視野においてエネルギー分散型Ｘ線分析を行うことにより確認することができる。 In addition, it can confirm that the catalyst layer 21 contains a catalyst metal with the scanning electron microscope etc. of the cross section of the partition 13 of an exhaust gas purification catalyst. Specifically, it can be confirmed by performing energy dispersive X-ray analysis in the field of view of a scanning electron microscope.
触媒層２１に含まれ、触媒金属を担持する担体粒子としては、従来この種の排ガス浄化触媒で使用される無機化合物を考慮することができる。例えば、酸化セリウム（セリア：ＣｅＯ2）、セリア−ジルコニア複合酸化物（ＣＺ複合酸化物）等の酸素吸蔵材（ＯＳＣ材）、酸化アルミニウム（アルミナ：Ａｌ2Ｏ3）、酸化ジルコニウム（ジルコニア：ＺｒＯ2）、酸化ケイ素（シリカ：ＳｉＯ2）、酸化チタン（チタニア：ＴｉＯ2）等の酸化物やこれらの酸化物を主成分とした複合酸化物を挙げることができる。これらは、ランタン、イットリウム等の希土類元素、遷移金属元素、アルカリ土類金属元素が添加された複合酸化物若しくは固溶体であってもよい。なお、これら担体粒子は、一種単独で用いても、二種以上を併用してもよい。ここで、酸素吸蔵材（ＯＳＣ材）とは、排ガスの空燃比がリーンであるとき（即ち酸素過剰側の雰囲気）には排ガス中の酸素を吸蔵し、排ガスの空燃比がリッチであるとき（即ち燃料過剰側の雰囲気）には吸蔵されている酸素を放出するものをいう。 As the carrier particles contained in the catalyst layer 21 and supporting the catalyst metal, inorganic compounds conventionally used in this type of exhaust gas purification catalyst can be considered. For example, oxygen storage materials (OSC materials) such as cerium oxide (ceria: CeO 2 ), ceria-zirconia composite oxide (CZ composite oxide), aluminum oxide (alumina: Al 2 O 3 ), zirconium oxide (zirconia: ZrO) 2 ), oxides such as silicon oxide (silica: SiO 2 ), titanium oxide (titania: TiO 2 ), and composite oxides mainly composed of these oxides. These may be complex oxides or solid solutions to which rare earth elements such as lanthanum and yttrium, transition metal elements, and alkaline earth metal elements are added. These carrier particles may be used alone or in combination of two or more. Here, the oxygen storage material (OSC material) means that oxygen in the exhaust gas is stored when the air-fuel ratio of the exhaust gas is lean (that is, the atmosphere on the oxygen excess side) and the air-fuel ratio of the exhaust gas is rich ( That is, the atmosphere on the excess fuel side) releases the stored oxygen.
なお、内燃機関、特にガソリンエンジンから排出される排ガスを浄化する排ガス浄化触媒であって、特に、粒子状物質の捕集用途に用いられるという観点から、排ガス浄化触媒１００の触媒層の塗工量（ウォールフロー型基材１Ｌあたりの触媒金属質量を除く触媒層の塗工量）は、好ましくは２０〜１１０ｇ／Ｌであり、より好ましくは４０〜９０ｇ／Ｌであり、さらに好ましくは５０〜７０ｇ／Ｌである。 In addition, it is an exhaust gas purification catalyst for purifying exhaust gas discharged from an internal combustion engine, particularly a gasoline engine, and particularly from the viewpoint of being used for collecting particulate matter, the coating amount of the catalyst layer of the exhaust gas purification catalyst 100 The coating amount of the catalyst layer excluding the catalyst metal mass per 1 L of the wall flow type substrate is preferably 20 to 110 g / L, more preferably 40 to 90 g / L, and further preferably 50 to 70 g. / L.
［排ガス浄化触媒の製造方法］
本実施形態の製造方法は、内燃機関であるガソリンエンジンから排出される排ガスを浄化する排ガス浄化触媒１００の製造方法であって、排ガス導入側の端部１１ａが開口した導入側セル１１と、該導入側セル１１に隣接し排ガス排出側の端部１２ａが開口した排出側セル１２とが、多孔質の隔壁１３により画定されたウォールフロー型基材１０を準備する工程Ｓ０と、ウォールフロー型基材１０の隔壁１３内の気孔表面上の少なくとも一部に、触媒スラリーを塗工して、触媒層２１を形成する触媒層形成工程Ｓ１と、を有し、該触媒層形成工程Ｓ１において、気孔径分布において、ウォールフロー型基材１０の隔壁１３のモード気孔径をＸとしたときに、触媒層２１が形成された隔壁１３のモード気孔径が０．６Ｘ以上０．９Ｘ以下であり、最小気孔径を１μｍとする気孔径分布において、ウォールフロー型基材１０の隔壁１３のＤ３０気孔径をＹとしたときに、触媒層２１が形成された隔壁１３のＤ３０気孔径が０．５５〜０．８０Ｙであり、ウォールフロー型基材１０の隔壁１３のＤ７０気孔径をＺとしたときに、触媒層２１が形成された隔壁１３のＤ７０気孔径が０．７０〜０．９０Ｚである排ガス浄化触媒１００を得ることを特徴とする。
[Method for producing exhaust gas purification catalyst]
The manufacturing method of the present embodiment is a manufacturing method of an exhaust gas purification catalyst 100 that purifies exhaust gas discharged from a gasoline engine that is an internal combustion engine, the introduction side cell 11 having an open end 11a on the exhaust gas introduction side, A step S0 in which a discharge-side cell 12 adjacent to the introduction-side cell 11 and having an open end 12a on the exhaust gas discharge side prepares a wall flow-type substrate 10 defined by a porous partition wall 13; A catalyst layer forming step S1 for forming a catalyst layer 21 by applying a catalyst slurry on at least a part of the pore surface in the partition wall 13 of the material 10, and in the catalyst layer forming step S1, In the pore size distribution, when the mode pore diameter of the partition wall 13 of the wall flow type substrate 10 is X, the mode pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.6X or more and 0.9X or less. In the pore size distribution in which the minimum pore size is 1 μm, when the D30 pore size of the partition wall 13 of the wall flow type substrate 10 is Y, the D30 pore size of the partition wall 13 on which the catalyst layer 21 is formed is 0.55 to 0.55. Exhaust gas in which the D70 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.70 to 0.90Z when the D70 pore diameter of the partition wall 13 of the wall flow type substrate 10 is Z. A purification catalyst 100 is obtained.
以下、各工程について説明する。なお、本明細書においては、触媒層２１を形成する前のウォールフロー型基材を「基材１０」と表記し、触媒層２１を形成した後のウォールフロー型基材を「排ガス浄化触媒１００」と表記する。 Hereinafter, each step will be described. In the present specification, the wall flow type base material before forming the catalyst layer 21 is referred to as “base material 10”, and the wall flow type base material after forming the catalyst layer 21 is referred to as “exhaust gas purification catalyst 100”. ".
＜準備工程＞
この準備工程Ｓ０では、基材として、上記排ガス浄化触媒１００において述べたウォールフロー型基材１０を準備する。
<Preparation process>
In this preparation step S0, the wall flow type substrate 10 described in the exhaust gas purification catalyst 100 is prepared as a substrate.
＜触媒層形成工程＞
この触媒層形成工程Ｓ１では、隔壁１３の気孔表面に触媒スラリーを塗工して、乾燥させ、焼成することで、触媒層２１を形成する。触媒スラリーの塗工方法は、特に制限されないが、例えば、基材１０の一部に触媒スラリーを含浸させて、それを基材１０の隔壁１３全体に広げる方法が挙げられる。より具体的には、排ガス導入側の端部１１ａ又は排ガス排出側の端部１２ａに、触媒スラリーを含浸させる含浸工程Ｓ１ａと、触媒スラリーを含浸させた端部側から基材１０内に気体を導入させることにより、基材１０に含浸された触媒スラリーを隔壁１３に塗工する塗工工程Ｓ１ｂを有する方法が挙げられる。
<Catalyst layer formation process>
In the catalyst layer forming step S1, the catalyst layer 21 is formed by applying a catalyst slurry to the pore surfaces of the partition walls 13, drying, and firing. The method for applying the catalyst slurry is not particularly limited, and examples thereof include a method in which a part of the base material 10 is impregnated with the catalyst slurry and is spread over the entire partition wall 13 of the base material 10. More specifically, impregnation step S1a in which the end portion 11a on the exhaust gas introduction side or the end portion 12a on the exhaust gas discharge side is impregnated with the catalyst slurry, and gas is introduced into the base material 10 from the end portion side impregnated with the catalyst slurry. Examples of the method include a coating step S1b in which the catalyst slurry impregnated in the base material 10 is applied to the partition wall 13 by introducing the catalyst slurry.
含浸工程Ｓ１ａにおける触媒スラリーの含浸方法としては、特に制限されないが、例えば、触媒スラリーに基材１０の端部を浸漬させる方法が挙げられる。この方法においては、必要に応じて、反対側の端部から気体を排出（吸引）させることにより触媒スラリーを引き上げてもよい。触媒スラリーを含浸させる端部は、排ガス導入側の端部１１ａ又は排ガス排出側の端部１２ａのどちらでもよいが、排ガス導入側の端部１１ａに触媒スラリーを含浸させることが好ましい。これにより、排ガスの導入方向と同じ方向で塗工工程Ｓ１ｂにおいて気体を導入することができ、複雑な気孔形状に対して、排ガスの流れに沿った形で触媒スラリーを塗工することができる。そのため、得られる排ガス浄化触媒の圧力損失の上昇抑制が見込まれ、また、排ガス浄化性能の向上も期待できる。 The method for impregnating the catalyst slurry in the impregnation step S1a is not particularly limited, and examples thereof include a method of immersing the end portion of the substrate 10 in the catalyst slurry. In this method, if necessary, the catalyst slurry may be pulled up by discharging (suctioning) gas from the opposite end. The end portion impregnated with the catalyst slurry may be either the end portion 11a on the exhaust gas introduction side or the end portion 12a on the exhaust gas discharge side, but it is preferable to impregnate the end portion 11a on the exhaust gas introduction side with the catalyst slurry. Thereby, gas can be introduce | transduced in coating process S1b in the same direction as the introduction direction of exhaust gas, and a catalyst slurry can be applied in the form along the flow of exhaust gas with respect to complicated pore shape. Therefore, increase suppression of pressure loss of the obtained exhaust gas purification catalyst is expected, and improvement of exhaust gas purification performance can be expected.
また、塗工工程Ｓ１ｂでは、触媒スラリーは、基材１０の導入側から奥へ気体Ｆの流れに沿って移動し、気体Ｆの排出側の端部へ到達する。その過程において、隔壁１３の気孔内部を触媒スラリーが通過することで、気孔内部に触媒スラリーを塗工することができ、隔壁の全体に触媒スラリーが塗工される。 Moreover, in coating process S1b, a catalyst slurry moves along the flow of the gas F from the introduction side of the base material 10 to the back, and reaches | attains the edge part by the side of discharge | emission of the gas F. In the process, the catalyst slurry passes through the pores of the partition walls 13 so that the catalyst slurry can be applied inside the pores, and the catalyst slurry is applied to the entire partition walls.
乾燥工程Ｓ１ｃでは、塗工した触媒スラリーを乾燥させる。乾燥工程Ｓ１ｃにおける乾燥条件は、触媒スラリーから溶媒が揮発するような条件であれば特に制限されない。例えば、乾燥温度は、好ましくは１００〜２２５℃であり、より好ましくは１００〜２００℃であり、さらに好ましくは１２５〜１７５℃である。また、乾燥時間は、好ましくは０．５〜２時間であり、好ましくは０．５〜１．５時間である。 In the drying step S1c, the coated catalyst slurry is dried. The drying conditions in the drying step S1c are not particularly limited as long as the solvent volatilizes from the catalyst slurry. For example, the drying temperature is preferably 100 to 225 ° C, more preferably 100 to 200 ° C, and further preferably 125 to 175 ° C. Moreover, drying time becomes like this. Preferably it is 0.5 to 2 hours, Preferably it is 0.5 to 1.5 hours.
焼成工程Ｓ１ｄでは、触媒スラリーを焼成して、触媒層２１を形成する。焼成工程Ｓ１ｄにおける焼成条件は、触媒スラリーから触媒層２１が形成できるような条件であれば特に制限されない。例えば、焼成温度は、特に制限されないが、好ましくは４００〜６５０℃であり、より好ましくは４５０〜６００℃であり、さらに好ましくは５００〜６００℃である。また、焼成時間は、好ましくは０．５〜２時間であり、好ましくは０．５〜１．５時間である。 In the firing step S1d, the catalyst slurry is fired to form the catalyst layer 21. The firing conditions in the firing step S1d are not particularly limited as long as the catalyst layer 21 can be formed from the catalyst slurry. For example, the firing temperature is not particularly limited, but is preferably 400 to 650 ° C, more preferably 450 to 600 ° C, and further preferably 500 to 600 ° C. Moreover, the firing time is preferably 0.5 to 2 hours, and preferably 0.5 to 1.5 hours.
なお、ガソリンエンジンから排出される排ガスを浄化する排ガス浄化触媒、特に、粒子状物質の捕集用途に用いられるという観点から、焼成工程Ｓ１ｄを経て得られる排ガス浄化触媒１００の触媒層の塗工量（ウォールフロー型基材１Ｌあたりの触媒金属質量を除く触媒層の塗工量）は、好ましくは２０〜１１０ｇ／Ｌであり、より好ましくは４０〜９０ｇ／Ｌであり、さらに好ましくは５０〜７０ｇ／Ｌである。 In addition, from the viewpoint of being used for an exhaust gas purification catalyst for purifying exhaust gas discharged from a gasoline engine, particularly for collecting particulate matter, the coating amount of the catalyst layer of the exhaust gas purification catalyst 100 obtained through the firing step S1d. The coating amount of the catalyst layer excluding the catalyst metal mass per 1 L of the wall flow type substrate is preferably 20 to 110 g / L, more preferably 40 to 90 g / L, and further preferably 50 to 70 g. / L.
（触媒スラリー）
触媒層２１を形成するための触媒スラリーについて説明する。触媒スラリーは、触媒粉体と、水などの溶剤とを含む。触媒粉体は、触媒金属粒子と該触媒金属粒子を担持する担体粒子とを含む、複数の触媒粒子の集団であり、後述する焼成工程を経て、触媒層２１を形成する。触媒粒子は、特に限定されず、公知の触媒粒子から適宜選択して用いることができる。なお、隔壁１３の気孔内への塗工性の観点から、触媒スラリーの固形分率は、好ましくは１〜５０質量％であり、より好ましくは１５〜４０質量％であり、さらに好ましくは２０〜３５質量％である。このような固形分率とすることにより、触媒スラリーを隔壁１３内の導入側セル１１側に塗工しやすくなる傾向にある。
(Catalyst slurry)
The catalyst slurry for forming the catalyst layer 21 will be described. The catalyst slurry contains catalyst powder and a solvent such as water. The catalyst powder is a group of a plurality of catalyst particles including catalyst metal particles and carrier particles supporting the catalyst metal particles, and forms the catalyst layer 21 through a firing step described later. The catalyst particles are not particularly limited, and can be appropriately selected from known catalyst particles. In addition, from a viewpoint of the coating property in the pores of the partition walls 13, the solid content of the catalyst slurry is preferably 1 to 50% by mass, more preferably 15 to 40% by mass, and further preferably 20 to 20%. 35% by mass. By setting it as such a solid content rate, it exists in the tendency which becomes easy to apply a catalyst slurry to the introduction side cell 11 side in the partition 13.
触媒スラリーに含まれる触媒粉体のＤ９０粒子径は、好ましくは１〜７μｍであり、より好ましくは１〜５μｍであり、さらに好ましくは１〜３μｍである。Ｄ９０粒子径が１μｍ以上であることにより、触媒粉体をミリング装置で破砕する場合の粉砕時間を短縮することができ、作業効率がより向上する傾向にある。また、Ｄ９０粒子径が７μｍ以下であることにより、粗大粒子が隔壁１３内の気孔を閉塞することが抑制され、圧力損失の上昇が抑制される傾向にある。なお、本明細書において、Ｄ９０粒子径は、レーザー回折式粒子径分布測定装置（例えば、島津製作所社製、レーザー回折式粒子径分布測定装置ＳＡＬＤ−３１００等）で測定することができる。 The D90 particle size of the catalyst powder contained in the catalyst slurry is preferably 1 to 7 μm, more preferably 1 to 5 μm, and further preferably 1 to 3 μm. When the D90 particle size is 1 μm or more, the pulverization time when the catalyst powder is crushed with a milling device can be shortened, and the working efficiency tends to be further improved. Further, when the D90 particle diameter is 7 μm or less, the coarse particles are suppressed from blocking the pores in the partition wall 13 and the increase in pressure loss tends to be suppressed. In the present specification, the D90 particle size can be measured with a laser diffraction particle size distribution measuring device (for example, a laser diffraction particle size distribution measuring device SALD-3100 manufactured by Shimadzu Corporation).
触媒スラリーに含まれる触媒金属としては、特に制限されず、種々の酸化触媒や還元触媒として機能し得る金属種を用いることができる。例えば、白金（Ｐｔ）、パラジウム（Ｐｄ）、ロジウム（Ｒｈ）、ルテニウム（Ｒｕ）、イリジウム（Ｉｒ）及びオスミウム（Ｏｓ）等の白金族金属が挙げられる。このなかでも、酸化活性の観点からはパラジウム（Ｐｄ）、白金（Ｐｔ）が好ましく、還元活性の観点からはロジウム（Ｒｈ）が好ましい。 The catalyst metal contained in the catalyst slurry is not particularly limited, and metal species that can function as various oxidation catalysts and reduction catalysts can be used. For example, platinum group metals such as platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir), and osmium (Os) can be used. Among these, palladium (Pd) and platinum (Pt) are preferable from the viewpoint of oxidation activity, and rhodium (Rh) is preferable from the viewpoint of reduction activity.
触媒金属粒子を担持する担体粒子としては、従来この種の排ガス浄化触媒で使用される無機化合物を考慮することができる。例えば、酸化セリウム（セリア：ＣｅＯ2）、セリア−ジルコニア複合酸化物（ＣＺ複合酸化物）等の酸素吸蔵材（ＯＳＣ材）、酸化アルミニウム（アルミナ：Ａｌ2Ｏ3）、酸化ジルコニウム（ジルコニア：ＺｒＯ2）、酸化ケイ素（シリカ：ＳｉＯ2）、酸化チタン（チタニア：ＴｉＯ2）等の酸化物やこれらの酸化物を主成分とした複合酸化物を挙げることができる。これらは、ランタン、イットリウム等の希土類元素、遷移金属元素、アルカリ土類金属元素が添加された複合酸化物若しくは固溶体であってもよい。なお、これら担体粒子は、一種単独で用いても、二種以上を併用してもよい。ここで、酸素吸蔵材（ＯＳＣ材）とは、排ガスの空燃比がリーンであるとき（即ち酸素過剰側の雰囲気）には排ガス中の酸素を吸蔵し、排ガスの空燃比がリッチであるとき（即ち燃料過剰側の雰囲気）には吸蔵されている酸素を放出するものをいう。なお、排ガス浄化性能の観点から、触媒スラリーに含まれる担体粒子の比表面積は、好ましくは１０〜５００ｍ2／ｇ、より好ましくは３０〜２００ｍ2／ｇである。 As the carrier particles supporting the catalytic metal particles, inorganic compounds conventionally used in this type of exhaust gas purification catalyst can be considered. For example, oxygen storage materials (OSC materials) such as cerium oxide (ceria: CeO 2 ), ceria-zirconia composite oxide (CZ composite oxide), aluminum oxide (alumina: Al 2 O 3 ), zirconium oxide (zirconia: ZrO) 2 ), oxides such as silicon oxide (silica: SiO 2 ), titanium oxide (titania: TiO 2 ), and composite oxides mainly composed of these oxides. These may be complex oxides or solid solutions to which rare earth elements such as lanthanum and yttrium, transition metal elements, and alkaline earth metal elements are added. These carrier particles may be used alone or in combination of two or more. Here, the oxygen storage material (OSC material) means that oxygen in the exhaust gas is stored when the air-fuel ratio of the exhaust gas is lean (that is, the atmosphere on the oxygen excess side) and the air-fuel ratio of the exhaust gas is rich ( That is, the atmosphere on the excess fuel side) releases the stored oxygen. From the viewpoint of exhaust gas purification performance, the specific surface area of the carrier particles contained in the catalyst slurry is preferably 10 to 500 m 2 / g, more preferably 30 to 200 m 2 / g.
本実施形態においては、上記塗工工程Ｓ１ｂから焼成工程Ｓ１ｄにおいて、ススが通過しやすい大径の気孔を減少させるとともに、スス捕集に適した小径の気孔を減少させないような触媒層を形成することにより、ウォールフロー型基材１０の隔壁１３のモード気孔径をＸとしたときに、触媒層２１が形成された隔壁１３のモード気孔径が０．６Ｘ以上０．９Ｘ以下であり、最小気孔径を１μｍとする気孔径分布において、ウォールフロー型基材１０の隔壁のＤ３０気孔径をＹとしたときに、触媒層２１が形成された隔壁１３のＤ３０気孔径が０．５５〜０．８０Ｙであり、ウォールフロー型基材１０の隔壁１３のＤ７０気孔径をＺとしたときに、触媒層２１が形成された隔壁１３のＤ７０気孔径が０．７０〜０．９０Ｚである排ガス浄化触媒１００を得る。触媒スラリーは、その粘度や表面張力に応じて、毛細管現象により小径の気孔に浸入した状態で乾燥しやすい性質や、小径の気孔に浸入しにくい性質など種々の性質を取り得る。ここで、小径の気孔に集中して浸入しにくい物性を有する触媒スラリーを用いることにより、大径の気孔においては触媒層２１に形成により気孔径を小径化することができ、ススが通過しやすい大径の気孔を減少させるとともに、小径の気孔においては、触媒層２１の形成による閉塞を抑制し、気孔閉塞によりスス捕集に適した小径の気孔が減少することを抑制することができる。 In the present embodiment, in the coating step S1b to the firing step S1d, a catalyst layer is formed that reduces large-diameter pores through which soot easily passes and does not reduce small-diameter pores suitable for soot collection. Thus, when the mode pore diameter of the partition wall 13 of the wall flow type substrate 10 is X, the mode pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.6X or more and 0.9X or less, and the minimum pore size In the pore size distribution in which the pore size is 1 μm, when the D30 pore size of the partition wall of the wall flow type substrate 10 is Y, the D30 pore size of the partition wall 13 on which the catalyst layer 21 is formed is 0.55 to 0.80 Y. The exhaust gas purification catalyst in which the D70 pore diameter of the partition wall 13 on which the catalyst layer 21 is formed is 0.70 to 0.90 Z, where Z is the D70 pore diameter of the partition wall 13 of the wall flow type substrate 10. Get the 100. Depending on its viscosity and surface tension, the catalyst slurry can have various properties such as a property of being easily dried in a state where it has entered into small pores by capillary action and a property of being difficult to enter into the small pores. Here, by using a catalyst slurry having physical properties that are difficult to enter by concentrating on the small-diameter pores, the pore diameter can be reduced by forming in the catalyst layer 21 in the large-diameter pores, and soot easily passes. In addition to reducing the large-diameter pores, the small-diameter pores can be prevented from being blocked by the formation of the catalyst layer 21, and the small-diameter pores suitable for soot collection can be prevented from being reduced due to the pores being blocked.
［用途］
内燃機関（エンジン）には、酸素と燃料ガスとを含む混合気が供給され、この混合気が燃焼されて、燃焼エネルギーが力学的エネルギーに変換される。このときに燃焼された混合気は排ガスとなって排気系に排出される。排気系には、排ガス浄化触媒を備える排ガス浄化装置が設けられており、排ガス浄化触媒により排ガスに含まれる有害成分（例えば、一酸化炭素（ＣＯ）、炭化水素（ＨＣ）、窒素酸化物（ＮＯｘ））が浄化されるとともに、排ガスに含まれる粒子状物質（ＰＭ）が捕集され、除去される。特に、本実施形態の排ガス浄化触媒１００は、ガソリンエンジンの排ガスに含まれる粒子状物質を捕集し、除去できるガソリンパティキュレートフィルタ（ＧＰＦ）に用いられるものであることが好ましい。
[Usage]
An internal combustion engine (engine) is supplied with an air-fuel mixture containing oxygen and fuel gas, and the air-fuel mixture is combusted to convert combustion energy into mechanical energy. The air-fuel mixture combusted at this time becomes exhaust gas and is discharged to the exhaust system. The exhaust system is provided with an exhaust gas purification device including an exhaust gas purification catalyst, and harmful components (for example, carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NOx) contained in the exhaust gas by the exhaust gas purification catalyst are provided. )) Is purified, and particulate matter (PM) contained in the exhaust gas is collected and removed. In particular, the exhaust gas purification catalyst 100 of this embodiment is preferably used for a gasoline particulate filter (GPF) that can collect and remove particulate matter contained in exhaust gas of a gasoline engine.
以下に試験例、実施例と比較例を挙げて本発明の特徴をさらに具体的に説明するが、本発明は、これらによりなんら限定されるものではない。すなわち、以下の実施例に示す材料、使用量、割合、処理内容、処理手順等は、本発明の趣旨を逸脱しない限り、適宜変更することができる。また、以下の実施例における各種の製造条件や評価結果の値は、本発明の実施態様における好ましい上限値又は好ましい下限値としての意味をもつものであり、好ましい範囲は前記した上限又は下限の値と、下記実施例の値又は実施例同士の値との組み合わせで規定される範囲であってもよい。 Hereinafter, the features of the present invention will be described more specifically with reference to test examples, examples and comparative examples, but the present invention is not limited thereto. That is, the materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. In addition, various production conditions and evaluation result values in the following examples have a meaning as a preferable upper limit value or a preferable lower limit value in the embodiment of the present invention, and a preferable range is the above-described upper limit or lower limit value. And a range defined by a combination of values of the following examples or values of the examples.
（実施例１）
アルミナ粉末およびジルコニア粉末およびセリアジルコニア複合酸化物粉末に、硝酸パラジウム水溶液を含浸させ、その後、５００℃で１時間焼成して、Ｐｄ担持粉末を得た。また、アルミナ粉末およびジルコニア粉末に、硝酸ロジウム水溶液を含浸させ、その後、５００℃で１時間焼成して、Ｒｈ担持粉末を得た。
Example 1
Alumina powder, zirconia powder, and ceria zirconia composite oxide powder were impregnated with an aqueous palladium nitrate solution and then fired at 500 ° C. for 1 hour to obtain a Pd-supported powder. Further, an alumina powder and a zirconia powder were impregnated with an aqueous rhodium nitrate solution, and then fired at 500 ° C. for 1 hour to obtain an Rh-supported powder.
得られたＰｄ担持粉末４８０ｇ及びＲｈ担持粉末３９０ｇと、セリアジルコニア複合酸化物粉末９５ｇと、イオン交換水とを混合し、得られた混合物をボールミルに投入し、触媒粉体が所定の粒子径分布になるまでミリングし、Ｄ９０粒子径が３．０μｍである触媒スラリーを得た。得られた触媒スラリーに、水酸化バリウム八水和物２９ｇと、６０％硝酸とを混合し、ｐＨが６．７の触媒スラリーを得た。 480 g of the obtained Pd-supported powder and 390 g of Rh-supported powder, 95 g of ceria zirconia composite oxide powder, and ion-exchanged water are mixed, and the resulting mixture is put into a ball mill so that the catalyst powder has a predetermined particle size distribution. To obtain a catalyst slurry having a D90 particle size of 3.0 μm. The resulting catalyst slurry was mixed with 29 g of barium hydroxide octahydrate and 60% nitric acid to obtain a catalyst slurry having a pH of 6.7.
次いで、コージェライト製のウォールフロー型ハニカム基材（セル数／ミル厚：３００ｃｐｓｉ／８．５ｍｉｌ、直径：１１８．４ｍｍ、全長：１２７ｍｍ、モード気孔径Ｘ：２０μｍ、気孔率：６５％）を用意した。この基材の排ガス導入側の端部を触媒スラリーに浸漬させ、反対側の端部側から減圧吸引して、基材端部に触媒スラリーを含浸保持させた。排ガス導入側の端部から基材内へ気体を流入させて、隔壁内の気孔表面に触媒スラリーを塗工するとともに、基材の排ガス排出側の端部から過剰分の触媒スラリーを吹き払って、気体の流入を停止した。その後、触媒スラリーを塗工した基材を１５０℃で乾燥させた後、大気雰囲気下、５５０℃で焼成して、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり５９．１ｇ（白金族金属の重量を除く）であった。 Next, a cordierite wall flow type honeycomb substrate (cell number / mil thickness: 300 cpsi / 8.5 mil, diameter: 118.4 mm, total length: 127 mm, mode pore diameter X: 20 μm, porosity: 65%) is prepared. did. The end of the base material on the exhaust gas introduction side was immersed in the catalyst slurry, and suctioned under reduced pressure from the end portion on the opposite side, so that the end of the base material was impregnated and held. Gas is allowed to flow into the base material from the end on the exhaust gas introduction side, and catalyst slurry is applied to the pore surfaces in the partition walls, and excess catalyst slurry is blown off from the end on the exhaust gas discharge side of the base material. The gas flow was stopped. Thereafter, the substrate coated with the catalyst slurry was dried at 150 ° C., and then fired at 550 ° C. in an air atmosphere to produce an exhaust gas purification catalyst. In addition, the coating amount of the catalyst layer after firing was 59.1 g (excluding the weight of the platinum group metal) per liter of the base material.
（実施例２）
硝酸パラジウム水溶液をアルミナ粉末に含侵して、Ｐｄ担持粉末を得た。また、硝酸ロジウム水溶液をアルミナ粉末に含浸して、Ｒｈ担持粉末を得た。得られたＰｄ担持粉末およびＲｈ担持粉末にセリアジルコニア複合酸化物粉末と、４６％硝酸ランタン水溶液と、イオン交換水とを混合したこと以外は、実施例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６０．９ｇ（白金族金属の重量を除く）であった。
(Example 2)
An aqueous palladium nitrate solution was impregnated into the alumina powder to obtain a Pd-supported powder. In addition, an alumina powder was impregnated with an aqueous rhodium nitrate solution to obtain an Rh-supported powder. An exhaust gas purification catalyst was produced in the same manner as in Example 1 except that the obtained Pd-supported powder and Rh-supported powder were mixed with ceria zirconia composite oxide powder, 46% lanthanum nitrate aqueous solution, and ion-exchanged water. did. The coating amount of the catalyst layer after firing was 60.9 g (excluding the weight of the platinum group metal) per liter of the base material.
（実施例３）
得られた触媒スラリーに、炭酸アンモニウム４４．９ｇ（ｐＨ調整剤）を混合し、ｐＨが５．１の触媒スラリーを得たこと以外は、実施例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６０．０ｇ（白金族金属の重量を除く）であった。
(Example 3)
An exhaust gas purification catalyst was produced in the same manner as in Example 1 except that 44.9 g of ammonium carbonate (pH adjuster) was mixed with the obtained catalyst slurry to obtain a catalyst slurry having a pH of 5.1. . The coating amount of the catalyst layer after firing was 60.0 g (excluding the weight of the platinum group metal) per liter of the base material.
（実施例４）
硝酸パラジウム水溶液をアルミナ粉末およびセリアジルコニア複合酸化物粉末に含侵させて、Ｐｄ担持粉末を得た。また、硝酸ロジウム水溶液をアルミナ粉末およびセリアジルコニア複合酸化物粉末に含侵させて、Ｒｈ担持粉末を得た。得られたＰｄ担持粉末およびＲｈ担持粉末を用いて調製した触媒スラリーに、炭酸アンモニウム３３ｇ（ｐＨ調整剤）を混合し、ｐＨが５．１の触媒スラリーを得たこと以外は、実施例２と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６２．０ｇ（白金族金属の重量を除く）であった。
Example 4
An aqueous palladium nitrate solution was impregnated with alumina powder and ceria zirconia composite oxide powder to obtain Pd-supported powder. Further, an rhodium nitrate aqueous solution was impregnated with the alumina powder and the ceria zirconia composite oxide powder to obtain a Rh-supported powder. The catalyst slurry prepared using the obtained Pd-supported powder and Rh-supported powder was mixed with 33 g of ammonium carbonate (pH adjuster) to obtain a catalyst slurry having a pH of 5.1. Similarly, an exhaust gas purification catalyst was produced. The coating amount of the catalyst layer after firing was 62.0 g (excluding the weight of the platinum group metal) per liter of the base material.
（実施例５）
硝酸パラジウム水溶液をアルミナ粉末およびセリアジルコニア複合酸化物粉末に含侵して、Ｐｄ担持粉末を得た。また、硝酸ロジウム水溶液をジルコニア粉末に含侵して、Ｒｈ担持粉末を得た。得られたＰｄ担持粉末及びＲｈ担持粉末と、セリアジルコニア複合酸化物粉末と、４６％硝酸ランタン水溶液と、イオン交換水とを混合し、得られた触媒スラリーに、水酸化バリウム八水和物９６ｇと炭酸アンモニウム２７ｇ（ｐＨ調整剤）を混合し、ｐＨが５．５の触媒スラリーを得たこと以外は、実施例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６１．８ｇ（白金族金属の重量を除く）であった。
(Example 5)
An aqueous palladium nitrate solution was impregnated with the alumina powder and the ceria zirconia composite oxide powder to obtain a Pd-supported powder. Moreover, the rhodium nitrate aqueous solution was impregnated with the zirconia powder to obtain an Rh-supported powder. The obtained Pd-supported powder and Rh-supported powder, ceria zirconia composite oxide powder, 46% lanthanum nitrate aqueous solution, and ion-exchanged water were mixed, and the resulting catalyst slurry was mixed with 96 g of barium hydroxide octahydrate. And 27 g of ammonium carbonate (pH adjuster) were mixed, and an exhaust gas purification catalyst was produced in the same manner as in Example 1 except that a catalyst slurry having a pH of 5.5 was obtained. The coating amount of the catalyst layer after firing was 61.8 g (excluding the weight of the platinum group metal) per liter of the base material.
（比較例１）
触媒スラリーの調製において、触媒スラリーに、水酸化バリウム八水和物と、６０％硝酸とを混合しなかったこと以外は、実施例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６０．０ｇ（白金族金属の重量を除く）であった。
(Comparative Example 1)
In the preparation of the catalyst slurry, an exhaust gas purification catalyst was produced in the same manner as in Example 1, except that the catalyst slurry was not mixed with barium hydroxide octahydrate and 60% nitric acid. The coating amount of the catalyst layer after firing was 60.0 g (excluding the weight of the platinum group metal) per liter of the base material.
（比較例２）
触媒スラリーの調製において、触媒スラリーに、水酸化バリウム八水和物と、６０％硝酸とを混合しなかったこと以外は、実施例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６０．９ｇ（白金族金属の重量を除く）であった。
(Comparative Example 2)
In the preparation of the catalyst slurry, an exhaust gas purification catalyst was produced in the same manner as in Example 1, except that the catalyst slurry was not mixed with barium hydroxide octahydrate and 60% nitric acid. The coating amount of the catalyst layer after firing was 60.9 g (excluding the weight of the platinum group metal) per liter of the base material.
（比較例３）
硝酸パラジウム水溶液をアルミナ粉末およびセリアジルコニア複合酸化物粉末に含侵させて、Ｐｄ担持粉末を得た。また、硝酸ロジウム水溶液をセリアジルコニア複合酸化物粉末に含侵させて、Ｒｈ担持粉末を得た。得られたＰｄ担持粉末およびＲｈ担持粉末と、硫酸バリウム粉末と、イオン交換水とを混合したこと以外は、比較例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６０．０ｇ（白金族金属の重量を除く）であった。
(Comparative Example 3)
An aqueous palladium nitrate solution was impregnated with alumina powder and ceria zirconia composite oxide powder to obtain Pd-supported powder. Further, a rhodium nitrate aqueous solution was impregnated with the ceria zirconia composite oxide powder to obtain an Rh-supported powder. An exhaust gas purification catalyst was produced in the same manner as in Comparative Example 1 except that the obtained Pd-supported powder and Rh-supported powder, barium sulfate powder, and ion-exchanged water were mixed. The coating amount of the catalyst layer after firing was 60.0 g (excluding the weight of the platinum group metal) per liter of the base material.
（比較例４）
硝酸パラジウム水溶液をセリアジルコニア複合酸化物粉末に含侵させて、Ｐｄ担持粉末を得た。また、硝酸ロジウム水溶液をジルコニア粉末に含侵して、Ｒｈ担持粉末を得た。得られたＰｄ担持粉末およびＲｈ担持粉末を用いて触媒スラリーを調製したこと以外は、比較例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６０．９ｇ（白金族金属の重量を除く）であった。
(Comparative Example 4)
An aqueous palladium nitrate solution was impregnated with the ceria zirconia composite oxide powder to obtain a Pd-supported powder. Moreover, the rhodium nitrate aqueous solution was impregnated with the zirconia powder to obtain an Rh-supported powder. An exhaust gas purification catalyst was produced in the same manner as in Comparative Example 1 except that a catalyst slurry was prepared using the obtained Pd-supported powder and Rh-supported powder. The coating amount of the catalyst layer after firing was 60.9 g (excluding the weight of the platinum group metal) per liter of the base material.
（比較例５）
硝酸パラジウム水溶液をセリアジルコニア複合酸化物粉末に含侵させて、Ｐｄ担持粉末を得た。また、硝酸ロジウム水溶液をアルミナ粉末に含侵して、Ｒｈ担持粉末を得た。得られたＰｄ担持粉末およびＲｈ担持粉末を用いて触媒スラリーを調製した以外は、比較例１と同様にして、排ガス浄化触媒を作製した。なお、焼成後における触媒層の塗工量は、基材１Ｌ当たり６０．９ｇ（白金族金属の重量を除く）であった。
(Comparative Example 5)
An aqueous palladium nitrate solution was impregnated with the ceria zirconia composite oxide powder to obtain a Pd-supported powder. Moreover, the rhodium nitrate aqueous solution was impregnated with the alumina powder to obtain an Rh-supported powder. An exhaust gas purification catalyst was produced in the same manner as in Comparative Example 1 except that a catalyst slurry was prepared using the obtained Pd-supported powder and Rh-supported powder. The coating amount of the catalyst layer after firing was 60.9 g (excluding the weight of the platinum group metal) per liter of the base material.
［粒子径分布測定］
触媒スラリーのＤ９０粒子径は、島津製作所社製レーザー回折式粒子径分布測定装置ＳＡＬＤ−３１００を用いて、レーザー散乱法により測定した。
[Particle size distribution measurement]
The D90 particle size of the catalyst slurry was measured by a laser scattering method using a laser diffraction particle size distribution analyzer SALD-3100 manufactured by Shimadzu Corporation.
［水銀圧入法］
実施例及び比較例で作製した排ガス浄化触媒、並びに、触媒スラリーを塗工する前の基材の、排ガス導入側部分、排ガス排出側部分、及び中間部分の各隔壁から、モード気孔径、Ｄ３０気孔径、Ｄ７０気孔径、及び気孔容積の測定用サンプル（１ｃｍ3）をそれぞれ採取した。測定用サンプルを乾燥後、水銀ポロシメーター（Ｔｈｅｒｍｏ Ｆｉｓｈｅｒ Ｓｃｉｅｎｔｉｆｉｃ社製、商品名：ＰＡＳＣＡＬ１４０及びＰＡＳＣＡＬ４４０）を用いて、水銀圧入法により気孔分布を測定した。この際、ＰＡＳＣＡＬ１４０により低圧領域（０〜４００Ｋｐａ）を測定し、ＰＡＳＣＡＬ４４０により高圧領域（０．１Ｍｐａ〜４００Ｍｐａ）を測定した。得られた気孔分布から、モード気孔径、Ｄ３０気孔径、Ｄ７０気孔径、を求め、また、気孔径１μｍ以上の気孔における気孔容積を算出した。なお、気孔径及び気孔容積の値としては、排ガス導入側部分、排ガス排出側部分、及び中間部分それぞれで得られた値の平均値を採用した。
[Mercury intrusion method]
From the partition walls of the exhaust gas purification catalyst prepared in Examples and Comparative Examples, and the exhaust gas introduction side portion, the exhaust gas discharge side portion, and the intermediate portion of the base material before applying the catalyst slurry, the mode pore diameter, D30 gas Samples for measuring pore diameter, D70 pore diameter, and pore volume (1 cm 3 ) were collected. After the measurement sample was dried, the pore distribution was measured by mercury porosimetry using a mercury porosimeter (manufactured by Thermo Fisher Scientific, trade names: PASCAL 140 and PASCAL 440). At this time, the low pressure region (0 to 400 Kpa) was measured by PASCAL140, and the high pressure region (0.1 Mpa to 400 Mpa) was measured by PASCAL440. From the obtained pore distribution, the mode pore diameter, D30 pore diameter, and D70 pore diameter were determined, and the pore volume of pores having a pore diameter of 1 μm or more was calculated. In addition, as the value of the pore diameter and the pore volume, average values of values obtained in the exhaust gas introduction side portion, the exhaust gas discharge side portion, and the intermediate portion were adopted.
次いで、下記式により、実施例及び比較例で作製した排ガス浄化触媒の気孔率を算出した。その結果を、下記表１に示す。また、図２に、実施例及び比較例の気孔容積分布を示す。
排ガス浄化触媒の気孔率（％）＝触媒層が形成された隔壁の気孔容積（ｃｃ／ｇ）÷基材の気孔容積（ｃｃ／ｇ）×基材の気孔率（％）
基材の気孔率（％）＝６５％
Next, the porosity of the exhaust gas purification catalyst produced in the examples and comparative examples was calculated by the following formula. The results are shown in Table 1 below. FIG. 2 shows the pore volume distributions of the examples and comparative examples.
Porosity of exhaust gas purification catalyst (%) = Pore volume of partition wall in which catalyst layer is formed (cc / g) ÷ Pore volume of substrate (cc / g) x Porosity of substrate (%)
Substrate porosity (%) = 65%
［スス捕集性能の測定］
ガソリンエンジンにおけるＰＮ規制を前提として、スス捕集性能の測定を行った。具体的には、実施例及び比較例で作製した排ガス浄化触媒を、１．５Ｌ直噴ターボエンジン搭載車に取り付け、固体粒子数測定装置（堀場製作所製、商品名：ＭＥＸＡ−２１００ ＳＰＣＳ）を用いて、ＷＬＴＣモード走行時のスス排出数量（ＰＮtest）を測定した。なお、ススの捕集率は、排ガス浄化触媒を搭載せずに上記試験を行った際に測定したスス量（ＰＮblank）からの減少率として、下記式により算出した。その結果を、下記表１に示す。
ススの捕集率（％）＝（ＰＮblank−ＰＮtest）／ＰＮblank × １００（％）
[Measurement of soot collection performance]
Soot collection performance was measured on the premise of PN regulations for gasoline engines. Specifically, the exhaust gas purification catalyst produced in the examples and comparative examples is attached to a vehicle equipped with a 1.5 L direct injection turbo engine, and a solid particle number measuring device (manufactured by Horiba, trade name: MEXA-2100 SPCS) is used. Then, the soot discharge quantity (PN test ) at the time of running in the WLTC mode was measured. The soot collection rate was calculated by the following formula as a reduction rate from the soot amount (PN blank ) measured when the above test was conducted without mounting the exhaust gas purification catalyst. The results are shown in Table 1 below.
Soot collection rate (%) = (PN blank -PN test ) / PN blank x 100 (%)
その結果を、実施例及び比較例における、気孔狭小率（ウォールフロー型基材の隔壁のモード気孔径に対する、触媒層が形成された隔壁のモード気孔径の割合）とスス捕集率との関係としてまとめて図３に示す。図３に示されるように、気孔狭小率とスス捕集率との間には、相関関係が認められる。 The relationship between the porosity narrowing ratio (the ratio of the mode pore diameter of the partition wall on which the catalyst layer was formed to the mode pore diameter of the partition wall of the wall flow type substrate) and the soot collection rate in the examples and comparative examples. Are collectively shown in FIG. As shown in FIG. 3, a correlation is observed between the pore narrowing rate and the soot collection rate.
［圧力損失の測定］
実施例及び比較例で作製した排ガス浄化触媒、並びに、触媒スラリーを塗布する前の基材を圧力損失測定装置（ツクバリカセイキ株式会社製）にそれぞれ設置し、設置した排ガス浄化触媒に室温の空気を導入させた。排ガス浄化触媒からの空気の排出量が４ｍ3／ｍｉｎとなったときの空気の導入側と排出側の差圧を測定して得られた値を、排ガス浄化触媒の圧力損失とした。その結果を、下記表１に示す。
[Measurement of pressure loss]
Exhaust gas purification catalysts prepared in the examples and comparative examples, and the base material before applying the catalyst slurry were installed in a pressure loss measuring device (manufactured by Tsukubarika Seiki Co., Ltd.), and air at room temperature was installed in the installed exhaust gas purification catalyst. Was introduced. The value obtained by measuring the differential pressure between the air introduction side and the exhaust side when the amount of air discharged from the exhaust gas purification catalyst reached 4 m 3 / min was taken as the pressure loss of the exhaust gas purification catalyst. The results are shown in Table 1 below.
本発明の排ガス浄化触媒は、ガソリンエンジンの排ガス中に含まれる粒子状物質を除去するため排ガス浄化触媒として広く且つ有効に利用することができる。また、本発明の排ガス浄化触媒は、ガソリンエンジンのみならず、ジェットエンジン、ボイラー、ガスタービン等の排ガス中に含まれる粒子状物質を除去するため排ガス浄化触媒としても有効に利用可能である。 The exhaust gas purification catalyst of the present invention can be widely and effectively used as an exhaust gas purification catalyst because it removes particulate matter contained in the exhaust gas of a gasoline engine. Further, the exhaust gas purification catalyst of the present invention can be effectively used as an exhaust gas purification catalyst because it removes particulate matter contained in exhaust gas of not only gasoline engines but also jet engines, boilers, gas turbines and the like.
１０ ・・・ウォールフロー型基材
１１ ・・・導入側セル
１１ａ・・・排ガス導入側の端部
１２ ・・・排出側セル
１２ａ・・・排ガス排出側の端部
１３ ・・・隔壁
２１ ・・・触媒層
１００ ・・・排ガス浄化触媒
DESCRIPTION OF SYMBOLS 10 ... Wall flow type base material 11 ... Introduction side cell 11a ... End part by the side of exhaust gas introduction 12 ... Discharge side cell 12a ... End part by the side of exhaust gas discharge 13 ... Partition 21 ..Catalyst layer 100 ... Exhaust gas purification catalyst
Claims (5)
排ガス導入側の端部が開口した導入側セルと、該導入側セルに隣接し排ガス排出側の端部が開口した排出側セルとが、多孔質の隔壁により画定されたウォールフロー型基材と、
前記隔壁の気孔内に形成された触媒層と、を有し、
気孔径分布において、前記ウォールフロー型基材の前記隔壁のモード気孔径をＸとしたときに、前記触媒層が形成された前記隔壁のモード気孔径が０．６Ｘ以上０．９Ｘ以下であり、
最小気孔径を１μｍとする気孔径分布において、
前記ウォールフロー型基材の隔壁のＤ３０気孔径をＹとしたときに、前記触媒層が形成された前記隔壁のＤ３０気孔径が０．６９〜０．８０Ｙであり、
前記ウォールフロー型基材の隔壁のＤ７０気孔径をＺとしたときに、前記触媒層が形成された前記隔壁のＤ７０気孔径が０．８０〜０．９０Ｚであり、
前記モード気孔径の狭小率ＮＲ M に対する前記Ｄ３０気孔径の狭小率ＮＲ D30 の比率（ＮＲ D30 ／ＮＲ M ）が、０．８７〜０．９５である、
排ガス浄化触媒。 An exhaust gas purification catalyst for purifying exhaust gas discharged from a gasoline engine,
A wall flow type substrate in which an introduction side cell having an open end on the exhaust gas introduction side and an exhaust side cell having an open end on the exhaust gas discharge side adjacent to the introduction side cell are defined by a porous partition; ,
A catalyst layer formed in the pores of the partition wall,
In the pore diameter distribution, when the mode pore diameter of the partition wall of the wall flow type substrate is X, the mode pore diameter of the partition wall on which the catalyst layer is formed is 0.6X or more and 0.9X or less,
In the pore size distribution with a minimum pore size of 1 μm,
When the D30 pore diameter of the partition wall of the wall flow type substrate is Y, the D30 pore diameter of the partition wall on which the catalyst layer is formed is 0.69 to 0.80Y,
When the D70 pore diameter of the partition wall of the wall flow type substrate is Z, the D70 pore diameter of the partition wall on which the catalyst layer is formed is 0.80 to 0.90 Z,
Said mode pore diameter of the narrowing ratio NR ratio of the D30 narrowing ratio of pore diameter NR D30 for M (NR D30 / NR M) is Ru der 0.87 to 0.95,
Exhaust gas purification catalyst.
請求項１に記載の排ガス浄化触媒。 The mode pore diameter X of the partition wall of the wall flow type substrate is 10 to 30 μm.
The exhaust gas purification catalyst according to claim 1.
請求項１又は２に記載の排ガス浄化触媒。 The mode pore diameter of the partition wall on which the catalyst layer is formed is 0.65X or more and 0.89X or less.
The exhaust gas purification catalyst according to claim 1 or 2.
請求項１〜３のいずれか一項に記載の排ガス浄化触媒。 The porosity of the partition walls of the wall flow type substrate is 60 to 70%.
The exhaust gas purification catalyst according to any one of claims 1 to 3.
排ガス導入側の端部が開口した導入側セルと、該導入側セルに隣接し排ガス排出側の端部が開口した排出側セルとが、多孔質の隔壁により画定されたウォールフロー型基材を準備する工程と、
前記ウォールフロー型基材の前記隔壁内の気孔表面上の少なくとも一部に、触媒スラリーを塗工して、触媒層を形成する触媒層形成工程と、を有し、
該触媒層形成工程において、気孔径分布において、前記ウォールフロー型基材の隔壁のモード気孔径をＸとしたときに、前記触媒層が形成された前記隔壁のモード気孔径が０．６Ｘ以上０．９Ｘ以下であり、最小気孔径を１μｍとする気孔径分布において、前記ウォールフロー型基材の隔壁のＤ３０気孔径をＹとしたときに、前記触媒層が形成された前記隔壁のＤ３０気孔径が０．６９〜０．８０Ｙであり、前記ウォールフロー型基材の隔壁のＤ７０気孔径をＺとしたときに、前記触媒層が形成された前記隔壁のＤ７０気孔径が０．８０〜０．９０Ｚであり、前記モード気孔径の狭小率ＮＲ M に対する前記Ｄ３０気孔径の狭小率ＮＲ D30 の比率（ＮＲ D30 ／ＮＲ M ）が、０．８７〜０．９５である前記排ガス浄化触媒を得る、
排ガス浄化触媒の製造方法。 An exhaust gas purification catalyst manufacturing method for purifying exhaust gas discharged from a gasoline engine,
A wall flow type substrate in which an introduction side cell having an open end on the exhaust gas introduction side and a discharge side cell having an open end on the exhaust gas discharge side adjacent to the introduction side cell is defined by a porous partition wall. A preparation process;
A catalyst layer forming step of applying a catalyst slurry to at least a part of the pore surface in the partition wall of the wall flow type substrate to form a catalyst layer, and
In the catalyst layer forming step, in the pore size distribution, when the mode pore diameter of the partition wall of the wall flow type substrate is X, the mode pore diameter of the partition wall on which the catalyst layer is formed is 0.6X or more and 0 .9X or less, and in the pore size distribution where the minimum pore size is 1 μm, when the D30 pore size of the partition wall of the wall flow type substrate is Y, the D30 pore size of the partition wall on which the catalyst layer is formed Is 0.69 to 0.80Y, and when the D70 pore diameter of the partition wall of the wall flow type substrate is Z, the D70 pore diameter of the partition wall on which the catalyst layer is formed is 0.80 to 0.8. 90Z der is, the ratio of the mode pore diameter narrowing rate NR narrowing ratio of the D30 pore diameter to M NR D30 (NR D30 / NR M) is, the exhaust gas purifying catalyst Ru der from 0.87 to 0.95 obtain,
A method for producing an exhaust gas purification catalyst.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2018149978 | 2018-08-09 | ||
| JP2018149978 | 2018-08-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP6608090B1 true JP6608090B1 (en) | 2019-11-20 |
| JP2020025954A JP2020025954A (en) | 2020-02-20 |
Family
ID=68611046
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2019140093A Active JP6608090B1 (en) | 2018-08-09 | 2019-07-30 | Exhaust gas purification catalyst |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP6608090B1 (en) |
| CN (1) | CN112218719B (en) |
| WO (1) | WO2020031794A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2022111085A (en) * | 2021-01-19 | 2022-07-29 | 本田技研工業株式会社 | Exhaust gas purification filter |
| JPWO2022163720A1 (en) * | 2021-02-01 | 2022-08-04 |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004330118A (en) * | 2003-05-09 | 2004-11-25 | Tokyo Yogyo Co Ltd | Filter for clarifying exhaust gas |
| WO2008126331A1 (en) * | 2007-03-30 | 2008-10-23 | Ibiden Co., Ltd. | Honeycomb filter |
| JP4753209B2 (en) * | 2007-12-06 | 2011-08-24 | 本田技研工業株式会社 | Oxidation catalyst equipment for exhaust gas purification |
| EP2335823B8 (en) * | 2008-08-27 | 2015-11-18 | Umicore Shokubai Japan Co., Ltd. | Exhaust gas purification catalyst and exhaust gas purification method using same |
| GB0903262D0 (en) * | 2009-02-26 | 2009-04-08 | Johnson Matthey Plc | Filter |
| JP5964564B2 (en) * | 2011-09-05 | 2016-08-03 | 日本碍子株式会社 | Wall flow type exhaust gas purification filter |
| JP6594149B2 (en) * | 2015-10-05 | 2019-10-23 | 株式会社キャタラー | Exhaust gas purification device |
| JP6689641B2 (en) * | 2016-03-25 | 2020-04-28 | 日本碍子株式会社 | Honeycomb structure |
| JP6934311B2 (en) * | 2016-06-02 | 2021-09-15 | 株式会社キャタラー | Exhaust gas purification filter |
| CN106799225B (en) * | 2016-12-27 | 2019-06-11 | 中国科学院上海硅酸盐研究所 | A kind of potassium support type soot combustion catalyst and its preparation method and application |
| WO2019058948A1 (en) * | 2017-09-21 | 2019-03-28 | 株式会社キャタラー | Catalyst for exhaust gas purification |
| JP6567035B2 (en) * | 2017-12-28 | 2019-08-28 | 本田技研工業株式会社 | Exhaust purification filter |
-
2019
- 2019-07-30 WO PCT/JP2019/029874 patent/WO2020031794A1/en active Application Filing
- 2019-07-30 JP JP2019140093A patent/JP6608090B1/en active Active
- 2019-07-30 CN CN201980036868.8A patent/CN112218719B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| WO2020031794A1 (en) | 2020-02-13 |
| CN112218719B (en) | 2021-09-14 |
| CN112218719A (en) | 2021-01-12 |
| JP2020025954A (en) | 2020-02-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10183253B2 (en) | Exhaust gas purification device | |
| JPWO2016060049A1 (en) | Exhaust gas purification catalyst | |
| WO2020031975A1 (en) | Catalyst-coated gasoline particulate filter and method for producing same | |
| JP6608090B1 (en) | Exhaust gas purification catalyst | |
| JP7051186B2 (en) | Exhaust gas purification catalyst | |
| JP6526847B1 (en) | Exhaust gas purification catalyst and method for producing the same | |
| JP6523496B1 (en) | Exhaust gas purification catalyst and method for producing the same | |
| JP6617181B1 (en) | Exhaust gas purification catalyst | |
| WO2019221214A1 (en) | Exhaust gas purifying catalyst | |
| WO2019221216A1 (en) | Method for manufacturing exhaust gas purification catalyst | |
| WO2019221212A1 (en) | Exhaust gas purification catalyst and method for producing same | |
| JP6581262B1 (en) | Method for producing exhaust gas purification catalyst | |
| JP7319293B2 (en) | Exhaust gas purification catalyst and its manufacturing method | |
| JP7075282B2 (en) | Exhaust gas purification catalyst | |
| WO2019221217A1 (en) | Exhaust gas purification catalyst | |
| WO2022163720A1 (en) | Exhaust gas purification catalyst filter for gasoline engine | |
| WO2021059883A1 (en) | Exhaust-gas-purifying catalyst production method | |
| JP6526846B1 (en) | Exhaust gas purification catalyst and method for producing the same | |
| JP2023072745A (en) | Catalyst for exhaust gas purification, and method for producing the same | |
| JP2022156448A (en) | Exhaust gas purification catalyst for gasoline engine and exhaust gas purification system using the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20190807 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20190807 |
|
| A871 | Explanation of circumstances concerning accelerated examination |
Free format text: JAPANESE INTERMEDIATE CODE: A871 Effective date: 20190807 |
|
| A975 | Report on accelerated examination |
Free format text: JAPANESE INTERMEDIATE CODE: A971005 Effective date: 20190819 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20190829 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20190925 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20191010 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20191021 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 6608090 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |