JP2003245551A - ABSORPTION AND REDUCTION CATALYST FOR REMOVING NOx - Google Patents
ABSORPTION AND REDUCTION CATALYST FOR REMOVING NOxInfo
- Publication number
- JP2003245551A JP2003245551A JP2002045124A JP2002045124A JP2003245551A JP 2003245551 A JP2003245551 A JP 2003245551A JP 2002045124 A JP2002045124 A JP 2002045124A JP 2002045124 A JP2002045124 A JP 2002045124A JP 2003245551 A JP2003245551 A JP 2003245551A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- purification
- storage
- absorption
- solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 98
- 238000010521 absorption reaction Methods 0.000 title abstract 7
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 15
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 10
- 150000001875 compounds Chemical class 0.000 claims abstract description 8
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 6
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 5
- 229910052788 barium Inorganic materials 0.000 claims abstract description 4
- 229910052751 metal Inorganic materials 0.000 claims abstract description 3
- 239000002184 metal Substances 0.000 claims abstract description 3
- 238000000746 purification Methods 0.000 claims description 42
- 239000011232 storage material Substances 0.000 claims description 18
- 238000004519 manufacturing process Methods 0.000 claims 1
- 238000001179 sorption measurement Methods 0.000 claims 1
- 238000005245 sintering Methods 0.000 abstract description 11
- 238000001354 calcination Methods 0.000 abstract description 2
- 238000004140 cleaning Methods 0.000 abstract 1
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 42
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 37
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 19
- 239000000843 powder Substances 0.000 description 13
- 239000002245 particle Substances 0.000 description 12
- 239000007789 gas Substances 0.000 description 10
- 239000000758 substrate Substances 0.000 description 9
- 239000000243 solution Substances 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 6
- 239000002002 slurry Substances 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 5
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical group [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 5
- 238000010304 firing Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 3
- 229910052783 alkali metal Inorganic materials 0.000 description 3
- 150000001340 alkali metals Chemical class 0.000 description 3
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 3
- 150000001342 alkaline earth metals Chemical class 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- IXSUHTFXKKBBJP-UHFFFAOYSA-L azanide;platinum(2+);dinitrite Chemical compound [NH2-].[NH2-].[Pt+2].[O-]N=O.[O-]N=O IXSUHTFXKKBBJP-UHFFFAOYSA-L 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000009616 inductively coupled plasma Methods 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 2
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 102100033041 Carbonic anhydrase 13 Human genes 0.000 description 1
- 101100321669 Fagopyrum esculentum FA02 gene Proteins 0.000 description 1
- 101000867860 Homo sapiens Carbonic anhydrase 13 Proteins 0.000 description 1
- 101000741917 Homo sapiens Serine/threonine-protein phosphatase 1 regulatory subunit 10 Proteins 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910002666 PdCl2 Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 102100038743 Serine/threonine-protein phosphatase 1 regulatory subunit 10 Human genes 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- ITHZDDVSAWDQPZ-UHFFFAOYSA-L barium acetate Chemical compound [Ba+2].CC([O-])=O.CC([O-])=O ITHZDDVSAWDQPZ-UHFFFAOYSA-L 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 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 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000004993 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
- 239000000446 fuel Substances 0.000 description 1
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 150000002941 palladium compounds Chemical class 0.000 description 1
- CLSUSRZJUQMOHH-UHFFFAOYSA-L platinum dichloride Chemical compound Cl[Pt]Cl CLSUSRZJUQMOHH-UHFFFAOYSA-L 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 235000011056 potassium acetate Nutrition 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 150000003256 radium compounds Chemical class 0.000 description 1
- 229910052701 rubidium Inorganic materials 0.000 description 1
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/19—Catalysts containing parts with different compositions
-
- 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
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9413—Processes characterised by a specific catalyst
- B01D53/9422—Processes characterised by a specific catalyst for removing nitrogen oxides by NOx storage or reduction by cyclic switching between lean and rich exhaust gases (LNT, NSC, NSR)
-
- 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
- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
- B01J23/44—Palladium
-
- 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
- B01J23/58—Platinum group metals with alkali- or alkaline earth metals
-
- 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
- B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
- B01J35/396—Distribution of the active metal ingredient
-
- 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
- B01J37/024—Multiple impregnation or coating
-
- 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
- B01J37/04—Mixing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/10—Noble metals or compounds thereof
- B01D2255/102—Platinum group metals
- B01D2255/1021—Platinum
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/10—Noble metals or compounds thereof
- B01D2255/102—Platinum group metals
- B01D2255/1023—Palladium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/202—Alkali metals
- B01D2255/2022—Potassium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/202—Alkali metals
- B01D2255/2025—Lithium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/204—Alkaline earth metals
- B01D2255/2042—Barium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/209—Other metals
- B01D2255/2092—Aluminium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/90—Physical characteristics of catalysts
- B01D2255/91—NOx-storage component incorporated in the catalyst
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Combustion & Propulsion (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、高温雰囲気下での
触媒成分のシンタリングが顕著に抑制され、高い耐久性
能を有する吸蔵還元型NOx浄化用触媒に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage-reduction type NO x purifying catalyst which has a high durability and in which sintering of catalyst components in a high temperature atmosphere is significantly suppressed.
【0002】[0002]
【従来の技術】地球環境保護のため、自動車用エンジン
等の内燃機関から排出される二酸化炭素(CO2)の発生
量を抑え、かつ窒素酸化物(NOx)の発生量を抑えるこ
とが世界的課題となっている。こうした課題に対し、燃
費の高いリーンバーンエンジンと、その排気ガスを浄化
する触媒としての吸蔵還元型NOx浄化用触媒が開発さ
れている。2. Description of the Related Art In order to protect the global environment, it is a world-wide practice to reduce the amount of carbon dioxide (CO 2 ) emitted from internal combustion engines such as automobile engines, and the amount of nitrogen oxides (NO x ). Has become a problem. To solve these problems, a lean burn engine with high fuel efficiency and a storage reduction type NO x purification catalyst as a catalyst for purifying exhaust gas thereof have been developed.
【0003】この吸蔵還元型NOx浄化用触媒は、一般
に、白金(Pt)、パラジウム(Pd)等の触媒成分に加
え、NOx吸蔵材としてアルカリ金属又はアルカリ土類
金属をγ-アルミナ等の担体に担持して構成される。N
Oxは、リーン条件下でアルカリ金属又はアルカリ土類
金属によって吸蔵され、その吸蔵したNOxを一時的な
ストイキ〜リッチ条件下で放出させ、白金等の触媒作用
と一時的な還元性雰囲気によって、その放出させたNO
xを還元浄化する。This storage reduction type NO x purification catalyst generally contains a catalyst component such as platinum (Pt) or palladium (Pd), and an alkali metal or alkaline earth metal such as γ-alumina as a NO x storage material. It is configured to be carried on a carrier. N
O x is occluded by an alkali metal or alkaline earth metal under lean conditions, to release the occluded NO x in temporary stoichiometric-rich conditions, the catalytic activity and the temporary reducing atmosphere, such as platinum , The released NO
Reduce and purify x .
【0004】しかるに、こうした触媒が、排気ガスの浄
化反応を効率的に促進するためには、触媒成分が排気ガ
スと大きい面積で接触するように、担体上に触媒成分が
高分散に担持され、そして、この高分散の担持状態が、
排気ガス雰囲気下で経時的に維持されることが必要であ
る。However, in order for such a catalyst to efficiently promote the purification reaction of exhaust gas, the catalyst component is supported on the carrier in a highly dispersed manner so that the catalyst component comes into contact with the exhaust gas in a large area. And, this highly dispersed loading state is
It needs to be maintained over time in an exhaust gas atmosphere.
【0005】ここで、自動車用エンジンの排気ガスは、
常温と高くは約1000℃の間で温度の変化を繰り返
し、かつ比較的HCとCOの濃度が高くてO2濃度が低
い還元性雰囲気と、比較的HCとCOの濃度が低くてO
2濃度が高い酸化性雰囲気を繰り返す。Here, the exhaust gas of an automobile engine is
A temperature change is repeated between room temperature and high at about 1000 ° C., and a reducing atmosphere having a relatively high concentration of HC and CO and a low O 2 concentration and an oxygen having a relatively low concentration of HC and CO
2 Repeat the oxidizing atmosphere with high concentration.
【0006】[0006]
【発明が解決しようとする課題】しかしながら、白金等
の貴金属の触媒成分には、こうした雰囲気に長期間曝さ
れると、特に高温の酸化性雰囲気において、触媒成分が
移動して肥大化した粒子を形成する、いわゆるシンタリ
ングを生じる性質がある。このため、触媒成分は、排気
ガスとの高い接触面積を維持することができず、排気ガ
スの浄化性能が経時的に低下するという問題がある。However, when a catalyst component of a noble metal such as platinum is exposed to such an atmosphere for a long period of time, the catalyst component migrates and enlarges particles, especially in a high temperature oxidizing atmosphere. It has the property of forming, so-called sintering. For this reason, the catalyst component cannot maintain a high contact area with the exhaust gas, and there is a problem that the exhaust gas purification performance deteriorates with time.
【0007】ところで、本出願人等は、特開平11−3
00203号公報、特開平7−251073号公報等に
おいて、PtとPdを含み、シンタリングが抑制された
排気ガス浄化用触媒を提案している。本発明は、このよ
うな先行技術とは異なる触媒構成により、触媒成分のシ
ンタリングが抑制され、広い温度範囲で経時的に安定し
て高いNOx浄化性能を発揮する吸蔵還元型NOx浄化用
触媒を提供することを目的とする。By the way, the applicant of the present invention has disclosed in Japanese Patent Laid-Open No. 11-3
In Japanese Patent Laid-Open No. 00203, Japanese Unexamined Patent Publication No. 7-251073, etc., an exhaust gas purifying catalyst containing Pt and Pd and suppressing sintering is proposed. The present invention, by catalytic structure which is different from such prior art, sintering of the catalyst component is suppressed, for storage reduction the NO x purification to exhibit stable over time with higher the NO x purification performance over a wide temperature range The purpose is to provide a catalyst.
【0008】[0008]
【課題を解決するための手段】上記の目的は、酸化物担
体上にPt、Pd、及びNOx吸蔵材が担持された第1
触媒、並びに、酸化物担体上にPd、及びNOx吸蔵材
が担持された第2触媒を含んでなる吸蔵還元型NOx浄
化用触媒によって達成される。即ち、本発明の触媒は、
第1触媒と第2触媒を含んでなる吸蔵還元型NOx浄化
用触媒であって、Ptが第1触媒のみに担持され、Pd
が第1触媒と第2触媒の双方に担されることにより、P
tのシンタリングが抑制され、経時的に安定して高いN
Ox浄化性能を発揮する触媒である。SUMMARY OF THE INVENTION The above object is to provide a first oxide carrier having Pt, Pd, and a NO x storage material supported thereon.
This is achieved by a catalyst and a storage reduction type NO x purification catalyst including a second catalyst in which Pd and a NO x storage material are supported on an oxide carrier. That is, the catalyst of the present invention is
A storage reduction type NO x purification catalyst including a first catalyst and a second catalyst, wherein Pt is supported only on the first catalyst, and Pd
Is carried by both the first catalyst and the second catalyst,
Sintering of t is suppressed and the N value is stable and high over time.
It is a catalyst that exhibits O x purification performance.
【0009】図1は、かかる触媒のモデル図であり、酸
化物担体上でPt粒子を取り囲んでPdが存在し、それ
らの周りにNOx吸蔵材が存在する状態の第1触媒と、
酸化物担体にPdが存在し、その周りにNOx吸蔵材が
存在する状態の第2触媒が、混在して共存する状態を示
す。こうした触媒においてシンタリングが抑制され、広
い温度範囲で経時的に安定して高いNOx浄化性能を発
揮することができる理由は、次のように考えられる。FIG. 1 is a model diagram of such a catalyst, in which Pd particles are present on an oxide carrier to surround Pt particles, and a NO x storage material is present around them, and a first catalyst,
The second catalyst, in which Pd is present in the oxide carrier and the NO x storage material is present around it, is present in a mixed state. The reason why sintering is suppressed in such a catalyst and a high NO x purification performance can be stably exerted over a wide temperature range over time is considered as follows.
【0010】第1触媒に関し、Ptは、高温酸化性雰囲
気において比較的シンタリングを生じやすい性質を有す
るが、Pdは、比較的シンタリングを生じにくいという
性質を有する。したがって、Pt粒子の周囲にPdが存
在することで、Pt移動の抑制作用が生じることができ
る。Regarding the first catalyst, Pt has a property that sintering is relatively likely to occur in a high temperature oxidizing atmosphere, while Pd has a property that sintering is relatively unlikely to occur. Therefore, the presence of Pd around the Pt particles can have an effect of suppressing Pt movement.
【0011】そして、とりわけ、Pd/(Pt+Pd)の
モル比が0.02〜0.2であるときにかかる状態が発現
することができ、また、Pt化合物とPd化合物を溶解
させた溶液を酸化物担体に含浸させ、次いで焼成するこ
とにより、かかる状態が、微細な形態で発現することが
でき、それによって、触媒成分の担体上での高分散性
と、この高分散の安定性が得られるものと考えられる。Especially, when the molar ratio of Pd / (Pt + Pd) is 0.02 to 0.2, such a state can be exhibited, and the solution in which the Pt compound and the Pd compound are dissolved is oxidized. Such a state can be expressed in a finely-divided form by impregnating the material carrier with the material and then calcining, whereby high dispersibility of the catalyst component on the carrier and stability of this high dispersion can be obtained. It is considered to be a thing.
【0012】一方、上記のリーン条件と一時的なストイ
キ〜リッチ条件の繰り返しによるNOxの浄化におい
て、Ptは比較的高い温度でNOx浄化作用を奏する
が、Pt粒子は殆どが表出しているため、このNOx浄
化作用は維持される。したがって、第1触媒は、主とし
て、比較的高い温度で高いNOx浄化作用を提供するこ
とができる。On the other hand, in the purification of NO x by repeating the lean condition and the temporary stoichiometric-rich condition, Pt exerts a NO x purification action at a relatively high temperature, but most Pt particles are exposed. Therefore, this NO x purification action is maintained. Therefore, the first catalyst can mainly provide a high NO x purification action at a relatively high temperature.
【0013】次に、第2触媒に関し、Pdは、比較的シ
ンタリングを生じにくいという性質を有する一方で、比
較的高い温度では、酸素貯蔵能のためにそれ程NOx浄
化作用を奏しないが、比較的低い温度では高いNOx浄
化作用を奏する。したがって、第2触媒は、主として、
比較的低い温度で高いNOx浄化作用を提供することが
できる。Next, regarding the second catalyst, while Pd has a property that sintering is relatively unlikely to occur, at a relatively high temperature, it does not exert so much NO x purification action due to its oxygen storage capacity. A high NO x purification action is exhibited at a relatively low temperature. Therefore, the second catalyst is mainly
It is possible to provide a high NO x purification action at a relatively low temperature.
【0014】このため、第1触媒と第2触媒が共存する
ことで、広範囲な温度にわたって高いNOx浄化性能を
発揮する触媒を提供することができ、とりわけ、第1触
媒に含まれる(Pt+Pd)のモル量に対する第2触媒に
含まれるPdのモル量が、Pd/(Pt+Pd)のモル比
として0.9〜1.0であるときに、このNOx浄化性能
が最適化されるものと考えられる。Therefore, the coexistence of the first catalyst and the second catalyst makes it possible to provide a catalyst exhibiting a high NO x purification performance over a wide temperature range, and in particular (Pt + Pd) contained in the first catalyst. It is considered that the NO x purification performance is optimized when the molar amount of Pd contained in the second catalyst with respect to the molar amount of Pd / (Pt + Pd) is 0.9 to 1.0. To be
【0015】[0015]
【発明の実施の形態】本発明の吸蔵還元型NOx浄化用
触媒は、酸化物担体上にPt、Pd、及びNOx吸蔵材
が担持された第1触媒、並びに、酸化物担体上にPd、
及びNOx吸蔵材が担持された第2触媒を含んで構成さ
れる。BEST MODE FOR CARRYING OUT THE INVENTION The storage reduction type NO x purification catalyst of the present invention comprises a first catalyst in which Pt, Pd, and a NO x storage material are supported on an oxide carrier, and Pd on the oxide carrier. ,
And a second catalyst carrying an NO x storage material.
【0016】これら第1触媒と第2触媒の酸化物担体
は、アルミナ、シリカ、ジルコニアのような酸化物のほ
か、シリカ-アルミナ、ジルコニア-セリア、アルミナ-
セリア-ジルコニア、セリア-ジルコニア-イットリア、
ジルコニア-カルシアのような複合酸化物からなるもの
で、平均粒子径が1μm以下の微粒子からなるものが好
適に使用可能であり、第1触媒と第2触媒の酸化物担体
は、同じ種類の酸化物又は異なる種類の酸化物からなる
ことができる。The oxide carriers of the first catalyst and the second catalyst are oxides such as alumina, silica and zirconia, as well as silica-alumina, zirconia-ceria and alumina-.
Ceria-zirconia, ceria-zirconia-yttria,
A composite oxide such as zirconia-calcia, which is composed of fine particles having an average particle size of 1 μm or less, can be preferably used, and the oxide supports of the first catalyst and the second catalyst are the same kind of oxidation. It can consist of a material or a different kind of oxide.
【0017】第1触媒の調製に関し、このような酸化物
担体にPtとPdを担持するのは、好ましくは、ジニト
ロジアンミン白金錯体Pt(NH3)2(NO2)2、塩化白金
酸H 2PtCl6・6H2O等の白金化合物と、硝酸パラ
ジウムPd(NO3)2、塩化パラジウムPdCl2等のパ
ラジウム化合物を用い、これらの化合物を、所定のPd
/(Pt+Pd)のモル比となる量で溶解させた溶液を調
製し、この溶液を上記の酸化物担体に含浸し、次いで乾
燥・焼成することによって行う。焼成は、例えば、大気
雰囲気の450〜650℃の温度で数時間加熱すること
によって行うことができる。With regard to the preparation of the first catalyst, such oxides
Supporting Pt and Pd on the carrier is preferably zinito
Rodiammine platinum complex Pt (NH3)2(NO2)2, Platinum chloride
Acid H 2PtCl6・ 6H2Platinum compounds such as O and para nitrate
Dium Pd (NO3)2, Palladium chloride PdCl2Etc.
Radium compounds are used, and these compounds
Prepare a solution that has been dissolved in an amount that results in a molar ratio of / (Pt + Pd).
And impregnate this solution into the above oxide support, then dry.
It is done by drying and baking. Firing is performed in the atmosphere, for example.
Heating at ambient temperature of 450-650 ° C for several hours
Can be done by
【0018】酸化物担体に担持されるNOx吸蔵材とし
ては、リチウム(Li)、ナトリウム(Na)、カリウム
(K)、ルビジウム(Rb)のアルカリ金属、及びマグネシ
ウム(Mg)、カルシウム(Ca)、ストロンチウム(S
r)、バリウム(Ba)のアルカリ土類金属の少なくとも
1種が例示され、好ましくは、Li、K、及びBaから
選択された少なくとも1種の金属を含む。The NO x storage material supported on the oxide carrier includes lithium (Li), sodium (Na) and potassium.
(K), alkali metal of rubidium (Rb), and magnesium (Mg), calcium (Ca), strontium (S
r) and at least one kind of alkaline earth metal of barium (Ba) are exemplified, and preferably, at least one kind of metal selected from Li, K, and Ba is included.
【0019】好ましくは、NOx吸蔵材は、PtとPd
を担持した後に担持する。この担持の仕方としては、こ
れらNOx吸蔵材の溶液を調製し、この溶液を上記の酸
化物担体に含浸し、次いで乾燥・焼成することによって
行うことができる。Preferably, the NO x storage material is Pt and Pd.
Is carried and then carried. As a method of carrying this, it is possible to prepare a solution of these NO x storage materials, impregnate this solution into the above oxide carrier, and then dry and calcine.
【0020】第2触媒は、第1触媒と同様に、好ましく
は、硝酸パラジウムPd(NO3)2、塩化パラジウムPd
Cl2等のパラジウム化合物を用い、これらの化合物
を、所定の量で溶解させた溶液を調製し、この溶液を上
記の酸化物担体に含浸し、次いで乾燥・焼成することに
よってPdを担持し、さらに、好ましくは、Li、K、
及びBaから選択された少なくとも1種のNOx吸蔵材
を担持して調製することができる。Like the first catalyst, the second catalyst is preferably palladium nitrate Pd (NO 3 ) 2 or palladium chloride Pd.
A palladium compound such as Cl 2 is used to prepare a solution in which these compounds are dissolved in a predetermined amount, and the above oxide carrier is impregnated with this solution, and then dried and calcined to support Pd, Further, preferably Li, K,
And at least one NOx storage material selected from Ba.
【0021】このようにして調製された第1触媒と第2
触媒は、例えば、水を媒体にしてボールミル等で湿式混
合した後、乾燥して、あるいは、粉末状の第1触媒と第
2触媒をヘンシェルミキサー等で乾式混合して、本発明
の吸蔵還元型NOx浄化用触媒を得ることができる。The first catalyst and the second catalyst thus prepared
The catalyst is, for example, wet-mixed with a ball mill or the like using water as a medium and then dried, or the powdery first catalyst and the second catalyst are dry-mixed with a Henschel mixer or the like, and the storage reduction type of the present invention is used. A NO x purification catalyst can be obtained.
【0022】また、本発明の吸蔵還元型NOx浄化用触
媒が、通常のハニカム基材にコートされる場合、第1触
媒と第2触媒のNOx吸蔵材の担持は、NOx吸蔵材が担
持される前の、PtとPdが担持された第1触媒と第2
触媒をハニカム基材にコートした後、そのハニカム基材
上のコート層にNOx吸蔵材の溶液を含浸し、次いで乾
燥・焼成することによって同時に行うこともできる。以
下、実施例によって本発明をより具体的に説明する。Further, storage reduction the NO x purification catalyst of the present invention, when coated on conventional honeycomb substrate, carrying of the NO x storage material of the first catalyst and the second catalyst, the NO x storage material Before being loaded, Pt and Pd loaded first catalyst and second
After the catalyst is coated on the honeycomb base material, the coating layer on the honeycomb base material is impregnated with the solution of the NO x storage material, and then dried and fired. Hereinafter, the present invention will be described more specifically with reference to Examples.
【0023】[0023]
【実施例】実施例1
γ-アルミナ粉末(比表面積約180m2/g)に、ジニト
ロジアンミン白金錯体と硝酸パラジウムを溶解した水溶
液(Pt濃度4.61質量%、Pd濃度4.33質量%)を
用いて、γ-アルミナ粉末120gあたり5.75gのP
tと0.15gのPdとなるように含浸し、乾燥の後、
300℃の大気雰囲気中で1時間焼成した。別に、γ-
アルミナ粉末に、硝酸パラジウムの水溶液(Pd濃度4.
33質量%)を用いて、γ-アルミナ粉末120gあたり
3.25gのPdとなるように含浸し、乾燥の後、40
0℃の大気雰囲気中で1時間焼成した。Example 1 An aqueous solution in which a dinitrodiammine platinum complex and palladium nitrate were dissolved in γ-alumina powder (specific surface area: about 180 m 2 / g) (Pt concentration 4.61% by mass, Pd concentration 4.33% by mass). 5.75 g of P per 120 g of γ-alumina powder
t and 0.15 g of Pd, and after drying,
Firing was performed for 1 hour in an air atmosphere at 300 ° C. Separately, γ-
An aqueous solution of palladium nitrate (Pd concentration 4.
33% by mass) to impregnate 120 g of γ-alumina powder with 3.25 g of Pd, and after drying, 40
Firing was performed for 1 hour in an atmosphere of 0 ° C.
【0024】これらのPtPd/γ-アルミナ粉末とP
d/γ-アルミナ粉末を1:1の質量比で混合し、さら
に100gのアルミナゾル(日産化学製A-200)と2
00ccのイオン交換水を加えてボールミル中で2時間
混合し、スラリーを作成した。得られたスラリーを、直
径30mm×長さ50mmのコージェライト製ハニカム
基材にウォッシュコートし、120℃で2時間乾燥した
後、500℃の大気雰囲気中で1時間焼成して、ハニカ
ム基材1リットルあたり5.75gのPtと3.4gのP
dを担持した。These PtPd / γ-alumina powder and P
d / γ-alumina powder was mixed in a mass ratio of 1: 1 and further mixed with 100 g of alumina sol (Nissan Chemical A-200) and 2
Ion-exchanged water (00 cc) was added and mixed in a ball mill for 2 hours to prepare a slurry. The obtained slurry is wash-coated on a cordierite honeycomb substrate having a diameter of 30 mm and a length of 50 mm, dried at 120 ° C. for 2 hours, and then fired at 500 ° C. for 1 hour in an air atmosphere to obtain a honeycomb substrate 1. 5.75 g Pt and 3.4 g P per liter
carried d.
【0025】次いでこのコート層に、酢酸バリウム、酢
酸カリウム、及び酢酸リチウムを溶解した水溶液を吸水
させ、乾燥の後、500℃の大気雰囲気中で1時間焼成
して、ハニカム基材1リットルあたり0.2モルのB
a、0.1モルのK、0.1モルのLiを担持し、本発明
の触媒を調製した。Next, the coating layer is made to absorb an aqueous solution in which barium acetate, potassium acetate and lithium acetate are dissolved, dried and then baked in an air atmosphere at 500 ° C. for 1 hour to give 0 per 1 liter of honeycomb substrate. .2 mol B
The catalyst of the present invention was prepared by carrying a, 0.1 mol of K, and 0.1 mol of Li.
【0026】比較例1
γ-アルミナ粉末に、ジニトロジアンミン白金錯体と硝
酸パラジウムを溶解した水溶液(Pt濃度4.61質量
%、Pd濃度4.33質量%)を用いて、γ-アルミナ粉
末120gあたり5.75gのPtと0.15gのPdと
なるように含浸し、乾燥の後、400℃の大気雰囲気中
で1時間焼成した。Comparative Example 1 An aqueous solution (Pt concentration 4.61% by mass, Pd concentration 4.33% by mass) in which dinitrodiammine platinum complex and palladium nitrate were dissolved in γ-alumina powder was used per 120 g of γ-alumina powder. It was impregnated with 5.75 g of Pt and 0.15 g of Pd, dried, and then baked in an air atmosphere at 400 ° C. for 1 hour.
【0027】このPtPd/γ-アルミナ粉末に100
gのアルミナゾルと200ccのイオン交換水を加えて
ボールミル中で2時間混合し、スラリーを作成した。次
いで、実施例1と同様にして、得られたスラリーをハニ
カム基材にウォッシュコートした後、さらに、実施例1
と同様にして、ハニカム基材1リットルあたり0.2モ
ルのBa、0.1モルのK、0.1モルのLiを担持し、
比較例の触媒を調製した。100 parts of this PtPd / γ-alumina powder
g of alumina sol and 200 cc of ion-exchanged water were added and mixed in a ball mill for 2 hours to prepare a slurry. Then, the honeycomb substrate was wash-coated with the obtained slurry in the same manner as in Example 1, and then, further in Example 1.
In the same manner as above, 0.2 mol of Ba, 0.1 mol of K, and 0.1 mol of Li are carried per liter of the honeycomb substrate,
A comparative catalyst was prepared.
【0028】比較例2
γ-アルミナ粉末に、硝酸パラジウムを溶解した水溶液
(Pd濃度4.33質量%)を用いて、γ-アルミナ粉末1
20gあたり3.25gのPdとなるように含浸し、乾
燥の後、400℃の大気雰囲気中で1時間焼成した。Comparative Example 2 Aqueous solution in which palladium nitrate was dissolved in γ-alumina powder
Γ-alumina powder 1 using (Pd concentration 4.33% by mass)
It was impregnated with Pd of 3.25 g per 20 g, dried, and then calcined for 1 hour in an air atmosphere at 400 ° C.
【0029】このPd/γ-アルミナ粉末に100gの
アルミナゾルと200ccのイオン交換水を加えてボー
ルミル中で2時間混合し、スラリーを作成した。次い
で、実施例1と同様にして、得られたスラリーをハニカ
ム基材にウォッシュコートし、乾燥・焼成した後、実施
例1と同様にして、ハニカム基材1リットルあたり0.
2モルのBa、0.1モルのK、0.1モルのLiを担持
し、比較例の触媒を調製した。To this Pd / γ-alumina powder, 100 g of alumina sol and 200 cc of ion-exchanged water were added and mixed in a ball mill for 2 hours to prepare a slurry. Then, in the same manner as in Example 1, the resulting slurry was wash-coated on the honeycomb substrate, dried and fired, and then, in the same manner as in Example 1, per 1 liter of the honeycomb substrate.
A catalyst of Comparative Example was prepared by supporting 2 mol of Ba, 0.1 mol of K and 0.1 mol of Li.
【0030】−NOx浄化性能の評価−
上記の得られた各触媒を大気雰囲気中の850℃×2時
間の熱処理に供した後、下記のモデルガスで300℃、
400℃、及び500℃におけるNOx浄化率を測定し
た。この結果を図2にまとめて示す。
モデルガス組成:
500ppmNO+2000ppmHC+0.6%CO
+10%CO2+0.3%O2+5%H2O(残余:N2)-Evaluation of NO x purification performance- Each of the above-obtained catalysts was subjected to heat treatment in an air atmosphere at 850 ° C for 2 hours, and then the following model gas was used at 300 ° C.
The NO x purification rate at 400 ° C. and 500 ° C. was measured. The results are summarized in FIG. Model gas composition: 500ppm NO + 2000ppm HC + 0.6% CO
+ 10% CO 2 + 0.3% O 2 + 5% H 2 O (remainder: N 2 )
【0031】−触媒成分の粒子径−
ハニカム基材を用いない以外は実施例1と同様にして、
γ-アルミナ粉末に、表1に示す量の触媒成分のPtと
Pd、及びNOx吸蔵材のBa、K、Liを担持し、そ
れぞれのγ-アルミナ粉末を、大気雰囲気中で750℃
×5時間の焼成に供した後、誘導結合プラズマ発光分析
(ICP)によるPtとPdの組成分析、及び粉末X線回
折(XRD)による触媒成分の粒子径の測定を行った。こ
の結果を図3にまとめて示す。なお、図3に示した粒子
径は、触媒成分がPtのみの粒子径を基準にした相対値
で示す。-Particle size of catalyst component-The same as in Example 1 except that the honeycomb substrate was not used,
The amounts of catalyst components Pt and Pd shown in Table 1 and the NO x storage materials Ba, K, and Li were carried on the γ-alumina powder, and the respective γ-alumina powders were heated at 750 ° C. in the atmosphere.
Inductively coupled plasma emission spectrometry after firing for 5 hours
The composition of Pt and Pd was analyzed by (ICP), and the particle size of the catalyst component was measured by powder X-ray diffraction (XRD). The results are summarized in FIG. The particle diameter shown in FIG. 3 is shown as a relative value based on the particle diameter of Pt alone as the catalyst component.
【0032】−結果より−
図2に示したNOx浄化率から、比較例1は、低温側の
NOx浄化率は比較的低いが、高温側のNOx浄化率は比
較的高く、比較例2は、低温側のNOx浄化率は比較的
高いが、高温側のNOx浄化率は比較的低いといった結
果であるのに対し、実施例1は、全温度範囲で高いNO
x浄化率を示している。このことは、第1触媒と第2触
媒を含むことによって、双方のNOx浄化性能の総和と
して本発明の触媒のNOx浄化性能が発現し、それによ
って、全温度範囲で高いNOx浄化率が得られることを
示すものと理解される。[0032] - Results from - from the NO x purification rate shown in FIG. 2, Comparative Example 1, but the NO x purification rate of the low temperature side is relatively low, the NO x purification rate of the high temperature side is relatively high, Comparative Example The result of No. 2 is that the NO x purification rate on the low temperature side is relatively high, but the NO x purification rate on the high temperature side is relatively low, whereas in Example 1, the NO x purification rate is high over the entire temperature range.
x Indicates the purification rate. This can be achieved by including a first catalyst and a second catalyst, the NO x purification performance of the catalyst is expressed in the present invention as the sum of both of the NO x purifying performance, thereby high the NO x purification rate over temperature Is understood to indicate that
【0033】また、図3に示した結果から、第1触媒の
Pd/(Pt+Pd)のモル比に、触媒成分の粒子径の成
長が抑えられる特定の範囲が存在することが分かる。し
たがって、その範囲であれば第1触媒のNOx浄化性能
がより効果的に維持されるものと考えられる。Further, from the results shown in FIG. 3, it can be seen that the molar ratio Pd / (Pt + Pd) of the first catalyst has a specific range in which the growth of the particle diameter of the catalyst component is suppressed. Therefore, it is considered that the NO x purification performance of the first catalyst is more effectively maintained within this range.
【0034】[0034]
【発明の効果】触媒成分のシンタリングが抑制され、広
い温度範囲で経時的に安定して高いNOx浄化性能を発
揮する吸蔵還元型NOx浄化用触媒を提供することがで
きる。EFFECTS OF THE INVENTION It is possible to provide a storage reduction type NO x purification catalyst that suppresses sintering of catalyst components and stably exhibits high NO x purification performance over a wide temperature range.
【0035】[0035]
【表1】 [Table 1]
【図1】本発明の触媒の想定される形態を示すモデル図
である。FIG. 1 is a model diagram showing a possible form of a catalyst of the present invention.
【図2】NOx浄化率を比較したグラフである。FIG. 2 is a graph comparing NO x purification rates.
【図3】熱処理後の触媒成分の粒子径を示すグラフであ
る。FIG. 3 is a graph showing particle diameters of catalyst components after heat treatment.
フロントページの続き Fターム(参考) 4D048 AA06 AB02 BA10X BA14X BA15X BA30X BA31X BA41X BB02 EA04 4G069 AA03 AA08 BA01A BA01B BA13A BA13B BB02A BB02B BB04A BC03A BC03B BC04A BC04B BC13A BC13B BC72A BC72B BC75A BC75B CA02 CA03 CA08 CA13 EA19 FA02 FB19 FC08 Continued front page F-term (reference) 4D048 AA06 AB02 BA10X BA14X BA15X BA30X BA31X BA41X BB02 EA04 4G069 AA03 AA08 BA01A BA01B BA13A BA13B BB02A BB02B BB04A BC03A BC03B BC04A BC04B BC13A BC13B BC72A BC72B BC75A BC75B CA02 CA03 CA08 CA13 EA19 FA02 FB19 FC08
Claims (5)
吸蔵材が担持された第1触媒、並びに、酸化物担体上に
Pd、及びNOx吸蔵材が担持された第2触媒を含んで
なることを特徴とする吸蔵還元型NOx浄化用触媒。1. Pt, Pd, and NO x on an oxide support.
A storage-reduction type NO x purification catalyst comprising a first catalyst supporting an storage material and a second catalyst supporting Pd and an NO x storage material on an oxide carrier.
モル比が0.02〜0.2である請求項1に記載の吸蔵還
元型NOx浄化用触媒。2. The storage reduction type NO x purification catalyst according to claim 1, wherein the molar ratio of Pd / (Pt + Pd) in the first catalyst is 0.02 to 0.2.
量に対する第2触媒に含まれるPdのモル量が、Pd/
(Pt+Pd)のモル比として0.9〜1.0である請求項
1又は2に記載の吸蔵還元型NOx浄化用触媒。3. The molar amount of Pd contained in the second catalyst relative to the molar amount of (Pt + Pd) contained in the first catalyst is Pd /
The storage reduction type NO x purification catalyst according to claim 1 or 2, wherein the molar ratio of (Pt + Pd) is 0.9 to 1.0.
ら選択された少なくとも1種の金属を含む請求項1〜3
のいずれか1項に記載の吸蔵還元型NOx浄化用触媒。4. The NO x storage material contains at least one metal selected from Li, K, and Ba.
The storage reduction-type NO x purification catalyst according to any one of 1.
液を酸化物担体に含浸させた後焼成し、次いで、NOx
吸蔵材を担持することを特徴とする請求項1〜4のいず
れか1項に記載の吸蔵還元型NOx浄化用触媒に含まれ
る第1触媒の製造方法。5. An oxide carrier is impregnated with a solution in which a Pt compound and a Pd compound are dissolved, and then baked, and then NO x.
A method for producing a first catalyst included in the storage reduction type NO x purification catalyst according to any one of claims 1 to 4, wherein an adsorption material is carried.
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KR100629208B1 (en) | 2004-03-03 | 2006-09-27 | 미츠비시 후소 트럭 앤드 버스 코포레이션 | Exhaust purifier |
WO2014171443A1 (en) * | 2013-04-19 | 2014-10-23 | 株式会社キャタラー | Exhaust-gas purification catalyst |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
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KR100629208B1 (en) | 2004-03-03 | 2006-09-27 | 미츠비시 후소 트럭 앤드 버스 코포레이션 | Exhaust purifier |
WO2014171443A1 (en) * | 2013-04-19 | 2014-10-23 | 株式会社キャタラー | Exhaust-gas purification catalyst |
JP2014210238A (en) * | 2013-04-19 | 2014-11-13 | 株式会社キャタラー | Exhaust-gas purification catalyst |
US9522385B2 (en) | 2013-04-19 | 2016-12-20 | Cataler Corporation | Exhaust gas purifying catalyst |
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