JPH11169713A - Catalyst for purification of exhaust gas - Google Patents
Catalyst for purification of exhaust gasInfo
- Publication number
- JPH11169713A JPH11169713A JP9342913A JP34291397A JPH11169713A JP H11169713 A JPH11169713 A JP H11169713A JP 9342913 A JP9342913 A JP 9342913A JP 34291397 A JP34291397 A JP 34291397A JP H11169713 A JPH11169713 A JP H11169713A
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- catalyst
- alkaline earth
- tungsten
- gas purifying
- 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.)
- Withdrawn
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 66
- 238000000746 purification Methods 0.000 title abstract description 10
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims abstract description 34
- 150000001342 alkaline earth metals Chemical class 0.000 claims abstract description 30
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 27
- 150000001340 alkali metals Chemical class 0.000 claims abstract description 27
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 27
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 23
- 239000010937 tungsten Substances 0.000 claims abstract description 22
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052751 metal Inorganic materials 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims abstract description 11
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000003513 alkali Substances 0.000 claims abstract description 10
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 9
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910052792 caesium Inorganic materials 0.000 claims abstract description 5
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000002131 composite material Substances 0.000 claims abstract description 5
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 5
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 5
- 239000011591 potassium Substances 0.000 claims abstract description 5
- 229910052712 strontium Inorganic materials 0.000 claims abstract description 5
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910052788 barium Inorganic materials 0.000 claims abstract description 4
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000002485 combustion reaction Methods 0.000 claims abstract description 4
- 239000002245 particle Substances 0.000 claims abstract description 4
- 239000000446 fuel Substances 0.000 claims description 5
- 239000011247 coating layer Substances 0.000 claims 1
- 239000000758 substrate Substances 0.000 claims 1
- 239000007789 gas Substances 0.000 abstract description 27
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 4
- 239000001301 oxygen Substances 0.000 abstract description 4
- 229910052760 oxygen Inorganic materials 0.000 abstract description 4
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 abstract 3
- 238000010521 absorption reaction Methods 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 239000002250 absorbent Substances 0.000 description 6
- 230000002745 absorbent Effects 0.000 description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 6
- ITHZDDVSAWDQPZ-UHFFFAOYSA-L barium acetate Chemical compound [Ba+2].CC([O-])=O.CC([O-])=O ITHZDDVSAWDQPZ-UHFFFAOYSA-L 0.000 description 6
- 230000002776 aggregation Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000004220 aggregation Methods 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 3
- 150000001339 alkali metal compounds Chemical class 0.000 description 3
- 150000001341 alkaline earth metal compounds Chemical class 0.000 description 3
- 239000012876 carrier material Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229910000510 noble metal Inorganic materials 0.000 description 3
- 239000002243 precursor Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- CMPGARWFYBADJI-UHFFFAOYSA-L tungstic acid Chemical compound O[W](O)(=O)=O CMPGARWFYBADJI-UHFFFAOYSA-L 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 2
- 229910021536 Zeolite Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 229910052790 beryllium Inorganic materials 0.000 description 2
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 2
- FJDQFPXHSGXQBY-UHFFFAOYSA-L caesium carbonate Chemical compound [Cs+].[Cs+].[O-]C([O-])=O FJDQFPXHSGXQBY-UHFFFAOYSA-L 0.000 description 2
- 229910000024 caesium carbonate Inorganic materials 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000010949 copper Substances 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
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 2
- 238000010304 firing Methods 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
- 150000002736 metal compounds Chemical class 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- DHEQXMRUPNDRPG-UHFFFAOYSA-N strontium nitrate Chemical compound [Sr+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O DHEQXMRUPNDRPG-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 150000003658 tungsten compounds Chemical class 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- TUMCWFMHZOUPDA-UHFFFAOYSA-N 2-ethylsulfanyl-1,3-benzothiazol-6-amine Chemical compound C1=C(N)C=C2SC(SCC)=NC2=C1 TUMCWFMHZOUPDA-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 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
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- XAYGUHUYDMLJJV-UHFFFAOYSA-Z decaazanium;dioxido(dioxo)tungsten;hydron;trioxotungsten Chemical compound [H+].[H+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O XAYGUHUYDMLJJV-UHFFFAOYSA-Z 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 229910052730 francium Inorganic materials 0.000 description 1
- KLMCZVJOEAUDNE-UHFFFAOYSA-N francium atom Chemical compound [Fr] KLMCZVJOEAUDNE-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- -1 iron metals Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 1
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 235000011056 potassium acetate Nutrition 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals 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
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- ONSSQRPDFOMBGE-UHFFFAOYSA-N strontium dinitrate hexahydrate Chemical compound O.O.O.O.O.O.[N+](=O)([O-])[O-].[Sr+2].[N+](=O)([O-])[O-] ONSSQRPDFOMBGE-UHFFFAOYSA-N 0.000 description 1
- YOUIDGQAIILFBW-UHFFFAOYSA-J tetrachlorotungsten Chemical compound Cl[W](Cl)(Cl)Cl YOUIDGQAIILFBW-UHFFFAOYSA-J 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 229910001930 tungsten oxide Inorganic materials 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Landscapes
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、排気ガス浄化用触
媒に関し、特に酸素過剰雰囲気下でのＮＯx の浄化性能
に優れる排気ガス浄化用触媒に関する。The present invention relates to relates to an exhaust gas purifying catalyst, in particular to an exhaust gas purifying catalyst having excellent purification performance of the NO x in an oxygen-rich atmosphere.
【０００２】[0002]
【従来の技術】近年、石油資源の枯渇問題および地球温
暖化の観点から、低燃費自動車の実現が期待されてお
り、特にガソリン自動車に関しては希薄燃焼自動車の開
発が望まれている。希薄燃焼自動車においては、希薄燃
焼走行時の排気ガス雰囲気は、論理空燃状態（以下、
「ストイキ状態」と称す）に比べて酸素過剰雰囲気（以
下、「リーン雰囲気」と称す）となる。リーン雰囲気に
おいて、従来の三元触媒を適応させた場合には、過剰な
酸素の影響からＮＯx 浄化作用が不十分になる問題があ
った。このため酸素過剰雰囲気下においてもＮＯx を浄
化できる触媒の開発が望まれていた。2. Description of the Related Art In recent years, from the viewpoint of depletion of petroleum resources and global warming, realization of fuel-efficient vehicles is expected, and development of lean-burn vehicles is particularly desired for gasoline vehicles. In lean-burn vehicles, the exhaust gas atmosphere during lean-burn operation is based on a logical air-fuel
An oxygen-excess atmosphere (hereinafter, referred to as a “lean atmosphere”) as compared to “stoichiometric state”. In a lean atmosphere, when adapted to a conventional three-way catalyst, NO x purification action from the effects of excess oxygen is a problem which becomes insufficient. Development of a catalyst capable of purifying NO x even in this order under an oxygen-rich atmosphere has been desired.
【０００３】従来より、リーン雰囲気下におけるＮＯx
浄化性能を向上させる触媒は従来より、数多く提案され
ており、大別して二種類ある。一つは排気ガス中のＨＣ
を還元剤としてＮＯx を還元浄化するものであり、もう
一つはリーン雰囲気下でＮＯ x を吸収し、ストイキ状態
あるいは燃料過剰（リッチ）雰囲気下でＮＯx を浄化す
るものである。[0003] Conventionally, NO in a lean atmospherex
Many catalysts have been proposed to improve purification performance.
There are two types. One is HC in exhaust gas
NO as a reducing agentxTo reduce and purify
One is NO under lean atmosphere xAbsorbs the stoichiometric state
Alternatively, NO in a fuel-rich (rich) atmospherexPurify
Things.
【０００４】前者の代表的なものとしては、例えば特開
昭６３−１００９１９号公報に開示された触媒であり、
この触媒は銅（Ｃｕ）をゼオライトに担持した触媒であ
る。A typical example of the former is a catalyst disclosed in JP-A-63-100919.
This catalyst is a catalyst in which copper (Cu) is supported on zeolite.
【０００５】一方、後者の代表的なものとしては、例え
ば特開平５−１６８８６０号公報に開示された触媒であ
り、この触媒はランタン等を白金（Ｐｔ）に担持させて
ランタンをＮＯx 吸収材として用いる触媒である。On the other hand, a typical example of the latter is a catalyst disclosed in Japanese Patent Application Laid-Open No. 5-168860. This catalyst has lanthanum or the like supported on platinum (Pt) and lanthanum is NO x absorbent. It is a catalyst used as.
【０００６】しかし上記特開平５−１６８８６０号公報
に開示された触媒は、ＮＯx 吸収能力が不十分であると
いう問題がある。かかる問題を解決する目的で、例えば
特開平５−２６１２８７号公報、特開平５−３１７６５
２号公報および特開平６−３１１３９号公報において、
アルカリ、アルカリ土類金属を用いる排気ガス浄化用触
媒が開示されている。また、特開平６−１４２５８号公
報および特開平６−２６２０４０号公報には、アルカリ
金属、アルカリ土類金属、希土類金属、鉄金属を含有す
る排気ガス浄化用触媒が開示されている。However the disclosed in Japanese Laid-Open 5-168860 discloses catalysts, there is a problem that absorption of NO x capacity is insufficient. For the purpose of solving such a problem, for example, JP-A-5-261287, JP-A-5-31765
No. 2 and JP-A-6-31139,
An exhaust gas purifying catalyst using an alkali or alkaline earth metal is disclosed. JP-A-6-14258 and JP-A-6-262040 disclose exhaust gas purifying catalysts containing alkali metals, alkaline earth metals, rare earth metals, and iron metals.
【０００７】このＮＯx 吸収反応の主経路を、典型的な
ＮＯx 吸収材であるＢａの場合について示すと、 ＢａＣＯ3 ＋２ＮＯ2 ＋１／２・Ｏ2 →Ｂａ（ＮＯ3 ）
2 ＋ＣＯ2 ：式１（ＮＯx 吸収反応の主経路）であることが報告さ
れており（触媒 Vol. ３８（１９９６）Ｐ４５０〜４５
３）、ＢａＣＯ3 等の炭酸塩は、ＮＯx 吸収反応にとっ
て重要な化学形態であるといえる。The main route of this NO x absorption reaction is shown in the case of Ba, which is a typical NO x absorbent, as follows: BaCO 3 + 2NO 2 + 1/2 · O 2 → Ba (NO 3 )
2 + CO 2 : It has been reported that it is the formula 1 (the main route of the NO x absorption reaction) (Catalyst Vol. 38 (1996) P450-45).
3) Carbonates such as BaCO 3 are important chemical forms for NO x absorption reaction.
【０００８】[0008]
【発明が解決しようとする課題】ところが、これらＮＯ
x 吸収材は、硝酸塩、酢酸塩水溶液等の前駆体状態で、
多孔質担体に含浸後、焼成により分解−固定化して調製
されるため、焼成熱により凝集し、式１に代表される反
応の効率が低下する問題点がある。However, these NO
x Absorber is a precursor state such as nitrate and acetate aqueous solution,
Since the porous carrier is impregnated and fixed by baking after being impregnated with the porous carrier, there is a problem that the agglomeration is caused by baking heat and the efficiency of the reaction represented by Formula 1 is reduced.
【０００９】[0009]
【課題を解決するための手段】本発明者らは、上記課題
を解決するために研究した結果、ＮＯx 吸収材であるア
ルカリ金属および／又はアルカリ土類金属又はそれらの
前駆体とタングステン化合物の両者を水、塩酸などの酸
性溶液に溶解または懸濁させ、これを多孔質体に含浸焼
成することにより、多孔質上でＮＯx 吸収材であるアル
カリ金属および／又はアルカリ土類金属とタングステン
とを複合化させ、焼成時のＮＯx 吸収材の凝集を防ぎ、
式１に示したＮＯx 吸収反応の低下を防ぐことができる
ことを見出し、本発明に到達した。The present inventors Means for Solving the Problems] As a result of studies to solve the above problems, the alkali metal and / or alkaline earth metal or a precursor thereof and the tungsten compound is an absorption of NO x material Both are dissolved or suspended in an acidic solution such as water or hydrochloric acid, and the porous body is impregnated and fired, so that an alkali metal and / or an alkaline earth metal, which is a NO x absorbent, and tungsten are formed on the porous body. To prevent aggregation of the NO x absorbent during firing,
The present inventors have found that a decrease in the NO x absorption reaction shown in Formula 1 can be prevented, and have reached the present invention.
【００１０】すなわち、本発明の排気ガス浄化用触媒
は、多孔質担体と、該多孔質担体に担持した、アルカリ
金属およびアルカリ土類金属から選ばれる１種以上の金
属と、該多孔質担体に担持した白金およびパラジウムの
うち少なくとも１種と、タングステンからなる排気ガス
浄化用触媒であって、該アルカリ金属またはアルカリ土
類金属が、カリウム、セシウム、ストロンチウムおよび
バリウムのうちの少なくとも一種であり、該アルカリ金
属および該アルカリ土類金属から選ばれる１種以上の金
属とタングステンとが、粒子径２０nm以下の高分散複合
体を形成することを特徴とする。更に、本発明の上記排
気ガス浄化用触媒は、空燃比１５〜５０で運転される希
薄燃焼方式の内燃機関に好ましく用いられる。That is, the exhaust gas purifying catalyst of the present invention comprises a porous carrier, at least one metal selected from an alkali metal and an alkaline earth metal supported on the porous carrier, An exhaust gas purifying catalyst comprising at least one of platinum and palladium supported and tungsten, wherein the alkali metal or alkaline earth metal is at least one of potassium, cesium, strontium, and barium; One or more metals selected from alkali metals and the alkaline earth metals and tungsten form a highly dispersed composite having a particle diameter of 20 nm or less. Further, the exhaust gas purifying catalyst of the present invention is preferably used for a lean-burn internal combustion engine operated at an air-fuel ratio of 15 to 50.
【００１１】[0011]
【発明の実施の形態】本発明の排気ガス浄化用触媒に関
し、アルカリ金属および／又は、アルカリ土類金属とタ
ングステンの複合化の形態は明らかでないが、Ｘ線光電
子分光法（ＸＰＳ）による解析によると、タングステン
を担持することで、アルカリ金属および／又はアルカリ
土類金属の結合エネルギーがシフトし、化学結合状態が
変化していることから、アルカリ金属および／又はアル
カリ土類金属とタングステンが複合化していると予測さ
れる（表１）。すなわち、アルカリ金属および／又はア
ルカリ土類金属とタングステンは、複合体を形成してい
ると考えられる。ここで、複合とは、アルカリ金属およ
び／又はアルカリ土類金属原子とタングステン原子が、
お互いに分散混合した状態を意味する。BEST MODE FOR CARRYING OUT THE INVENTION Regarding the exhaust gas purifying catalyst of the present invention, the form of compounding of alkali metal and / or alkaline earth metal with tungsten is not clear, but is analyzed by X-ray photoelectron spectroscopy (XPS). And by supporting tungsten, the binding energy of the alkali metal and / or the alkaline earth metal is shifted and the chemical bonding state is changed, so that the alkali metal and / or the alkaline earth metal and the tungsten are complexed. (Table 1). That is, it is considered that the alkali metal and / or the alkaline earth metal and tungsten form a composite. Here, the composite means that an alkali metal and / or alkaline earth metal atom and a tungsten atom are
It means a state where they are dispersed and mixed with each other.
【００１２】また、アルカリ金属および／又はアルカリ
土類金属の結晶凝集状態を、Ｘ線解析分析（ＸＲＤ）に
より解析すると、タングステンを担持したすべての場合
において、アルカリおよび／又はアルカリ土類金属化合
物のピークが観測されないことが判った。これは、これ
らの金属化合物が、ＸＲＤで観測できる最小粒子径（約
２０nm）より小さい複合体として存在することを示す。
従って、本発明の触媒におけるアルカリおよび／又はア
ルカリ土類金属とタングステンは、触媒中で高度に分散
している。尚、上記アルカリ金属化合物とは、例えばＢ
ａＯ，ＢａＣＯ 3 、Ｂａ（ＯＨ)2又はＢａx ＷY ＯZ 等
の化合物をいう。Further, an alkali metal and / or an alkali
X-ray analysis (XRD) of crystal aggregation state of earth metal
More analysis shows that all cases of tungsten loading
, An alkali and / or alkaline earth metal compound
It was found that no peak was observed. This is this
These metal compounds have a minimum particle size (approximately
20 nm).
Therefore, the alkali and / or catalyst in the catalyst of the present invention can be used.
Lucari earth metal and tungsten are highly dispersed in the catalyst
doing. The alkali metal compound is, for example, B
aO, BaCO Three, Ba (OH)TwoOr BaxWYOZetc
Of the compound.
【００１３】本発明の触媒は、一体構造型担体に担持し
て用いるのが好ましく、本発明の触媒を粉砕してスラリ
ーとし、触媒担体にコートして、例えば４００〜９００
℃の温度で焼成することにより、本発明の排気ガス浄化
用触媒を得ることができる。The catalyst of the present invention is preferably used by being supported on a monolithic carrier. The catalyst of the present invention is pulverized into a slurry, coated on the catalyst carrier and, for example, 400 to 900
By firing at a temperature of ° C., the exhaust gas purifying catalyst of the present invention can be obtained.
【００１４】触媒担体としては、特に多孔質担体が好ま
しく、例えば酸化珪素、ゼオライト、チタニア、ジルコ
ニア、シリカ、アルミナ、シリカ−アルミナ系等を用い
ることができる。As the catalyst carrier, a porous carrier is particularly preferred, and for example, silicon oxide, zeolite, titania, zirconia, silica, alumina, silica-alumina and the like can be used.
【００１５】この触媒担体の形状は、特に制限されない
が、通常はハニカム形状で使用することが好ましく、こ
のハニカム材料としては、一般に例えばセラミックス等
のコージェライト質のものが多く用いられるが、フェラ
イト系ステンレス等の金属材料からなるハニカムを用い
ることも可能であり、更には触媒粉末そのものをハニカ
ム形状に成形しても良い。触媒の形状をハニカム状とす
ることにより、触媒とのような使用方法とすることによ
り、ＮＯｘ吸収・放出のサイクルが極めて有効に成立
し、特に効率の良いＮＯx 浄化が可能となる。Although the shape of the catalyst carrier is not particularly limited, it is generally preferable to use a honeycomb shape. As the honeycomb material, cordierite materials such as ceramics are generally used. It is also possible to use a honeycomb made of a metal material such as stainless steel, and further, the catalyst powder itself may be formed into a honeycomb shape. By the shape of the catalyst and honeycomb, by a method using as a catalyst, the cycle of the NOx absorption and release is satisfied very effectively, thereby enabling particularly efficient the NO x purification.
【００１６】本発明の排気ガス浄化用触媒に用いる貴金
属としては、白金およびパラジウムから選ばれる少なく
とも一種が用いられる。その白金およびパラジウムの担
体への担持量は特に限定されない。通常担持される量
（例えば０．０１〜１５重量％）であればよい。また、
タングステンによるアルカリ金属および／又はアルカリ
土類金属凝集抑制効果は、タングステンが存在すること
により発現し、特にその量を規定するものではないが、
式１に示すＮＯx 吸収量への効果から、アルカリ金属お
よび／又はアルカリ土類金属：タングステンが原子比で
１：０．０１〜１０であることが好ましい。タングステ
ンが少な過ぎると（すなわちアルカリ金属および／又は
アルカリ土類金属対タングステンの原子比が１：０．０
１未満）、担持されたすべてのアルカリ金属、アルカリ
土類金属に対し、凝集抑制効果が働かず、また多すぎる
と（すなわち、アルカリ金属および／又はアルカリ土類
金属対タングステンの原子比が１：１０超）、タングス
テンがＮＯx 吸収活性点を多い、反応を阻害する。As the noble metal used in the exhaust gas purifying catalyst of the present invention, at least one selected from platinum and palladium is used. The amount of platinum and palladium supported on the carrier is not particularly limited. It is sufficient that the amount is usually carried (for example, 0.01 to 15% by weight). Also,
The effect of tungsten to suppress the aggregation of alkali metal and / or alkaline earth metal is manifested by the presence of tungsten and does not particularly define the amount thereof.
From the effect on the NO x absorption shown in Formula 1, it is preferable that the atomic ratio of alkali metal and / or alkaline earth metal: tungsten is 1: 0.01-10. If too little tungsten is present (i.e., the atomic ratio of alkali metal and / or alkaline earth metal to tungsten is 1: 0.0
When the atomic ratio of the alkali metal and / or the alkaline earth metal to tungsten is 1: 1, the coagulation suppressing effect does not work on all the supported alkali metals and alkaline earth metals. 10 or more), tungsten has many NO x absorption active sites and inhibits the reaction.
【００１７】また、アルカリ金属および／又はアルカリ
土類金属とタングステンの合計含有量は１〜１２０ｇ／
ｃｆである。１未満であると、式１の反応が十分進行せ
ず不都合である。また、１２０を超えると、アルカリ金
属、アルカリ土類金属、タングステンが貴金属をおおい
貴金属が働かなくなるため不都合である。The total content of alkali metal and / or alkaline earth metal and tungsten is 1 to 120 g /
cf. If it is less than 1, the reaction of Formula 1 does not proceed sufficiently, which is inconvenient. On the other hand, if it exceeds 120, the alkali metal, alkaline earth metal, and tungsten cover the noble metal, and the noble metal does not work, which is inconvenient.
【００１８】前記、触媒調製に用いるタングステン化合
物は、その化合物形態については特に限定される物では
ないが例えば、パラタングステン酸アンモニウム、塩化
タングステン、タングステン酸、酸化タングステン等の
化合物がが好都合に用いられる。The form of the tungsten compound used in the preparation of the catalyst is not particularly limited. For example, compounds such as ammonium paratungstate, tungsten chloride, tungstic acid, and tungsten oxide are advantageously used. .
【００１９】本発明の排気ガス上記用触媒に用いるＮＯ
x 吸収材としては、アルカリ金属、アルカリ土類金属か
ら選ばれる金属の化合物を用いることができる。アルカ
リ金属としてはリチウム、カリウム、ルビジウム、セシ
ウム、フランシウムが挙げられ、カリウムおよびセシウ
ムが好ましい。アルカリ土類金属としてはベリウム、マ
グネシウム、カルシウム、ストロンチウムが挙げられ、
ベリウム、カルシウム又はストロンチウムが好ましく用
いられる。NO used for the above catalyst for exhaust gas of the present invention
As the x- absorbing material, a compound of a metal selected from an alkali metal and an alkaline earth metal can be used. Examples of the alkali metal include lithium, potassium, rubidium, cesium, and francium, and potassium and cesium are preferred. Alkaline earth metals include beryllium, magnesium, calcium, strontium,
Beryllium, calcium or strontium is preferably used.
【００２０】触媒調製に用いる上記のアルカリおよび／
又はアルカリ土類金属化合物は、その金属化合物形態に
ついては特に限定される物ではない。例えば、金属その
まま又はその前駆体、酢酸バリウム、硝酸ストロンチウ
ム、塩化カルシウム、炭酸セシウム、硝酸カリウム等と
して用いられる。The above-mentioned alkali and / or
Alternatively, the alkaline earth metal compound is not particularly limited in its metal compound form. For example, it is used as the metal itself or its precursor, barium acetate, strontium nitrate, calcium chloride, cesium carbonate, potassium nitrate and the like.
【００２１】本発明の排気ガス浄化用触媒では、多孔質
の触媒担体上でＮＯx 吸収材であるアルカリ金属および
／又はアルカリ土類金属とタングステンが複合化するこ
とで、焼成時のアルカリ金属、アルカリ土類金属の凝集
を防ぎ、式１に示したＮＯx吸収反応の低下を防ぐこと
ができる。In the exhaust gas purifying catalyst of the present invention, the alkali metal and / or alkaline earth metal as the NO x absorbent is combined with tungsten on the porous catalyst carrier, so that the alkali metal during calcination, Aggregation of alkaline earth metals can be prevented, and a decrease in the NO x absorption reaction shown in Formula 1 can be prevented.
【００２２】[0022]
【実施例】以下、実施例及び比較例により本発明を具体
的に説明する。 実施例１ １％硝酸水溶液９００ｇにベーマイトアルミナ１０ｇを
混合攪拌して得られたアルミナゾルと、活性γアルミナ
粉末（１０００ｇ）を磁性ボールミルに投入し、粉砕し
てアルミナスラリーを得た。このスラリー液をコーディ
エライト質モノリス担体（１Ｌ，４００セル）に付着さ
せ、４００℃で１時間焼成してコート層重量１００ｇ／
Ｌ担体を得た。得られたコート量重量１００ｇ／Ｌ担体
材料に、タングステン酸（Ｈ2 ＷＯ4）１００ｇを１Ｌ
の蒸留水に加え、加熱しながら攪拌した水溶液に含浸
し、乾燥した後、空気中で４００℃、１時間の焼成を行
った。当該材料中のタングステン含有量は、１．４ｇ／
Ｌであった。得られた担体材料を１５重量％の酢酸バリ
ウム水溶液（１５００ｍｌ）に含浸し、乾燥した後、空
気中で４００℃、１時間の焼成を行った。当該材料中の
バリウム含有量は、１５．０ｇ／Ｌであった。得られた
担体材料に、ジニトロジアミン白金の混合水溶液を含浸
し乾燥した後、空気中で４００℃、１時間の焼成を行な
い排気ガス浄化用触媒を得た。当該触媒中の白金の含有
量は、１．１６ｇ／Ｌであった。得られた触媒につい
て、ＸＲＤにより解析した。その結果、アルカリおよび
／又はアルカリ土類金属化合物のピークは観測されなか
った。The present invention will be specifically described below with reference to examples and comparative examples. Example 1 An alumina sol obtained by mixing and stirring 10 g of boehmite alumina in 900 g of a 1% aqueous nitric acid solution and activated gamma alumina powder (1000 g) were charged into a magnetic ball mill and pulverized to obtain an alumina slurry. This slurry liquid was adhered to a cordierite-based monolithic carrier (1 L, 400 cells), baked at 400 ° C. for 1 hour, and weighed 100 g / coat layer.
L carrier was obtained. 1 g of 100 g of tungstic acid (H 2 WO 4 ) was added to the obtained coat weight of 100 g / L carrier material.
Was added to distilled water, impregnated with an aqueous solution stirred while heating, dried, and then calcined in air at 400 ° C. for 1 hour. The tungsten content in the material is 1.4 g /
L. The obtained carrier material was impregnated with a 15% by weight aqueous barium acetate solution (1500 ml), dried, and then calcined at 400 ° C. for 1 hour in air. The barium content in the material was 15.0 g / L. The resulting carrier material was impregnated with a mixed aqueous solution of dinitrodiamine platinum and dried, and then calcined in air at 400 ° C. for 1 hour to obtain an exhaust gas purifying catalyst. The platinum content in the catalyst was 1.16 g / L. The obtained catalyst was analyzed by XRD. As a result, no peak of the alkali and / or alkaline earth metal compound was observed.
【００２３】実施例２ 酢酸バリウムの代わりに硝塩化ストロンチウム六水和物
を用いること以外は、実施例１と同様にして排気ガス浄
化用触媒を得た。Example 2 An exhaust gas purifying catalyst was obtained in the same manner as in Example 1 except that strontium nitrate hexahydrate was used instead of barium acetate.
【００２４】実施例３ 酢酸バリウムの代わりにクエン酸カルシウム四水和物を
用いること以外は、実施例１と同様にして排気ガス浄化
用触媒を得た。Example 3 An exhaust gas purifying catalyst was obtained in the same manner as in Example 1 except that calcium citrate tetrahydrate was used instead of barium acetate.
【００２５】実施例４ 酢酸バリウムの代わりに炭酸セシウムを用いること以外
は、実施例１と同様にして排気ガス浄化用触媒を得た。Example 4 An exhaust gas purifying catalyst was obtained in the same manner as in Example 1 except that cesium carbonate was used instead of barium acetate.
【００２６】実施例５ 酢酸バリウムの代わりに酢酸カリウムを用いること以外
は、実施例１と同様にして排気ガス浄化用触媒を得た。Example 5 An exhaust gas purifying catalyst was obtained in the same manner as in Example 1 except that potassium acetate was used instead of barium acetate.
【００２７】実施例６ ジニトロジアミン白金の混合水溶液の代わりに硝酸パラ
ジウムを用いること以外は、実施例１と同様にして排気
ガス浄化用触媒を得た。Example 6 An exhaust gas purifying catalyst was obtained in the same manner as in Example 1, except that palladium nitrate was used instead of the mixed aqueous solution of dinitrodiamine platinum.
【００２８】実施例７ 活性γアルミナの代わりに、アモルファス酸化チタンを
用いること以外は、実施例１と同様にして排気ガス浄化
用触媒を得た。Example 7 An exhaust gas purifying catalyst was obtained in the same manner as in Example 1 except that amorphous titanium oxide was used instead of activated gamma alumina.
【００２９】比較例１〜７ タングステン酸の担持を行わないこと以外は、実施例１
〜７と同様にして排気ガス浄化用触媒を得た。Comparative Examples 1 to 7 Example 1 was repeated except that tungstic acid was not supported.
In the same manner as in Examples 7 to 7, an exhaust gas purifying catalyst was obtained.
【００３０】実験例１ 上記実施例１〜７および比較例１〜７の触媒について、
以下の条件で初期及び耐久後の触媒活性評価を行った。Experimental Example 1 The catalysts of Examples 1 to 7 and Comparative Examples 1 to 7 were
Under the following conditions, initial and after endurance catalyst activity evaluations were performed.
【００３１】耐久条件 エンジン４４００ｃｃの排気系に触媒を装着し、６００
℃で、５０時間運転し、耐久を行った。Endurance conditions A catalyst was attached to the exhaust system of 4400 cc engine,
The operation was performed at 50 ° C. for 50 hours to endurance.
【００３２】評価条件 触媒活性評価は、排気量２０００ｃｃのエンジンの排気
系に各種触媒を装着し、Ａ／Ｆ＝１４．６（ストイキ状
態）で３０秒間、その後Ａ／Ｆ＝２２（リーン状態）で
３０秒間の１サイクルを行い、各々平均転化率を測定
し、このＡ／Ｆ＝１４．６の場合の平均転化率とＡ／Ｆ
＝２２の場合の平均転化率とを平均してトータル転化率
とした。この評価を、初期及び耐久後に各々行った。平
均転化率の算出法は以下の通りである。Evaluation Conditions The catalyst activity was evaluated by installing various catalysts in the exhaust system of a 2000 cc engine with A / F = 14.6 (stoichiometric state) for 30 seconds, and then A / F = 22 (lean state). , One cycle of 30 seconds was performed, and the average conversion was measured, and the average conversion and A / F when A / F = 14.6 were measured.
= 22 and the average conversion was averaged to obtain the total conversion. This evaluation was performed at the initial stage and after the endurance. The method of calculating the average conversion is as follows.
【数１】 (Equation 1)
【００３３】トータル転化率として得られた触媒活性評
価結果を表１に示す。比較例に比べ、実施例は、触媒活
性が高く、後述する本発明の効果を確認することができ
る。Table 1 shows the catalytic activity evaluation results obtained as the total conversion. As compared with the comparative example, the example has a higher catalytic activity, and can confirm the effects of the present invention described later.
【００３４】[0034]
【表１】 [Table 1]
【００３５】[0035]
【発明の効果】本発明の排気ガス浄化用触媒は、特にＮ
Ｏx 吸収剤であるアルカリ又はアルカリ土類金属とタン
グステンとが複合化して高分散複合体を含有せしめるよ
うに構成したものであるから、ＮＯx 浄化性能を著しく
高める効果を奏する。又、本発明の触媒は、特にリーン
雰囲気下でＮＯx を効率よく浄化できる効果を奏するの
で、例えば空燃比１５〜５０で運転される希薄燃焼方式
の内燃機関に好ましく使用できる。The exhaust gas purifying catalyst of the present invention is particularly suitable for
Since the structure is such that an alkali or alkaline earth metal, which is an O x absorbent, and tungsten are compounded to contain a highly dispersed complex, an effect of significantly improving NO x purification performance is achieved. Further, the catalyst of the present invention, particularly since an effect which can efficiently purify NO x in lean atmosphere, for example can be preferably used in an internal combustion engine of the lean burn operating at air-fuel ratio from 15 to 50.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｂ０１Ｄ 53/36 １０２Ｈ ──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. 6 Identification code FI B01D 53/36 102H
Claims (5)
た、アルカリ金属およびアルカリ土類金属から選ばれる
１種以上の金属と、該多孔質担体に担持した白金および
パラジウムのうち少なくとも１種と、タングステンを含
んでなる排気ガス浄化用触媒であって、該アルカリ金属
またはアルカリ土類金属が、カリウム、セシウム、スト
ロンチウムおよびバリウムのうちの少なくとも一種であ
り、該アルカリおよび該アルカリ土類から選ばれる１種
以上の金属とタングステンとが、粒子径２０nm以下の高
分散複合体を形成していることを特徴とする排気ガス浄
化用触媒。1. A porous carrier, at least one metal selected from alkali metals and alkaline earth metals supported on the porous carrier, and at least one of platinum and palladium supported on the porous carrier And an exhaust gas purifying catalyst comprising tungsten, wherein the alkali metal or alkaline earth metal is at least one of potassium, cesium, strontium and barium, and is selected from the alkali and the alkaline earth. The exhaust gas purifying catalyst according to claim 1, wherein the at least one metal and tungsten form a highly dispersed composite having a particle diameter of 20 nm or less.
方式の内燃機関に用いる請求項１記載の排気ガス浄化用
触媒。2. The exhaust gas purifying catalyst according to claim 1, which is used for a lean burn internal combustion engine operated at an air-fuel ratio of 15 to 50.
金属対タングステンの原子比が、１対０．０１〜１０で
ある、請求項１又は２に記載の排気ガス浄化用触媒。3. The exhaust gas purifying catalyst according to claim 1, wherein the atomic ratio of alkali metal and / or alkaline earth metal to tungsten is 1 to 0.01 to 10.
ート層として備えたことを特徴とする排気ガス浄化用触
媒。4. An exhaust gas purifying catalyst comprising the catalyst according to claim 1 provided as a coating layer on a catalyst carrier.
状モノリス担体基材であることを特徴とする排気ガス浄
化用触媒。5. An exhaust gas purifying catalyst, wherein the catalyst carrier according to claim 4 is a honeycomb monolith carrier substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9342913A JPH11169713A (en) | 1997-12-12 | 1997-12-12 | Catalyst for purification of exhaust gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9342913A JPH11169713A (en) | 1997-12-12 | 1997-12-12 | Catalyst for purification of exhaust gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11169713A true JPH11169713A (en) | 1999-06-29 |
Family
ID=18357498
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9342913A Withdrawn JPH11169713A (en) | 1997-12-12 | 1997-12-12 | Catalyst for purification of exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11169713A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001094008A1 (en) * | 2000-06-06 | 2001-12-13 | Toyota Jidosha Kabushiki Kaisha | Catalyst for emission gas clarification |
| JP2003071289A (en) * | 2001-08-30 | 2003-03-11 | Toyota Central Res & Dev Lab Inc | Nitrogen oxide reduction catalyst and method for reducing nitrogen oxide |
| JP2005161109A (en) * | 2003-11-28 | 2005-06-23 | Mitsubishi Heavy Ind Ltd | Exhaust gas treatment catalyst and its producing method |
-
1997
- 1997-12-12 JP JP9342913A patent/JPH11169713A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001094008A1 (en) * | 2000-06-06 | 2001-12-13 | Toyota Jidosha Kabushiki Kaisha | Catalyst for emission gas clarification |
| JP2003071289A (en) * | 2001-08-30 | 2003-03-11 | Toyota Central Res & Dev Lab Inc | Nitrogen oxide reduction catalyst and method for reducing nitrogen oxide |
| JP2005161109A (en) * | 2003-11-28 | 2005-06-23 | Mitsubishi Heavy Ind Ltd | Exhaust gas treatment catalyst and its producing method |
| JP4727140B2 (en) * | 2003-11-28 | 2011-07-20 | 三菱重工業株式会社 | Exhaust gas treatment catalyst and method for producing the same |
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| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Application deemed to be withdrawn because no request for examination was validly filed |
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