JP4923412B2 - Exhaust gas purification catalyst - Google Patents
Exhaust gas purification catalyst Download PDFInfo
- Publication number
- JP4923412B2 JP4923412B2 JP2005049740A JP2005049740A JP4923412B2 JP 4923412 B2 JP4923412 B2 JP 4923412B2 JP 2005049740 A JP2005049740 A JP 2005049740A JP 2005049740 A JP2005049740 A JP 2005049740A JP 4923412 B2 JP4923412 B2 JP 4923412B2
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- nox
- exhaust gas
- upstream
- supported
- 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.)
- Expired - Fee Related
Links
- 239000003054 catalyst Substances 0.000 title claims description 85
- 238000000746 purification Methods 0.000 title claims description 25
- 238000011144 upstream manufacturing Methods 0.000 claims description 41
- 229910052763 palladium Inorganic materials 0.000 claims description 31
- 229910052697 platinum Inorganic materials 0.000 claims description 31
- 239000000758 substrate Substances 0.000 claims description 22
- 239000011232 storage material Substances 0.000 claims description 13
- 229910052703 rhodium Inorganic materials 0.000 claims description 12
- 229910052783 alkali metal Inorganic materials 0.000 claims description 4
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 4
- 239000011358 absorbing material Substances 0.000 claims description 2
- 150000001340 alkali metals Chemical class 0.000 claims description 2
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 2
- 229910002089 NOx Inorganic materials 0.000 claims 2
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 191
- 239000007789 gas Substances 0.000 description 49
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 41
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 31
- 239000000463 material Substances 0.000 description 27
- 229910000510 noble metal Inorganic materials 0.000 description 19
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 17
- 239000002585 base Substances 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 13
- 239000007864 aqueous solution Substances 0.000 description 11
- 238000006722 reduction reaction Methods 0.000 description 10
- 239000010948 rhodium Substances 0.000 description 10
- 230000010757 Reduction Activity Effects 0.000 description 8
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- IWOUKMZUPDVPGQ-UHFFFAOYSA-N barium nitrate Chemical compound [Ba+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O IWOUKMZUPDVPGQ-UHFFFAOYSA-N 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 6
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 6
- 239000002002 slurry Substances 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 5
- 238000011068 loading method Methods 0.000 description 5
- 239000008188 pellet Substances 0.000 description 5
- 230000001603 reducing effect Effects 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 229910052744 lithium Inorganic materials 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 235000010333 potassium nitrate Nutrition 0.000 description 3
- 239000004323 potassium nitrate Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- -1 alkali metal salt Chemical class 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
- 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
- 238000005245 sintering Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 1
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 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
- 238000007796 conventional method Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000010304 firing Methods 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
- 230000001771 impaired effect Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000003801 milling Methods 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
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000002360 preparation method Methods 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
- 150000003839 salts Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 1
Images
Description
本発明は、自動車等の内燃機関から排出される排ガスを浄化する排ガス浄化用触媒に関するものであり、詳しくは、窒素酸化物（ＮＯｘ）を効果的に浄化する排ガス浄化触媒に関する。 The present invention relates to an exhaust gas purifying catalyst that purifies exhaust gas discharged from an internal combustion engine such as an automobile, and more particularly to an exhaust gas purifying catalyst that effectively purifies nitrogen oxides (NOx).
自動車分野において、リーンバーンエンジンの使用の拡大が図られる中、リーン領域でＮＯｘの排出を低減できるＮＯｘ吸蔵還元触媒が実用化されている。ＮＯｘ吸蔵還元触媒は、アルミナ等の担体に貴金属およびアルカリ金属元素やアルカリ土類金属元素（ＮＯｘ吸蔵材）を担持させたものである。リーン状態では、貴金属上でＮＯｘを酸化し、隣接するＮＯｘ吸蔵材と結合して硝酸塩を形成することにより、ＮＯｘを吸蔵する。一方、ストイキ〜リッチ状態では、硝酸塩が分解されて気相に放出されたＮＯｘを貴金属上で還元性ガスと反応させて、または、放出される前に硝酸塩を分解して、窒素に還元する。ＮＯｘの吸蔵と還元とを繰り返すことにより、ＮＯｘが浄化される。 While the use of lean burn engines is being expanded in the automotive field, NOx storage reduction catalysts that can reduce NOx emissions in the lean region have been put into practical use. The NOx occlusion reduction catalyst is obtained by supporting a noble metal, an alkali metal element, or an alkaline earth metal element (NOx occlusion material) on a support such as alumina. In the lean state, NOx is oxidized on the noble metal and combined with the adjacent NOx storage material to form nitrate, thereby storing NOx. On the other hand, in the stoichiometric to rich state, the NOx decomposed and released into the gas phase is reacted with a reducing gas on the noble metal, or the nitrate is decomposed and reduced to nitrogen before being released. By repeating NOx occlusion and reduction, NOx is purified.
近年、さらなるエミッション規制に伴い、還元時（ストイキ〜リッチ状態で）のＮＯｘ排出量の低減が求められている。ところが、ＮＯｘ吸蔵材に吸蔵されたＮＯｘを還元する際には、ＮＯｘ吸蔵材から気相に放出されたＮＯｘが全て浄化しきれずに一部排出されるという問題がある。そこで、特許文献１には、ＮＯｘ吸蔵還元触媒の下流側に三元触媒を配置して、ＮＯｘ吸蔵還元触媒から排出されたＮＯｘを還元する排気ガス浄化装置が開示されている。
In recent years, with further emission regulations, reduction of NOx emission during reduction (in a stoichiometric to rich state) has been demanded. However, when NOx occluded in the NOx occlusion material is reduced, there is a problem in that all of the NOx released from the NOx occlusion material into the gas phase is not completely purified but is partially discharged. Therefore,
また、Ｐｔは、ＮＯｘ吸蔵還元反応に有効な貴金属であるが、リーン雰囲気での耐熱性に劣る。そのため、リーン雰囲気で使用されると、Ｐｔがシンタリングしやすいという問題がある。さらに、貴金属と併用されるＮＯｘ吸蔵材は塩基性物質であるため、Ｐｔ等の貴金属の活性を低下させるという問題がある。
本発明は、上記問題点に鑑み、新規な構成により、ストイキ〜リッチ雰囲気においてＮＯｘ吸蔵材から気相に放出されるＮＯｘの排出を効果的に抑制することができる排ガス浄化触媒を提供することを目的とする。 In view of the above problems, the present invention provides an exhaust gas purification catalyst that can effectively suppress the emission of NOx released from the NOx storage material into the gas phase in a stoichiometric to rich atmosphere with a novel configuration. Objective.
本発明の排ガス浄化触媒は、担体基材と、該担体基材に形成された触媒担持層と、該触媒担持層に担持されたＰｔ、Ｐｄ、ＲｈおよびＮＯｘ吸蔵材と、を有する排ガス浄化触媒であって、
排ガス流の上流側から下流側にかけて配置された上流部触媒と下流部触媒とを備え、
前記上流部触媒はＰｔ、ＰｄおよびＮＯｘ吸蔵材を含み、
前記下流部触媒はＰｔおよびＰｄを含まずＲｈおよびＮＯｘ吸蔵材を含み、Ｒｈは前記上流部触媒よりも該下流部触媒に高濃度担持されていることを特徴とする。
The exhaust gas purifying catalyst of the present invention comprises a support base material, a catalyst support layer formed on the support base material, and a Pt, Pd, Rh, and NOx storage material supported on the catalyst support layer. Because
An upstream catalyst and a downstream catalyst arranged from the upstream side to the downstream side of the exhaust gas flow,
The upstream catalyst includes Pt, Pd, and NOx storage material,
Said downstream portion catalyst comprises a Rh and NOx-absorbing material does not contain Pt and Pd, Rh is characterized in that it is a high concentration carried to the downstream portion catalyst than the upstream portion catalyst.
これ以下、「上流部触媒」を単に「上流部」、「下流部触媒」を単に「下流部」、と略記することもある。 Hereinafter, the “upstream catalyst” may be simply abbreviated as “upstream part”, and the “downstream catalyst” may be simply abbreviated as “downstream part”.
なお、「高濃度担持」とは、担体基材の上流部と下流部とを比較した場合に、一方の担持濃度が他方の担持濃度よりも高いこと、さらには、ある成分の担持濃度が他の成分の担持濃度よりも高いこと、を示しており、担持濃度がある一定濃度以上であることを示す言葉ではない。 Note that “high concentration loading” means that when the upstream portion and the downstream portion of the carrier substrate are compared, the loading concentration of one component is higher than the loading concentration of the other, and the loading concentration of a certain component is the other. This is not a word indicating that the supported concentration is higher than a certain concentration.
本発明の排ガス浄化触媒によれば、Ｒｈを担体基材の下流部で高濃度担持することにより、ストイキあるいはリッチ雰囲気で気相に放出されるＮＯｘの還元活性が向上する。そのため、気相に放出されるＮＯｘの排出を効果的に抑制することができる。 According to the exhaust gas purifying catalyst of the present invention, the reducing activity of NOx released into the gas phase in a stoichiometric or rich atmosphere is improved by supporting Rh at a high concentration in the downstream portion of the carrier substrate. Therefore, it is possible to effectively suppress the discharge of NOx released into the gas phase.
さらに、ＰｔおよびＰｄを担体基材の上流部で高濃度担持することにより、リーン雰囲気でのＰｔの耐熱性が向上する。その結果、ＮＯｘの吸蔵量およびＮＯｘの浄化性能が向上する。 Further, by supporting Pt and Pd at a high concentration in the upstream portion of the carrier base material, the heat resistance of Pt in a lean atmosphere is improved. As a result, the storage amount of NOx and the purification performance of NOx are improved.
本発明の排ガス浄化触媒は、担体基材と、担体基材に形成された触媒担持層と、その触媒担持層に担持されたＰｔ、Ｐｄ、ＲｈおよびＮＯｘ吸蔵材と、を有する。すなわち、本発明の排ガス浄化触媒は、リーン雰囲気時にＮＯｘを吸蔵して、ストイキあるいはリッチ雰囲気時に吸蔵したＮＯｘを還元するタイプの触媒である。 The exhaust gas purifying catalyst of the present invention has a support base, a catalyst support layer formed on the support base, and a Pt, Pd, Rh, and NOx occlusion material supported on the catalyst support layer. That is, the exhaust gas purifying catalyst of the present invention is a type of catalyst that stores NOx in a lean atmosphere and reduces NOx stored in a stoichiometric or rich atmosphere.
担体基材には、従来から用いられているセラミックス製や金属製のハニカム状の構造体などを用いればよい。担体基材に触媒担持層を形成するには、たとえば、ハニカム状の構造体に、多孔質酸化物を含むスラリーをウォッシュコートし、それを焼成して触媒担持層を形成し、さらに、その触媒担持層に吸着担持法あるいは吸水担持法でＰｔ、Ｐｄ、ＲｈおよびＮＯｘ吸蔵材を担持すればよい。多孔質酸化物としては、アルミナ、シリカ、チタニア、セリア、ジルコニア、あるいは、これらの複数種からなるセリア−ジルコニア固溶体などの複合酸化物が使用可能であり、これらのうち一種または複数種を用いることができる。もちろん、多孔質酸化物に予めＰｔ、Ｐｄ、ＲｈやＮＯｘ吸蔵材の一部または全部を担持させて、触媒担持層を形成してもよい。 For the carrier substrate, a conventionally used ceramic or metal honeycomb-like structure may be used. In order to form the catalyst support layer on the carrier substrate, for example, a honeycomb-shaped structure is washed with a slurry containing a porous oxide and fired to form a catalyst support layer. The Pt, Pd, Rh, and NOx storage material may be supported on the support layer by an adsorption support method or a water absorption support method. As the porous oxide, alumina, silica, titania, ceria, zirconia, or a composite oxide such as ceria-zirconia solid solution composed of a plurality of these can be used, and one or more of these can be used. Can do. Of course, part or all of Pt, Pd, Rh and NOx occlusion material may be supported on the porous oxide in advance to form the catalyst supporting layer.
この際、触媒層のコート量は、性能上、１５０〜２７０ｇ／Ｌ（担体基材１Ｌ当たり：以下同様）であるのが好ましい。 At this time, the coating amount of the catalyst layer is preferably 150 to 270 g / L (per 1 L of the carrier substrate: the same applies hereinafter) in view of performance.
ＮＯｘ吸蔵材は、アルカリ金属元素およびアルカリ土類金属元素から選ばれる少なくとも一種を用いることができる。具体的には、リチウム、ナトリウム、カリウム、ルビジウム、セシウム、フランシウム、バリウム、ベリリウム、マグネシウム、カルシウム、ストロンチウム、が挙げられる。ＮＯｘ吸蔵材を触媒担持層に担持する際には、アルカリ金属塩、アルカリ土類金属塩の水溶液が利用できる。 As the NOx storage material, at least one selected from alkali metal elements and alkaline earth metal elements can be used. Specific examples include lithium, sodium, potassium, rubidium, cesium, francium, barium, beryllium, magnesium, calcium, and strontium. When the NOx storage material is supported on the catalyst support layer, an aqueous solution of an alkali metal salt or an alkaline earth metal salt can be used.
この際、ＮＯｘ吸蔵材の担持量は、性能上、０．０５〜１．６ｍｏｌ／Ｌ（担体基材１Ｌ当たり：以下同様）であるのが好ましく、さらに好ましくは、０．０５〜１．５ｍｏｌ／Ｌである。 At this time, the supported amount of the NOx occlusion material is preferably 0.05 to 1.6 mol / L (per carrier substrate 1L: the same applies hereinafter), more preferably 0.05 to 1.5 mol in terms of performance. / L.
ところで、既に説明したが、リーン雰囲気時にＮＯｘ吸蔵材に吸蔵されたＮＯｘは、ストイキ〜リッチ雰囲気時に、（１）硝酸塩が分解されて気相に放出されたＮＯｘを貴金属上で還元性ガスと反応させて窒素に還元する、または、（２）気相に放出される前に硝酸塩を分解して窒素に還元する、という２つの方法によりＮＯｘの浄化を行っている。そこで、本発明者は、（１）（２）の各方法に対して有効な貴金属（Ｐｔ、Ｐｄ、Ｒｈ）の担持構成を見出した。また、ＮＯｘ吸蔵材に吸蔵されたＮＯｘを還元する際に還元されなかったＮＯｘが排出されるのは、ＮＯｘ吸蔵還元触媒の貴金属の還元活性が不足するためであることに着目した。 By the way, as already explained, the NOx occluded in the NOx occlusion material in the lean atmosphere is, in a stoichiometric to rich atmosphere, (1) the NOx decomposed to the gas phase reacts with the reducing gas on the noble metal. NOx purification is performed by two methods of reducing to nitrogen, or (2) decomposing nitrate and reducing to nitrogen before being released into the gas phase. Therefore, the present inventor has found a supporting structure of noble metals (Pt, Pd, Rh) effective for the methods (1) and (2). Further, attention was paid to the fact that NOx that was not reduced when NOx occluded in the NOx occlusion material was reduced was due to the lack of noble metal reduction activity of the NOx occlusion reduction catalyst.
図３は、貴金属（Ｒｈ、Ｐｄ、Ｐｔ）がアルミナ（ＭＩ２００）に担持されたペレットのＮＯｘ還元活性を示すグラフであって、縦軸のＴＯＦ［１／ｓ］は、表面原子１個当たりの反応速度、すなわち、表面に露出した貴金属原子１個当たりの実質的な活性を評価している。各ペレットは、電気炉で７５０℃５時間耐久後に評価を行った。図３によれば、ＲｈのＮＯｘ還元活性は、ＰｄやＰｔに比べ、著しく高い値を示している。 FIG. 3 is a graph showing the NOx reduction activity of pellets in which noble metals (Rh, Pd, Pt) are supported on alumina (MI200), and the vertical axis TOF [1 / s] is the value per one surface atom. The reaction rate, ie the substantial activity per noble metal atom exposed on the surface, is evaluated. Each pellet was evaluated after durability at 750 ° C. for 5 hours in an electric furnace. According to FIG. 3, the NOx reduction activity of Rh shows a remarkably high value compared with Pd and Pt.
そこで、本発明の排ガス浄化触媒では、Ｒｈが、排ガス流の下流側に配置される担体基材の下流部に高濃度担持されている構成とした。担体基材の下流部でＲｈを高濃度担持することにより、上流部のＮＯｘ吸蔵材から気相に放出されるが上流部では還元しきれずに下流側へ排出されるＮＯｘを、下流部で還元することができる。下流部は、ＮＯｘ還元活性の高いＲｈを上流部よりも高濃度で担持しているため、上流部のＮＯｘ吸蔵材から気相に放出されたＮＯｘを効果的に還元することができる。したがって、ＮＯｘの還元時に排ガス浄化触媒から排出されるＮＯｘの量が低減される。 Therefore, the exhaust gas purifying catalyst of the present invention has a configuration in which Rh is supported at a high concentration in the downstream portion of the carrier substrate disposed on the downstream side of the exhaust gas flow. By supporting a high concentration of Rh in the downstream part of the carrier base material, NOx released from the upstream NOx storage material into the gas phase but not fully reduced in the upstream part is reduced in the downstream part. can do. Since the downstream portion carries Rh having a higher NOx reduction activity at a higher concentration than the upstream portion, NOx released from the upstream portion of the NOx storage material into the gas phase can be effectively reduced. Therefore, the amount of NOx discharged from the exhaust gas purification catalyst when NOx is reduced is reduced.
Ｒｈは、担体基材の上流部よりも下流部で高濃度となるように担持されていればよく、また、下流部において他の貴金属成分（Ｐｔ、Ｐｄ等）よりも高濃度で担持されていればよい。したがって、ＲｈとＰｔやＰｄとを併用してもよいが、貴金属成分として、下流部にＲｈのみが担持されている（ＰｔやＰｄを併用しない）状態が、ＮＯｘ還元活性を高める上で、特に好ましい。 Rh is only required to be supported at a higher concentration in the downstream portion than the upstream portion of the carrier substrate, and is supported at a higher concentration than other noble metal components (Pt, Pd, etc.) in the downstream portion. Just do it. Therefore, although Rh may be used in combination with Pt or Pd, a state in which only Rh is supported in the downstream portion as a noble metal component (without using Pt or Pd in combination) is particularly effective for enhancing NOx reduction activity. preferable.
この際、ＰｔおよびＰｄは、排ガス流の上流側に配置される担体基材の上流部で高濃度担持されているのが好ましい。ＰｔとＰｄとを担体基材の上流側で併用することにより、Ｐｔのリーン雰囲気での耐熱性が向上する。その結果、触媒作製時の加熱工程（乾燥や焼成）やリーン雰囲気での使用時に発生するＰｔのシンタリングが抑制され、ＮＯｘ吸蔵性能およびＮＯｘ浄化性能が共に向上する。上流部のＮＯｘ吸蔵性能が上がれば、ストイキ〜リーン雰囲気時に気相に放出されるＮＯｘ量も多くなるが、本発明の排ガス浄化触媒では、下流部のＮＯｘ還元活性が高い（前述）。そのため、気相に放出されて上流部から下流部へ排出されたＮＯｘは下流部で良好に浄化されるため、好ましい。 At this time, it is preferable that Pt and Pd are supported at a high concentration in the upstream portion of the carrier base disposed upstream of the exhaust gas flow. By using Pt and Pd in combination on the upstream side of the carrier substrate, the heat resistance of Pt in a lean atmosphere is improved. As a result, sintering of Pt generated during the heating process (drying and firing) during catalyst preparation and use in a lean atmosphere is suppressed, and both NOx occlusion performance and NOx purification performance are improved. If the upstream NOx occlusion performance is improved, the amount of NOx released to the gas phase in the stoichiometric to lean atmosphere increases, but the exhaust gas purifying catalyst of the present invention has high downstream NOx reduction activity (as described above). Therefore, NOx discharged into the gas phase and discharged from the upstream portion to the downstream portion is preferable because it is well purified in the downstream portion.
なお、図４は、貴金属（Ｐｄ、Ｐｔ）がアルミナ（ＭＩ２００）に担持されたペレットのＮＯｘ吸蔵量を示すグラフである。各ペレットは、ＰｔとＰｄの担持量が、それぞれ、Ｐｔ／Ｐｄ＝２／０、０／５、１／２（重量比）となるように調製され、各ペレットを電気炉で７５０℃５時間耐久後のＮＯｘ吸蔵量を測定したものである。図４によれば、ＮＯｘ吸蔵量は、ＰｄとＰｔが併用された場合に高くなる。したがって、ＰｔとＰｄを高濃度担持した上流部は、ＮＯｘの吸蔵性能に優れる。 FIG. 4 is a graph showing the NOx occlusion amount of pellets in which noble metals (Pd, Pt) are supported on alumina (MI200). Each pellet was prepared so that the supported amounts of Pt and Pd were Pt / Pd = 2/0, 0/5, and 1/2 (weight ratio), respectively, and each pellet was 750 ° C. for 5 hours in an electric furnace. The NOx occlusion amount after endurance is measured. According to FIG. 4, the NOx occlusion amount increases when Pd and Pt are used in combination. Therefore, the upstream portion carrying high concentrations of Pt and Pd is excellent in NOx storage performance.
ＰｔおよびＰｄは、担体基材の下流部よりも上流部で高濃度となるように担持されていればよく、上流部において他の貴金属成分（Ｒｈ等）よりも高濃度で担持されていればよい。したがって、ＰｔおよびＰｄとＲｈとを併用してもよい。 Pt and Pd are only required to be supported at a higher concentration in the upstream portion than the downstream portion of the carrier substrate, and are supported at a higher concentration than other noble metal components (Rh and the like) in the upstream portion. Good. Therefore, Pt and Pd may be used in combination with Rh.
そして、Ｐｔ、ＰｄおよびＲｈのそれぞれの担持量は、性能上、０．１〜５ｇ／Ｌであるのが好ましい。また、Ｐｔ、ＰｄおよびＲｈを触媒担持層に担持する場合は、各種貴金属塩を使用する従来の方法を用いて担持すればよい。 And each load of Pt, Pd and Rh is preferably 0.1 to 5 g / L in view of performance. Further, when Pt, Pd, and Rh are supported on the catalyst support layer, they may be supported using conventional methods using various noble metal salts.
また、ＮＯｘ吸蔵材は、担体基材の上流部で高濃度担持されているのが好ましい。ＮＯｘ吸蔵材を、下流部よりも上流部に高濃度担持することにより、上流部でＮＯｘの吸蔵を主体的に行わせ、上流部から放出されるＮＯｘを下流部で効率よく浄化することができる。 The NOx occlusion material is preferably supported at a high concentration in the upstream portion of the carrier base material. By carrying the NOx occlusion material at a higher concentration in the upstream portion than in the downstream portion, NOx occlusion can be performed mainly in the upstream portion, and NOx released from the upstream portion can be efficiently purified in the downstream portion. .
また、担体基材の上流部の容量は、担体基材の下流部の容量以上であるのが好ましい。上流部の容量が大きいと、上流部でＮＯｘを十分に吸蔵することができるので、効率よくＮＯｘを浄化することができる。たとえば、上流部の容量：下流部の容量＝１：１〜１．５：０．５であれば、ＮＯｘの排出を効果的に抑制することができる。 Moreover, it is preferable that the capacity | capacitance of the upstream part of a support base material is more than the capacity | capacitance of the downstream part of a support base material. If the capacity of the upstream portion is large, NOx can be sufficiently occluded in the upstream portion, so that NOx can be efficiently purified. For example, if the upstream capacity: downstream capacity = 1: 1 to 1.5: 0.5, NOx emissions can be effectively suppressed.
なお、本発明の排ガス浄化触媒は、上記の実施の形態に限定されるものではない。たとえば、本発明の排ガス浄化触媒の効果を損なわない程度であれば、他の機能を追加するために必要に応じて別の物質を添加してもよい。 The exhaust gas purifying catalyst of the present invention is not limited to the above embodiment. For example, as long as the effect of the exhaust gas purification catalyst of the present invention is not impaired, another substance may be added as necessary to add other functions.
以下、本発明の排ガス浄化触媒の実施例を比較例とともに具体的に説明する。 Examples of the exhaust gas purifying catalyst of the present invention will be specifically described below together with comparative examples.
［実施例１］
担体基材として、セル密度４００ｃｐｓｉ、壁厚１５０μｍ、直径１２９ｍｍ、長さ７５ｍｍのコージェライト製ハニカム担体基材（１リットル）を準備した。
[Example 1]
A cordierite honeycomb carrier substrate (1 liter) having a cell density of 400 cpsi, a wall thickness of 150 μm, a diameter of 129 mm, and a length of 75 mm was prepared as a carrier substrate.
アルミナと、チタニア−ジルコニアと、ジルコニアと、ＯＳＣ材と、を所定量の純水と混合し、ミリングしてスラリーＳ1 を調製した。また、アルミナと、チタニア−ジルコニアと、Ｒｈを担持したジルコニアと、ＯＳＣ材と、を所定量の純水と混合し、ミリングしてスラリーＳ2 を調製した。 Alumina, titania - and zirconia, mixed with zirconia, and the OSC material, and pure water a predetermined amount, the slurry S 1 was prepared by milling. Moreover, alumina, titania - mixed with zirconia, and zirconia carrying Rh, and the OSC material, and pure water a predetermined amount, was milled to prepare a slurry S 2.
次に、担体基材にスラリーＳ1 をウォッシュコートし、２５０℃で乾燥後５００℃で１時間焼成し、触媒担持層を形成した。なお、触媒担持層のコート量は、２７０ｇ／Ｌ（アルミナ１００ｇ／Ｌ、チタニア−ジルコニア１００ｇ／Ｌ、ジルコニア５０ｇ／Ｌ、ＯＳＣ材２０ｇ／Ｌ）であった。そして、Ｐｔが２ｇ／Ｌ、Ｐｄが４ｇ／Ｌの担持量となるように調製したジニトロジアンミン白金溶液と硝酸パラジウム水溶液に触媒担持層が形成された担体基材を浸漬して、ＰｔおよびＰｄを吸着担持させ、水溶液から引き上げて、２５０℃で乾燥後５００℃で１時間焼成し、Ｐｔ、Ｐｄを担持した。さらに、Ｂａが０．３ｍｏｌ／Ｌ、Ｋが０．２２５ｍｏｌ／Ｌ、Ｌｉが０．１５ｍｏｌ／Ｌの担持量となるように調製した硝酸バリウム水溶液、硝酸カリウム水溶液および硝酸リチウム水溶液に担体基材を浸漬して、Ｂａ、ＫおよびＬｉを吸着担持させ、水溶液から引き上げて、マイクロウェーブ乾燥を経て、２５０℃で乾燥後５００℃で１時間焼成し、ＮＯｘ吸蔵材（担持量０．６７５ｍｏｌ／Ｌ）を担持した。得られた排ガス浄化触媒を、上流部触媒とする。 Then, the slurry S 1 was wash-coated on a carrier base, and baked for 1 hour after drying 500 ° C. at 250 ° C., to form a catalyst supporting layer. The coating amount of the catalyst support layer was 270 g / L (alumina 100 g / L, titania-zirconia 100 g / L, zirconia 50 g / L, OSC material 20 g / L). Then, a support base material having a catalyst support layer formed in a dinitrodiammine platinum solution and a palladium nitrate aqueous solution prepared so as to have a support amount of Pt of 2 g / L and Pd of 4 g / L is immersed in Pt and Pd. It was adsorbed and supported, pulled up from the aqueous solution, dried at 250 ° C., and calcined at 500 ° C. for 1 hour to carry Pt and Pd. Further, the carrier substrate is immersed in an aqueous solution of barium nitrate, potassium nitrate and lithium nitrate prepared so that the supported amount is Ba 0.3 mol / L, K 0.225 mol / L and Li 0.15 mol / L. Then, Ba, K and Li are adsorbed and supported, pulled up from the aqueous solution, subjected to microwave drying, dried at 250 ° C., and then baked at 500 ° C. for 1 hour, and the NOx occlusion material (supported amount 0.675 mol / L) Supported. Let the obtained exhaust gas purification catalyst be an upstream catalyst.
また、別の担体基材にスラリーＳ2 をウォッシュコートし、２５０℃で乾燥後５００℃で１時間焼成し、触媒担持層を形成した。なお、触媒担持層のコート量は、２７０ｇ／Ｌ（アルミナ１００ｇ／Ｌ、チタニア−ジルコニア１００ｇ／Ｌ、Ｒｈを担持したジルコニア５０ｇ／Ｌ、ＯＳＣ材２０ｇ／Ｌ）、Ｒｈの担持量は、１ｇ／Ｌであった。次に、Ｂａが０．１ｍｏｌ／Ｌ、Ｋが０．０．０７５ｍｏｌ／Ｌ、Ｌｉが０．０５ｍｏｌ／Ｌの担持量となるように調製した硝酸バリウム水溶液、硝酸カリウム水溶液および硝酸リチウム水溶液に担体基材を浸漬して、Ｂａ、ＫおよびＬｉを吸着担持させ、水溶液から引き上げて、マイクロウェーブ乾燥を経て、２５０℃で乾燥後５００℃で１時間焼成し、ＮＯｘ吸蔵材（担持量０．２２５ｍｏｌ／Ｌ）を担持した。得られた排ガス浄化触媒を、下流部触媒とする。 Further, the slurry S 2 was wash-coated on another carrier substrate, dried at 250 ° C. and then fired at 500 ° C. for 1 hour to form a catalyst support layer. The coating amount of the catalyst supporting layer is 270 g / L (alumina 100 g / L, titania-zirconia 100 g / L, zirconia 50 g / L supporting Rh, OSC material 20 g / L), and the supporting amount of Rh is 1 g / L. L. Next, a carrier group was added to a barium nitrate aqueous solution, a potassium nitrate aqueous solution, and a lithium nitrate aqueous solution prepared so as to have a supported amount of Ba of 0.1 mol / L, K of 0.00.075 mol / L, and Li of 0.05 mol / L. The material is immersed to adsorb and support Ba, K, and Li, pulled up from the aqueous solution, subjected to microwave drying, dried at 250 ° C., and calcined at 500 ° C. for 1 hour. L) was supported. Let the obtained exhaust gas purification catalyst be a downstream catalyst.
そして、排ガス流の上流側から下流側にかけて、上流部触媒、下流部触媒、となるように２〜３ｍｍの間隔を開けて順に並べたものを実施例１の排ガス浄化触媒とした。 Then, the exhaust gas purification catalyst of Example 1 was arranged in order from the upstream side to the downstream side of the exhaust gas flow with an interval of 2 to 3 mm so as to become an upstream catalyst and a downstream catalyst.
［比較例１］
担体基材として、セル密度４００ｃｐｓｉ、壁厚１５０μｍ、直径１２９ｍｍ、長さ１５０ｍｍのコージェライト製ハニカム担体基材（２リットル）を準備した。
[Comparative Example 1]
A cordierite honeycomb carrier substrate (2 liters) having a cell density of 400 cpsi, a wall thickness of 150 μm, a diameter of 129 mm, and a length of 150 mm was prepared as a carrier substrate.
担体基材にスラリーＳ2 をウォッシュコートし、２５０℃で乾燥後５００℃で１時間焼成し、触媒担持層（コート量２７０ｇ／Ｌ）を形成した。この際、Ｒｈの担持量は、０．５ｇ／Ｌであった。 Slurry S 2 was wash-coated on the support substrate, dried at 250 ° C. and then calcined at 500 ° C. for 1 hour to form a catalyst supporting layer (coat amount 270 g / L). At this time, the loading amount of Rh was 0.5 g / L.
そして、Ｐｔが２ｇ／Ｌの担持量となるように調製したジニトロジアンミン白金溶液に触媒担持層が形成された担体基材を浸漬して、Ｐｔを吸着担持させ、水溶液から引き上げて、２５０℃で乾燥後５００℃で１時間焼成し、Ｐｔを担持した。さらに、Ｂａが０．２ｍｏｌ／Ｌ、Ｋが０．１５ｍｏｌ／Ｌ、Ｌｉが０．１ｍｏｌ／Ｌの担持量となるように調製した硝酸バリウム水溶液、硝酸カリウム水溶液および硝酸リチウム水溶液に担体基材を浸漬して、Ｂａ、ＫおよびＬｉを吸着担持させ、水溶液から引き上げて、マイクロウェーブ乾燥を経て、２５０℃で乾燥後５００℃で１時間焼成し、ＮＯｘ吸蔵材（担持量０．４５ｍｏｌ／Ｌ）を担持した。 Then, the support base material on which the catalyst support layer is formed is immersed in a dinitrodiammine platinum solution prepared so that the support amount of Pt is 2 g / L, and Pt is adsorbed and supported, and is lifted from the aqueous solution at 250 ° C. After drying, it was calcined at 500 ° C. for 1 hour to carry Pt. Further, the carrier substrate is immersed in an aqueous barium nitrate solution, an aqueous potassium nitrate solution and an aqueous lithium nitrate solution prepared to have a supported amount of Ba of 0.2 mol / L, K of 0.15 mol / L, and Li of 0.1 mol / L. Then, Ba, K, and Li are adsorbed and supported, pulled up from the aqueous solution, subjected to microwave drying, dried at 250 ° C. and then fired at 500 ° C. for 1 hour, and the NOx occlusion material (supported amount 0.45 mol / L) Supported.
［比較例２］
上流側触媒の貴金属担持量をＰｔ：４ｇ／Ｌ、Ｐｄ：０ｇ／Ｌに変更した他は、実施例１と同様にして、比較例２の排ガス浄化触媒を得た。
[Comparative Example 2]
An exhaust gas purification catalyst of Comparative Example 2 was obtained in the same manner as in Example 1 except that the amount of noble metal supported on the upstream catalyst was changed to Pt: 4 g / L and Pd: 0 g / L.
実施例１、比較例１および比較例２の排ガス浄化触媒の構成を表１に示す。 Table 1 shows the configurations of the exhaust gas purification catalysts of Example 1, Comparative Example 1 and Comparative Example 2.
［評価］
実施例１、比較例１および比較例２の排ガス浄化触媒について、吸蔵還元反応の実機評価を行った。試験結果を図１および図２に示す。なお、図１は、各排ガス浄化触媒のＮＯｘ吸蔵プロファイルを示すグラフであって、経過時間（試験時間）に対する各触媒から排出される排出ガスに含まれるＮＯｘの濃度を示す。また、図２は、各排ガス浄化触媒のＮＯｘ浄化性能を示すグラフである。
[Evaluation]
The exhaust gas purification catalysts of Example 1, Comparative Example 1 and Comparative Example 2 were subjected to actual evaluation of the occlusion reduction reaction. The test results are shown in FIG. 1 and FIG. FIG. 1 is a graph showing the NOx occlusion profile of each exhaust gas purification catalyst, and shows the concentration of NOx contained in the exhaust gas discharged from each catalyst with respect to the elapsed time (test time). FIG. 2 is a graph showing the NOx purification performance of each exhaust gas purification catalyst.
各評価試験は、実車８０，０００ｋｍ相当の台上耐久後の排ガス浄化触媒に対して行った。耐久後の評価には、２，０００ｃｃのエンジン（１ＡＺ−ＦＳＥ）を用い、回転数；１６００〜２４００ｒｐｍ、トルク；４．７〜８．２ｋｇｍの条件のもとで評価を行った。また、ＮＯｘ吸蔵プロファイル（図１）では、触媒温度を３００〜５００℃とした。 Each evaluation test was performed on the exhaust gas purification catalyst after the on-board durability corresponding to an actual vehicle of 80,000 km. For the evaluation after endurance, a 2,000 cc engine (1AZ-FSE) was used, and the evaluation was performed under the conditions of the rotational speed: 1600 to 2400 rpm and the torque: 4.7 to 8.2 kgm. In the NOx occlusion profile (FIG. 1), the catalyst temperature was 300 to 500 ° C.
図２によれば、実施例１および比較例２では、ＮＯｘ還元活性の高いＲｈを担体基材の下流部で高濃度となるように担持しているので、上流部で浄化しきれなかったＮＯｘを下流部で効率よく還元できるため、ＮＯｘ浄化率が高い。また、実施例１の排ガス浄化触媒は、ＰｔおよびＰｄが上流部に担持されているため、Ｐｔのシンタリングが抑制される。その結果、ＮＯｘの吸蔵量が増大し、効率よくＮＯｘを浄化することができる。 According to FIG. 2, in Example 1 and Comparative Example 2, since Rh having a high NOx reduction activity is supported at a high concentration in the downstream portion of the carrier substrate, NOx that could not be purified in the upstream portion. Can be efficiently reduced in the downstream portion, so the NOx purification rate is high. Further, in the exhaust gas purifying catalyst of Example 1, Pt and Pd are supported on the upstream portion, so that sintering of Pt is suppressed. As a result, the storage amount of NOx increases and NOx can be purified efficiently.
そして、図１によれば、実施例１の排ガス浄化触媒は、リーン雰囲気でのＮＯｘ吸蔵性能が高いため、排出されるＮＯｘ濃度は低減される。リーン雰囲気で吸蔵された多くのＮＯｘは、リッチスパイク時に気相へ放出されるが、多くのＮＯｘが放出されても、Ｒｈが高濃度で担持された下流部で効率よく還元されるため、リッチスパイク時のＮＯｘの排出は抑制される。また、実施例１の排ガス浄化触媒では、試験開始からの積算量としてのＮＯｘ排出量も低減されている。 And according to FIG. 1, since the exhaust gas purification catalyst of Example 1 has high NOx occlusion performance in a lean atmosphere, the concentration of exhausted NOx is reduced. A lot of NOx occluded in the lean atmosphere is released to the gas phase during the rich spike, but even if a lot of NOx is released, Rh is efficiently reduced in the downstream portion where the high concentration is supported. NOx emissions during spikes are suppressed. Further, in the exhaust gas purification catalyst of Example 1, the NOx emission amount as the integrated amount from the start of the test is also reduced.
Claims (4)
排ガス流の上流側から下流側にかけて配置された上流部触媒と下流部触媒とを備え、
前記上流部触媒はＰｔ、ＰｄおよびＮＯｘ吸蔵材を含み、
前記下流部触媒はＰｔおよびＰｄを含まずＲｈおよびＮＯｘ吸蔵材を含み、Ｒｈは前記上流部触媒よりも該下流部触媒に高濃度担持されていることを特徴とする排ガス浄化触媒。 An exhaust gas purification catalyst having a support substrate, a catalyst support layer formed on the support substrate, and a Pt, Pd, Rh, and NOx storage material supported on the catalyst support layer,
An upstream catalyst and a downstream catalyst arranged from the upstream side to the downstream side of the exhaust gas flow,
The upstream catalyst includes Pt, Pd, and NOx storage material,
Said downstream portion catalyst comprises a Rh and NOx-absorbing material does not contain Pt and Pd, Rh exhaust gas purifying catalyst, characterized in that it is a high concentration carried to the downstream portion catalyst than the upstream portion catalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005049740A JP4923412B2 (en) | 2005-02-24 | 2005-02-24 | Exhaust gas purification catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005049740A JP4923412B2 (en) | 2005-02-24 | 2005-02-24 | Exhaust gas purification catalyst |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2006231204A JP2006231204A (en) | 2006-09-07 |
| JP4923412B2 true JP4923412B2 (en) | 2012-04-25 |
Family
ID=37039431
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005049740A Expired - Fee Related JP4923412B2 (en) | 2005-02-24 | 2005-02-24 | Exhaust gas purification catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4923412B2 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4935219B2 (en) | 2006-07-20 | 2012-05-23 | トヨタ自動車株式会社 | Exhaust gas purification catalyst |
| JP2009248057A (en) * | 2008-04-10 | 2009-10-29 | Toyota Motor Corp | Catalyst for exhaust gas purification |
| JP2010179200A (en) * | 2009-02-03 | 2010-08-19 | Toyota Motor Corp | Catalyst for cleaning exhaust gas |
| JP6222069B2 (en) * | 2014-12-17 | 2017-11-01 | トヨタ自動車株式会社 | Exhaust gas purification catalyst |
| CN111741813B (en) * | 2018-02-21 | 2023-08-04 | 株式会社科特拉 | Exhaust gas purifying catalyst device |
| EP3915680A4 (en) | 2019-01-22 | 2022-03-09 | Mitsui Mining & Smelting Co., Ltd. | Catalyst for purifying exhaust gas |
| JP2020179348A (en) | 2019-04-25 | 2020-11-05 | トヨタ自動車株式会社 | Exhaust gas purifying catalyst |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05293376A (en) * | 1992-04-15 | 1993-11-09 | Nissan Motor Co Ltd | Catalyst for purifying exhaust gas and method therefor |
| JP2002331240A (en) * | 2000-09-05 | 2002-11-19 | Toyota Motor Corp | Exhaust gas cleaning catalyst and exhaust gas cleaning apparatus |
| JP2003343252A (en) * | 2002-05-30 | 2003-12-03 | Nissan Motor Co Ltd | Exhaust gas purifying system |
| JP2004016931A (en) * | 2002-06-17 | 2004-01-22 | Nissan Motor Co Ltd | Exhaust gas purification catalyst |
| JP2004124859A (en) * | 2002-10-04 | 2004-04-22 | Nissan Motor Co Ltd | Exhaust emission control system |
-
2005
- 2005-02-24 JP JP2005049740A patent/JP4923412B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2006231204A (en) | 2006-09-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5807782B2 (en) | Exhaust gas purification catalyst | |
| JP4838258B2 (en) | Exhaust gas purification catalyst | |
| JP4642978B2 (en) | Exhaust gas purification catalyst | |
| US20080045404A1 (en) | Catalyst containing little or no rhodium for purifying exhaust gases of internal combustion engine | |
| EP1188908B1 (en) | Exhaust gas purifying system | |
| JP4923412B2 (en) | Exhaust gas purification catalyst | |
| JP3952617B2 (en) | Exhaust gas purification device, exhaust gas purification method and exhaust gas purification catalyst for internal combustion engine | |
| JP2003340291A (en) | Exhaust gas cleaning catalyst | |
| JP4776151B2 (en) | Exhaust gas purification system | |
| JP3965676B2 (en) | Exhaust gas purification catalyst and exhaust gas purification system | |
| JP4716087B2 (en) | Exhaust gas purification catalyst | |
| JP3704701B2 (en) | Exhaust gas purification catalyst | |
| JP4573993B2 (en) | Exhaust gas purification catalyst and method for producing the same | |
| JP3789231B2 (en) | Exhaust gas purification catalyst | |
| JP4450984B2 (en) | Exhaust gas purification catalyst | |
| JP3985054B2 (en) | Exhaust gas purification catalyst | |
| JP2004275814A (en) | Exhaust gas purifying catalyst, its manufacturing method and exhaust gas purifying apparatus | |
| JPH09253454A (en) | Catalyst for purifying exhaust gas | |
| JP5328133B2 (en) | Exhaust gas purification catalyst | |
| JP4222064B2 (en) | Exhaust gas purification catalyst | |
| JP7288331B2 (en) | Exhaust gas purification catalyst device | |
| JP4507446B2 (en) | Exhaust gas purification catalyst | |
| JP3965793B2 (en) | Exhaust gas purification device, exhaust gas purification method and exhaust gas purification catalyst for internal combustion engine | |
| JP3622893B2 (en) | NOx absorbent and exhaust gas purification catalyst using the same | |
| JP2001162166A (en) | Catalyst for purification of discharged gas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20080123 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20100226 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110201 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110404 |
|
| 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: 20120110 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20120123 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150217 Year of fee payment: 3 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150217 Year of fee payment: 3 |
|
| LAPS | Cancellation because of no payment of annual fees |