JPH11276907A - Catalyst for purifying exhaust gas and its production - Google Patents
Catalyst for purifying exhaust gas and its productionInfo
- Publication number
- JPH11276907A JPH11276907A JP10099942A JP9994298A JPH11276907A JP H11276907 A JPH11276907 A JP H11276907A JP 10099942 A JP10099942 A JP 10099942A JP 9994298 A JP9994298 A JP 9994298A JP H11276907 A JPH11276907 A JP H11276907A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- honeycomb
- exhaust gas
- zeolite
- platinum
- 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.)
- Pending
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 169
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 92
- 239000010410 layer Substances 0.000 claims abstract description 83
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims abstract description 56
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 46
- 239000002344 surface layer Substances 0.000 claims abstract description 42
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 28
- 229910052788 barium Inorganic materials 0.000 claims abstract description 21
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000010949 copper Substances 0.000 claims abstract description 14
- 239000010948 rhodium Substances 0.000 claims abstract description 9
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 8
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims abstract description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 7
- 239000010941 cobalt Substances 0.000 claims abstract description 7
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910052802 copper Inorganic materials 0.000 claims abstract description 7
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims description 66
- 229910021536 Zeolite Inorganic materials 0.000 claims description 64
- 239000010457 zeolite Substances 0.000 claims description 64
- 229910010272 inorganic material Inorganic materials 0.000 claims description 24
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 23
- 150000002484 inorganic compounds Chemical class 0.000 claims description 23
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 16
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 11
- 238000001035 drying Methods 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 8
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 4
- 238000009826 distribution Methods 0.000 abstract description 18
- 238000010030 laminating Methods 0.000 abstract 1
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 102
- 239000007789 gas Substances 0.000 description 45
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 38
- 239000000843 powder Substances 0.000 description 32
- 230000015572 biosynthetic process Effects 0.000 description 25
- 229910000510 noble metal Inorganic materials 0.000 description 23
- 229910004298 SiO 2 Inorganic materials 0.000 description 22
- 239000007864 aqueous solution Substances 0.000 description 17
- 239000011248 coating agent Substances 0.000 description 17
- 238000000576 coating method Methods 0.000 description 17
- 238000000746 purification Methods 0.000 description 16
- 239000000243 solution Substances 0.000 description 13
- 239000000446 fuel Substances 0.000 description 12
- 239000002002 slurry Substances 0.000 description 12
- 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 9
- 230000000052 comparative effect Effects 0.000 description 8
- 229910052680 mordenite Inorganic materials 0.000 description 7
- 229910010413 TiO 2 Inorganic materials 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
- 239000003638 chemical reducing agent Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 229910052878 cordierite Inorganic materials 0.000 description 5
- 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 5
- 239000000203 mixture Substances 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000004453 electron probe microanalysis Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000011812 mixed powder Substances 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 2
- UPIXZLGONUBZLK-UHFFFAOYSA-N platinum Chemical compound [Pt].[Pt] UPIXZLGONUBZLK-UHFFFAOYSA-N 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 230000010718 Oxidation Activity Effects 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- -1 Y-type Chemical compound 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide 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
- 230000008859 change Effects 0.000 description 1
- 229940011182 cobalt acetate Drugs 0.000 description 1
- QAHREYKOYSIQPH-UHFFFAOYSA-L cobalt(II) acetate Chemical compound [Co+2].CC([O-])=O.CC([O-])=O QAHREYKOYSIQPH-UHFFFAOYSA-L 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical compound [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000006193 liquid solution Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、内燃機関、燃焼器
等から排出される排気ガスを浄化する触媒に係り、特に
酸素を過剰に含むディーゼルエンジン排気ガス中の窒素
酸化物を高効率で浄化する排気ガス浄化用触媒及びその
製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for purifying exhaust gas discharged from an internal combustion engine, a combustor, and the like, and more particularly, to purifying nitrogen oxides in a diesel engine exhaust gas containing excess oxygen with high efficiency. The present invention relates to an exhaust gas purifying catalyst and a method for producing the same.
【０００２】[0002]
【従来の技術】従来のガソリンエンジン自動車の排気ガ
スのように、酸化成分と還元成分をほぼ等しく含む排気
ガスを浄化するための触媒としては、３元触媒が広く用
いられる。３元触媒は、白金、パラジウム、ロジウム等
の貴金属及びセリア（Ｃｅ）をはじめとする各種成分を
担持した活性アルミナを主成分とする触媒であり、排気
ガス中の有害成分である炭化水素類（ＨＣ）、一酸化炭
素（ＣＯ）及び窒素酸化物（ＮＯｘ）を高効率で浄化す
ることができる。2. Description of the Related Art A three-way catalyst is widely used as a catalyst for purifying an exhaust gas containing an oxidizing component and a reducing component substantially equally, such as the exhaust gas of a conventional gasoline engine automobile. The three-way catalyst is a catalyst mainly composed of activated alumina carrying various components such as noble metals such as platinum, palladium and rhodium and ceria (Ce), and hydrocarbons (harmful components in exhaust gas). HC), carbon monoxide (CO) and nitrogen oxides (NOx) can be purified with high efficiency.
【０００３】一方、近年、燃費の向上や二酸化炭素の排
出量の削減の観点から、理論空燃比より高い空燃比で運
転するリーンバーンエンジンが注目され、理論空燃比よ
り高い高い空燃比で運転できるディーゼルエンジンも、
燃費の良さが見直されている。しかし、リーンバーンエ
ンジンやディーゼルエンジンの排気ガスは、酸素含有率
が高いため、上記３元触媒ではＮＯｘの浄化が不十分と
なる。また、これらの排気ガスは、排気ガスの温度が低
く、ＮＯｘを浄化するためのＨＣが少ない等の排気ガス
の浄化に不利な条件を備えているが、このような悪条件
の下でも、高効率でＮＯｘを浄化することができる新触
媒が望まれていた。On the other hand, in recent years, attention has been paid to a lean burn engine that operates at an air-fuel ratio higher than the stoichiometric air-fuel ratio from the viewpoints of improving fuel efficiency and reducing carbon dioxide emissions, and can operate at a higher air-fuel ratio than the stoichiometric air-fuel ratio. Diesel engines,
The fuel economy is being reviewed. However, since the exhaust gas of a lean burn engine or a diesel engine has a high oxygen content, the three-way catalyst does not sufficiently purify NOx. In addition, these exhaust gases have disadvantageous conditions for purifying exhaust gas, such as low exhaust gas temperature and low HC for purifying NOx. A new catalyst capable of purifying NOx with high efficiency has been desired.
【０００４】このような状況下において、各種の金属成
分をＹ型、Ｌ型、モルデナイト、ＭＦＩゼオライト等の
ゼオライトに担持したゼオライト系触媒は、リーン排気
ガス中のＨＣの共存下で、ＮＯｘを比較的効率良く浄化
できる能力を有している。かかる金属成分としては、銅
（Ｃｕ）、コバルト（Ｃｏ）、銀（Ａｇ）、ニッケル
（Ｎｉ）、鉄（Ｆｅ）等の遷移金属成分が挙げられ、貴
金属成分では白金（白金）も有効であることが認められ
ているが、中でもＣｕを担持したＣｕ−ゼオライト系触
媒は、高流速ガス条件下であっても比較的優れたＮＯｘ
浄化能を示すため、自動車のような小型移動発生源や定
置型の自家発電用エンジン等の排気ガス浄化への適用に
期待が掛けられていた。Under these circumstances, a zeolite-based catalyst in which various metal components are supported on a zeolite such as Y-type, L-type, mordenite, MFI zeolite, etc., compares NOx in the presence of HC in lean exhaust gas. It has the ability to purify efficiently and efficiently. Examples of such a metal component include transition metal components such as copper (Cu), cobalt (Co), silver (Ag), nickel (Ni), and iron (Fe), and platinum (platinum) is also effective as a noble metal component. Among them, Cu-supported Cu-zeolite-based catalysts have a relatively excellent NOx even under high flow rate gas conditions.
In order to demonstrate the purification ability, application to exhaust gas purification of small mobile sources such as automobiles and stationary type self-powered engines has been expected.
【０００５】ところが、上記金属成分を担持したゼオラ
イト系触媒には、ＮＯｘを比較的効率良く浄化できる温
度範囲が狭く、特に１５０〜３００℃の比較的低い温度
領域では十分なＮＯｘ浄化能力を得ることができないこ
と、また排気ガス中に炭化水素が比較的少ない、特にＨ
Ｃ／ＮＯｘ比が５以下となる条件では、ＮＯｘ浄化能力
が急激に低下すること、更に水蒸気を含む高温（６００
℃以上）の条件（水熱条件）下で極めて劣化が大きいこ
と等の種々の問題点があるため、リーンバーンエンジン
の排気ガス浄化用触媒としては実用化に至っていない。However, the zeolite-based catalyst supporting the above metal component has a narrow temperature range in which NOx can be purified relatively efficiently, and in particular, has a sufficient NOx purification capability in a relatively low temperature range of 150 to 300 ° C. And the exhaust gas contains relatively little hydrocarbons, especially H
Under the condition that the C / NOx ratio is 5 or less, the NOx purification ability is rapidly reduced, and further, the high temperature (600
However, the catalyst has not been put to practical use as a catalyst for purifying exhaust gas of a lean burn engine because of various problems such as extremely large deterioration under the condition (hydrothermal condition).
【０００６】低温度領域でのＮＯｘ浄化能力の向上につ
いては、例えば、Ｃｕ−ゼオライト系触媒層の下層に貴
金属触媒層を設けることにより、貴金属触媒層での反応
熱を利用し、上層のＣｕ−ゼオライト系触媒をより低温
から作動させることが既に提案されている（特開平１−
１２７０４４号、特開平５−６８８８８号）。また、低
ＨＣ／ＮＯｘ比の排気ガス条件では、Ｃｕ−ゼオライト
系触媒や比較的低温でＮＯｘを転化し得る白金系触媒で
あっても、ＮＯｘ浄化能が不十分となるため、ＨＣ、ア
ルコール類等の還元剤の入ったタンクを車載する方法、
燃料自体を還元剤として利用する方法などの触媒の入口
に二次的に還元剤を供給する方法も提案されている。In order to improve the NOx purifying ability in a low temperature region, for example, by providing a noble metal catalyst layer below a Cu-zeolite catalyst layer, the heat of reaction in the noble metal catalyst layer is used to make the upper Cu— It has already been proposed to operate a zeolite-based catalyst from a lower temperature (Japanese Patent Laid-Open Publication No. Hei.
127704, JP-A-5-68888). Further, under exhaust gas conditions with a low HC / NOx ratio, even if a Cu-zeolite-based catalyst or a platinum-based catalyst capable of converting NOx at a relatively low temperature, the NOx purification ability becomes insufficient, so that HC, alcohols, etc. How to mount a tank containing a reducing agent such as
A method of secondary supplying the reducing agent to the inlet of the catalyst, such as a method using the fuel itself as the reducing agent, has also been proposed.
【０００７】[0007]
【発明が解決しようとする課題】しかし、Ｃｕ−ゼオラ
イト系触媒層の下層に貴金属触媒層を設けても、下層の
貴金属触媒層で生じる酸化反応熱のため、劣化が大きく
なったり、貴金属触媒層の強い酸化活性のため、ＨＣが
優先的に酸化消費されることから、ＮＯｘの浄化率が低
下するという課題があった。この影響は、Ｃｕ−ゼオラ
イト系触媒層に貴金属成分を共存させる場合（特開平１
−３１０７４号、特開平５−１６８９３９号）には特に
大きくなる。一方、上述の如く白金系触媒を用いれば、
２００〜２５０℃の比較的低温域でもＮＯｘを転化でき
るが、Ｎ2への転化のみでなく、Ｎ2Ｏの生成も無視する
ことができず、環境への悪影響から、そのままでは使用
できない状況にあるという課題があった。また、還元剤
のタンクを車載する方法は、その収納場所の確保が困難
であり、タンク搭載による重量増や還元剤のインフラの
問題も生じるという課題があった。さらに、燃料を還元
剤として利用する方法では、エンジンの燃費の低下を避
けられないという課題があった。However, even if a noble metal catalyst layer is provided below the Cu-zeolite catalyst layer, the deterioration of the noble metal catalyst layer increases due to the heat of oxidation reaction generated in the lower noble metal catalyst layer. Due to the strong oxidizing activity, HC is preferentially oxidized and consumed, so that there is a problem that the purification rate of NOx decreases. This effect is caused by the presence of a noble metal component in the Cu-zeolite catalyst layer (Japanese Unexamined Patent Publication No.
-31074, JP-A-5-168939). On the other hand, if a platinum-based catalyst is used as described above,
Although NOx can be converted even in a relatively low temperature range of 200 to 250 ° C., not only conversion to N 2 but also generation of N 2 O cannot be neglected. There was a problem that there was. In addition, in the method of mounting a reducing agent tank on a vehicle, it is difficult to secure a storage location, and there is a problem that the mounting of the tank increases the weight and causes a problem of reducing agent infrastructure. Further, the method of using fuel as a reducing agent has a problem that the fuel efficiency of the engine cannot be avoided.
【０００８】本発明は、このような従来技術の有する課
題に鑑みてなされたものであり、その目的とするところ
は、低排気温度及び低ＨＣ／ＮＯｘ比の条件の下で、Ｎ
Ｏｘの浄化性能を向上させた実用レベルの排気ガス浄化
用触媒及びその触媒の製造方法を提供することにある。The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a fuel cell system with a low exhaust temperature and a low HC / NOx ratio.
It is an object of the present invention to provide a practical exhaust gas purifying catalyst having improved Ox purification performance and a method for producing the catalyst.
【０００９】[0009]
【課題を解決するための手段】本発明者らは、上記課題
を解決すべく鋭意検討した結果、ハニカム状モノリス担
体上に積層した触媒層のうち、内層の触媒成分に特定の
分布をもたせること等により、低排気温度及び低ＨＣ／
ＮＯｘ比の条件の下であっても、ＮＯｘの浄化性能が向
上すること等を見出し、本発明を完成するに至った。Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that, among the catalyst layers laminated on the honeycomb-shaped monolithic carrier, a specific distribution is given to the catalyst components in the inner layer. Low exhaust temperature and low HC /
The present inventors have found that the NOx purification performance is improved even under the condition of the NOx ratio, and have completed the present invention.
【００１０】即ち、本発明の排気ガス浄化用触媒は、ハ
ニカム状モノリス担体上に、触媒層たる内層及び表層を
順次積層して成る排気ガス浄化用触媒において、上記内
層が、白金及び／又はパラジウムと、バリウムを含有
し、かつ該白金及び／又はパラジウムの濃度が、上記ハ
ニカム状モノリス担体の壁面に近い程高く、上記表層に
近い程低い分布を成し、上記表層が、銅、ロジウム及び
コバルトから成る群より選ばれた少なくとも１種の成分
を含有することを特徴とする。That is, the exhaust gas purifying catalyst of the present invention is an exhaust gas purifying catalyst comprising a honeycomb monolithic carrier and an inner layer serving as a catalyst layer and a surface layer sequentially laminated thereon, wherein the inner layer is formed of platinum and / or palladium. And the barium-containing and platinum and / or palladium concentration is higher as it is closer to the wall surface of the honeycomb monolithic carrier and lower as it is closer to the surface layer, and the surface layer is made of copper, rhodium and cobalt. Characterized by containing at least one component selected from the group consisting of:
【００１１】本発明の排気ガス浄化用触媒の好適形態
は、上記内層と上記表層との間に、ＭＦＩゼオライト、
モルデナイト、βゼオライト、アルミナ、シリカ、シリ
カ・アルミナ及びチタニアから成る群より選ばれた少な
くとも１種の耐火性無機化合物を含有する中間層を設け
たことを特徴とする。A preferred embodiment of the exhaust gas purifying catalyst according to the present invention is that an MFI zeolite is provided between the inner layer and the surface layer.
An intermediate layer containing at least one refractory inorganic compound selected from the group consisting of mordenite, β zeolite, alumina, silica, silica-alumina and titania is provided.
【００１２】本発明の排気ガス浄化用触媒の製造方法
は、上記の排気ガス浄化用触媒を製造するに当たり、
（１）上記ハニカム状モノリス担体に、上記白金及び／
又はパラジウムを含む水溶液を含浸し、（２）（１）工
程によって得られたハニカム状モノリス担体に、上記耐
火性無機化合物を塗布し、（３）（２）工程により耐火
性無機化合物を塗布したハニカム状モノリス担体を乾燥
することにより、上記ハニカム状モノリス担体上に内層
を積層することを特徴とする。In the method for producing an exhaust gas purifying catalyst of the present invention, when producing the above exhaust gas purifying catalyst,
(1) The above-mentioned platinum and / or
Alternatively, the refractory inorganic compound was applied to the honeycomb monolithic carrier obtained in the step (2) (1) by impregnating with an aqueous solution containing palladium, and the refractory inorganic compound was applied in the step (3) (2). By drying the honeycomb monolith carrier, an inner layer is laminated on the honeycomb monolith carrier.
【００１３】[0013]
【作用】通常、白金等のＮＯｘ吸着材とゼオライト系な
どのＮＯｘ還元触媒とを併用した場合、排気ガス温度が
高くなると、白金及び／又はパラジウムの酸化活性が高
まるため、ＮＯｘの還元に必要なＨＣが酸化消費されて
しまい、十分にＮＯｘの浄化をすることができなくな
る。これに対し、本発明の排気ガス浄化用触媒では、後
述の分布構成を採用しているため、表層中の白金及び／
又はパラジウム並びにバリウムの作用により、２００〜
３００℃の比較的低温の排気ガス中でＮＯｘが吸着さ
れ、吸着されたＮＯｘは、排気ガスの温度が上昇すると
触媒から放出され、表層のＮＯｘ還元触媒層でＨＣと反
応して還元処理されるため、ＮＯｘを十分に浄化するこ
とができる。Normally, when a NOx adsorbent such as platinum and a NOx reduction catalyst such as a zeolite are used in combination, if the exhaust gas temperature increases, the oxidation activity of platinum and / or palladium increases, so that it is necessary to reduce NOx. Since HC is oxidized and consumed, it becomes impossible to sufficiently purify NOx. On the other hand, in the exhaust gas purifying catalyst of the present invention, since the distribution configuration described later is adopted, platinum and / or
Or by the action of palladium and barium,
NOx is adsorbed in the exhaust gas at a relatively low temperature of 300 ° C., and the adsorbed NOx is released from the catalyst when the temperature of the exhaust gas rises, and is reduced by reacting with HC in the surface NOx reduction catalyst layer. Therefore, NOx can be sufficiently purified.
【００１４】即ち、本発明の排気ガス浄化用触媒では、
内層中の白金及び／又はパラジウムの濃度をハニカム状
担体のセル内壁面に近い程高く、表層に近い程低くする
ことにより、排気ガス中のＨＣが貴金属触媒に接近する
ことを妨害する構成としたため、高温域でのＨＣの消費
を防止することができ、高いＮＯｘ浄化率を発揮するこ
とができる。一方、ＮＯｘは分子サイズが小さいため、
内層にまで比較的容易に拡散することから、ＮＯｘの吸
着及び脱離特性は、上述のような貴金属触媒の分布には
影響されず、所期の低排温時のＮＯｘ除去性能も低下し
ない。That is, in the exhaust gas purifying catalyst of the present invention,
Because the concentration of platinum and / or palladium in the inner layer is higher as it is closer to the inner wall surface of the cell of the honeycomb-shaped carrier and lower as it is closer to the surface layer, the structure prevents the HC in the exhaust gas from approaching the noble metal catalyst. In addition, it is possible to prevent the consumption of HC in a high temperature range, and to exhibit a high NOx purification rate. On the other hand, NOx has a small molecular size,
Since it diffuses relatively easily to the inner layer, the NOx adsorption and desorption characteristics are not affected by the distribution of the noble metal catalyst as described above, and the NOx removal performance at the expected low exhaust temperature does not decrease.
【００１５】本発明の排気ガス浄化用触媒の内層と表層
の間に、ＭＦＩゼオライト、モルデナイト、βゼオライ
ト、アルミナ、シリカ、シリカ・アルミナ、チタニアか
ら成る群より選ばれた少なくとも１種の耐火性無機化合
物からなる中間層を設けることも可能であり、これによ
り、ＨＣの内層への拡散がさらに抑制されるので、より
一層ＮＯｘ浄化率が高くなる。At least one refractory inorganic material selected from the group consisting of MFI zeolite, mordenite, β zeolite, alumina, silica, silica-alumina, and titania is provided between the inner layer and the surface layer of the exhaust gas purifying catalyst of the present invention. It is also possible to provide an intermediate layer made of a compound, whereby the diffusion of HC into the inner layer is further suppressed, so that the NOx purification rate is further increased.
【００１６】本発明の排気ガス浄化用触媒の製造方法で
は、従来法とは全く反対に、まずハニカム状担体に貴金
属水溶液を含浸させ、貴金属水溶液を含浸したハニカム
状担体に耐火性無機化合物を塗布し、その耐火性無機化
合物を塗布したハニカム状担体を乾燥することから、ハ
ニカム状担体中から耐火性無機化合物中への貴金属の移
動が抑制され、内層における白金及び／又はパラジウム
の濃度が、ハニカム状担体の壁面に近い程高く、表層に
近い程低くなる分布を実現することができる。In the method for manufacturing an exhaust gas purifying catalyst according to the present invention, the honeycomb-shaped carrier is impregnated with a noble metal aqueous solution, and the refractory inorganic compound is applied to the honeycomb-shaped carrier impregnated with the noble metal aqueous solution. Then, since the honeycomb-shaped carrier coated with the refractory inorganic compound is dried, the movement of the noble metal from the honeycomb-shaped carrier to the refractory inorganic compound is suppressed, and the concentration of platinum and / or palladium in the inner layer is reduced. It is possible to realize a distribution in which the distribution becomes higher as it is closer to the wall surface of the carrier and lower as it is closer to the surface layer.
【００１７】[0017]
【発明の実施の形態】以下、本発明の排気ガス浄化用触
媒及びその製造方法について詳細に説明する。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an exhaust gas purifying catalyst and a method for producing the same according to the present invention will be described in detail.
【００１８】本発明の排気ガス浄化用触媒は、ハニカム
状モノリス担体上に、白金及び／又はパラジウム並びに
バリウムを含有する内層を設け、その上に銅、ロジウム
又はコバルト及びこれらの任意の混合物を含有する表層
を設けた触媒であり、内層における白金及び／又はパラ
ジウムの濃度が、ハニカム状担体の壁面に近い程高く、
表層に近い程低い分布を成すものである。In the exhaust gas purifying catalyst of the present invention, an inner layer containing platinum and / or palladium and barium is provided on a honeycomb-shaped monolith carrier, and copper, rhodium or cobalt and an arbitrary mixture thereof are contained thereon. A catalyst provided with a surface layer, wherein the concentration of platinum and / or palladium in the inner layer is higher as it is closer to the wall surface of the honeycomb-shaped carrier,
The distribution is lower as it is closer to the surface.
【００１９】本発明の排気ガス浄化用触媒では、ハニカ
ム形状のモノリス担体を使用する。かかる担体を使用し
て触媒の形状をハニカム状とすることにより、触媒と排
気ガスとの接触面積が大きくなり、圧力損失も抑えられ
るため、振動があり、かつ限られた空間内で多量の排ガ
スを処理することが要求される自動車用触媒として用い
る場合に有利である。このハニカム材料としては、耐熱
性、耐酸化性及び熱衝撃性に優れ、かつ気孔率の高い材
料が好ましく、一般にコージェライト質のものが広く用
いられるが、これに限定されるものではない。In the exhaust gas purifying catalyst of the present invention, a honeycomb-shaped monolith carrier is used. By making the shape of the catalyst honeycomb using such a carrier, the contact area between the catalyst and the exhaust gas is increased, and the pressure loss is suppressed, so that there is vibration and a large amount of exhaust gas in a limited space. This is advantageous when used as a catalyst for automobiles required to be treated. As the honeycomb material, a material having excellent heat resistance, oxidation resistance, and thermal shock resistance and having high porosity is preferable. In general, cordierite is widely used, but is not limited thereto.
【００２０】本発明の排気ガス浄化用触媒に係る内層
は、白金及び／又はパラジウム並びにバリウムを、耐火
性無機化合物に担持して形成される。The inner layer of the exhaust gas purifying catalyst of the present invention is formed by supporting platinum and / or palladium and barium on a refractory inorganic compound.
【００２１】この耐火性無機化合物には、ＭＦＩゼオラ
イト、モルデナイト、βゼオライト、アルミナ、シリ
カ、シリカ・アルミナ及びチタニアがあり、これらは、
単独でも任意の組み合わせでも使用することができる
が、１００ｍ2／ｇ以上の高比表面積、７００℃程度の
高温に長時間曝されても高い比表面積を維持する高耐熱
性を有することが好ましい。The refractory inorganic compounds include MFI zeolite, mordenite, β zeolite, alumina, silica, silica-alumina and titania.
Although they can be used alone or in any combination, they preferably have a high specific surface area of 100 m 2 / g or more and a high heat resistance that maintains a high specific surface area even when exposed to a high temperature of about 700 ° C. for a long time.
【００２２】内層における白金及び／又はパラジウムの
含有量は、ハニカム状モノリス触媒１Ｌ当たり０．１〜
１．２ｇとすることが好ましい。白金及び／又はパラジ
ウムの含有量が０．１ｇ／Ｌ未満では、貴金属の効果が
得られないことがあり、１．２ｇ／Ｌを超えると、白金
及び／又はパラジウムの濃度がハニカム状担体の接触面
に近い程高く、表層に近い程低いという本発明による分
布の効果が得られなくなり、高温域でのＨＣの酸化消費
が抑制できなくなることがあり、好ましくない。内層に
おけるバリウムの含有量は、ハニカム状モノリス触媒１
Ｌ当たり０．０３〜０．３モルとすることが好ましい。
バリウムの含有量が０．０３モル／Ｌより少ないと、貴
金属の酸化力を抑制し、かつＮＯｘ吸着能を増すという
バリウムの効果が得られないことがあるからであり、
０．３モル／Ｌを超えると、貴金属成分の効果が消失し
て、ＮＯｘ吸着の効果が得られなくなることがあるから
である。The content of platinum and / or palladium in the inner layer is from 0.1 to 1 L per 1 L of the honeycomb-shaped monolith catalyst.
It is preferably 1.2 g. If the content of platinum and / or palladium is less than 0.1 g / L, the effect of the noble metal may not be obtained, and if the content exceeds 1.2 g / L, the concentration of platinum and / or palladium may be lower than that of the honeycomb-shaped carrier. The effect of the distribution according to the present invention, that is, higher as the surface is closer to the surface and lower as the surface is closer to the surface, cannot be obtained. The content of barium in the inner layer is determined by the honeycomb monolith catalyst 1
It is preferred to be 0.03-0.3 mol per L.
If the content of barium is less than 0.03 mol / L, the barium effect of suppressing the oxidizing power of the noble metal and increasing the NOx adsorption ability may not be obtained,
If it exceeds 0.3 mol / L, the effect of the noble metal component may be lost and the effect of NOx adsorption may not be obtained.
【００２３】本触媒の表層は、銅、ロジウム又はコバル
ト及びこれらの任意の混合物からなる成分を、耐火性無
機化合物に担持して形成される。The surface layer of the present catalyst is formed by supporting a component comprising copper, rhodium or cobalt and any mixture thereof on a refractory inorganic compound.
【００２４】この耐火性無機化合物には、ＭＦＩゼオラ
イト、モルデナイト、βゼオライト、アルミナ、シリ
カ、シリカ・アルミナ、チタニア及びジルコニアが含ま
れ、これらは、単独でも組み合わせても使用することが
できる。また、この耐火性無機化合物は、上記と同様に
高比表面積、高耐熱性であることが好ましい。The refractory inorganic compounds include MFI zeolite, mordenite, β zeolite, alumina, silica, silica-alumina, titania and zirconia, and these can be used alone or in combination. Further, it is preferable that the refractory inorganic compound has a high specific surface area and a high heat resistance similarly to the above.
【００２５】また上述した内層と表層の間には、ＭＦＩ
ゼオライト、モルデナイト、βゼオライト、アルミナ、
シリカ、シリカ・アルミナ又はチタニア及びこれらの任
意の混合物である耐火性無機化合物を含む中間層を設け
ることが好ましく、より一層ＮＯｘ浄化率を高くするこ
とができる。但し、中間層はあまり厚くしないことがよ
く、中間層が厚くなると、触媒による圧力損失が増加す
ることがある。The MFI is provided between the inner layer and the surface layer.
Zeolite, mordenite, β zeolite, alumina,
It is preferable to provide an intermediate layer containing a refractory inorganic compound which is silica, silica-alumina, titania, or an arbitrary mixture thereof, so that the NOx purification rate can be further increased. However, the intermediate layer should not be too thick, and if the intermediate layer is thick, the pressure loss due to the catalyst may increase.
【００２６】本発明の排気ガス浄化用触媒を製造するに
は、内層における白金及び／又はパラジウムの濃度がハ
ニカム状担体との接触面に近い程高く、表層に近い程低
くなることが必要とされるため、（１）ハニカム状担体
に、白金及び／又はパラジウムを含む水溶液を含浸させ
る工程、（２）白金及び／又はパラジウムを含む水溶液
を含浸させたハニカム状担体に耐火性無機化合物を塗布
する工程、（３）耐火性無機化合物を塗布した後に乾燥
する工程を順次行うことが好ましい。これに対し、ハニ
カム状担体に耐火性無機化合物を塗布して固着させた
後、ハニカム状担体ごと貴金属を含む水溶液に浸漬して
貴金属を耐火性無機化合物に担持する従来一般に行われ
てきた方法では、貴金属は、乾燥工程での水分の移動、
蒸発に伴って、ハニカム状担体との接触面側から表層側
に移動するため、ハニカム状担体との接触面側の貴金属
成分の濃度が低くなることがあり、好ましくない。In order to manufacture the exhaust gas purifying catalyst of the present invention, it is necessary that the concentration of platinum and / or palladium in the inner layer is higher as the surface is closer to the surface in contact with the honeycomb-shaped carrier and lower as the surface layer is closer. Therefore, (1) a step of impregnating the honeycomb-shaped carrier with an aqueous solution containing platinum and / or palladium, and (2) applying a refractory inorganic compound to the honeycomb-shaped carrier impregnated with an aqueous solution containing platinum and / or palladium. It is preferable to sequentially perform a step and (3) a step of drying after applying the refractory inorganic compound. On the other hand, after the refractory inorganic compound is applied and fixed on the honeycomb-shaped carrier, the honeycomb carrier is immersed in an aqueous solution containing a noble metal, and the noble metal is supported on the refractory inorganic compound. , Precious metals transfer moisture during the drying process,
As the solvent moves from the contact surface side with the honeycomb-shaped carrier to the surface layer with evaporation, the concentration of the noble metal component on the contact surface side with the honeycomb-shaped carrier may decrease, which is not preferable.
【００２７】なお、ハニカム状担体に白金及び／又はパ
ラジウムを含む貴金属水溶液を含浸させた後には、余分
な溶液を吹き飛ばしたり、適当な乾燥工程を入れたりし
て、液だれが起こらないようにすることが好ましい。ま
た、貴金属水溶液を含浸させたハニカム状担体に耐火性
無機化合物を塗布する際、ハニカム状担体は、適当に湿
潤していることが好ましい。ハニカム状担体を過度に乾
燥させると、乾燥工程において、貴金属がハニカム状担
体中から耐火性無機化合物中へ移動しなくなることがあ
るからである。After the honeycomb-shaped carrier is impregnated with an aqueous solution of a noble metal containing platinum and / or palladium, excess solution is blown off or an appropriate drying step is performed to prevent dripping. Is preferred. Further, when the refractory inorganic compound is applied to the honeycomb-shaped carrier impregnated with the noble metal aqueous solution, it is preferable that the honeycomb-shaped carrier is appropriately moistened. This is because if the honeycomb-shaped carrier is excessively dried, the noble metal may not move from the honeycomb-shaped carrier into the refractory inorganic compound in the drying step.
【００２８】バリウムを内層に含ませる工程は、（１）
〜（３）のいずれの工程中又は工程後であってもよい
が、バリウムも貴金属と同様の分布をもたせることが好
ましく、溶液濃度、ハニカム担体の気孔率等の条件に応
じて、上述の工程の順序を最適化することが好ましい。The step of including barium in the inner layer is as follows:
Although barium may have the same distribution as the noble metal during or after any of the steps (3) to (3), the above-described step may be performed depending on conditions such as the solution concentration and the porosity of the honeycomb carrier. Is preferably optimized.
【００２９】[0029]
【実施例】以下、本発明を実施例及び比較例により更に
詳細に説明するが、本発明はこれら実施例に限定される
ものではない。EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
【００３０】（実施例１） （１）内層の形成 ジニトロジアンミン白金水溶液中に、１平方インチ断面
当たり約４００個の流路を持つコージェライト質ハニカ
ム担体１．０Ｌを浸し、その後引き上げ、余分な溶液を
吹き飛ばした。一方、比表面積が約２８０ｍ2／ｇの活
性Ａｌ2Ｏ3粉末に、アルミナゾル４ｗｔ％及び水を混合
し、磁性ボールミルポットで約１０分間混合、粉砕して
活性Ａｌ2Ｏ3のスラリーを得た。こうして得られた活性
Ａｌ2Ｏ3のスラリーを、ジニトロジアンミン白金水溶液
を含浸したコージェライト質ハニカム担体１．０Ｌに塗
布し、ハニカムセルに１５０℃の熱風を通じて乾燥した
後、５００℃で１時間焼成してコート量約５０ｇ／Ｌの
ハニカム触媒１を得た。次いで、このハニカム触媒１を
酢酸バリウム水溶液に浸した後、１２０℃で乾燥、５０
０℃で１時間焼成し、バリウムをハニカム触媒１Ｌ当た
り０．０６５モルを含有するハニカム触媒体１Ａを得
た。ハニカム触媒体１Ａのコート層における白金の分布
をＥＰＭＡで分析した結果、コート層の上半層部には、
白金は検出されなかったが、下半層部には、０．４ｇ／
Ｌの白金が検出された。ハニカム担体からは、０．１ｇ
／Ｌの白金が検出された。Example 1 (1) Formation of Inner Layer 1.0 L of a cordierite-based honeycomb carrier having about 400 flow channels per square inch cross section was immersed in an aqueous dinitrodiammineplatinum solution, and then pulled up to remove excess The solution was blown off. On the other hand, 4 wt% of alumina sol and water were mixed with active Al 2 O 3 powder having a specific surface area of about 280 m 2 / g, mixed and pulverized in a magnetic ball mill pot for about 10 minutes to obtain a slurry of active Al 2 O 3 . . The thus-obtained slurry of active Al 2 O 3 was applied to 1.0 L of cordierite-based honeycomb carrier impregnated with an aqueous solution of dinitrodiammine platinum, dried in a honeycomb cell through hot air at 150 ° C., and fired at 500 ° C. for 1 hour. Thus, a honeycomb catalyst 1 having a coating amount of about 50 g / L was obtained. Next, this honeycomb catalyst 1 was immersed in an aqueous barium acetate solution, and then dried at 120 ° C.
Calcination was performed at 0 ° C. for 1 hour to obtain a honeycomb catalyst body 1A containing 0.065 mol of barium per liter of the honeycomb catalyst. The distribution of platinum in the coat layer of the honeycomb catalyst body 1A was analyzed by EPMA, and as a result,
No platinum was detected, but 0.4 g /
L platinum was detected. 0.1 g from honeycomb carrier
/ L of platinum was detected.
【００３１】（２）表層の形成 濃度０．２Ｍの酢酸銅水溶液の中に、ＳｉＯ2／Ａｌ2Ｏ
3モル比が、約３０のＮａ型ＭＦＩゼオライトの粉末を
添加して良く撹拌し、次いで濾過して固液を分離した。
上記の攪枠、濾過を５回繰り返し、Ｃｕをイオン交換担
持したＭＦＩゼオライトの触媒ケーキを得た。この触媒
ケーキを乾燥器中、８０℃で２４時間以上乾燥し、次い
で電気炉を用い、大気雰囲気下６００℃で４時間焼成
し、Ｃｕが５．６ｗｔ％担持されたＣｕ−ＭＦＩ触媒粉
を得た。このＣｕ−ＭＦＩ触媒粉に、アルミナゾル及び
水を混合し、磁性ボールミルポットで２０分間粉砕して
Ｃｕ−ＭＦＩのスラリーを得た。アルミナゾルの添加量
は、Ａｌ2Ｏ3として全固形分に対して８ｗｔ％とした。
得られたＣｕ−ＭＦＩのスラリーをハニカム触媒体１Ａ
に塗布し、乾燥器中１２０℃で１時間乾燥、空気気流中
４５０℃で１時間焼成して、実施例１になる触媒を得
た。実施例１の表層におけるコート量は、約２２０ｇ／
Ｌであった。(2) Formation of Surface Layer In a copper acetate aqueous solution having a concentration of 0.2 M, SiO 2 / Al 2 O was added.
3 molar ratio, thoroughly stirred by adding powder of about 30 Na-type MFI zeolite, then filtered to separate the solid-liquid.
The above stirring and filtration were repeated 5 times to obtain a catalyst cake of MFI zeolite carrying Cu ion exchange. The catalyst cake was dried in a dryer at 80 ° C. for 24 hours or more, and then calcined at 600 ° C. for 4 hours in an air atmosphere using an electric furnace to obtain a Cu-MFI catalyst powder carrying 5.6 wt% of Cu. Was. Alumina sol and water were mixed with the Cu-MFI catalyst powder, and pulverized in a magnetic ball mill pot for 20 minutes to obtain a Cu-MFI slurry. The addition amount of the alumina sol was 8 wt% with respect to the total solid content as Al 2 O 3 .
The obtained slurry of Cu-MFI was mixed with the honeycomb catalyst 1A.
And dried in an oven at 120 ° C. for 1 hour, and calcined in an air stream at 450 ° C. for 1 hour to obtain a catalyst of Example 1. The coating amount on the surface layer of Example 1 was about 220 g /
L.
【００３２】（実施例２） （１）内層の形成 ジニトロジアンミン白金水溶液を、硝酸パラジウム水溶
液とし、比表面積が約２８０ｍ2／ｇの活性Ａｌ2Ｏ3粉
末を、比表面積が約４３０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3
モル比が約３４のＨ型ＭＦＩゼオライトに代えた以外
は、実施例１と同様の操作を繰り返し、コート量が約５
０ｇ／Ｌのハニカム触媒体２Ａを得た。ハニカム触媒体
２Ａにおけるバリウムの含有量は、ハニカム１Ｌ当たり
０．０７モル、パラジウムの含有量は、０．６ｇ／Ｌで
あった。ハニカム触媒体２Ａのコート層におけるパラジ
ウムの分布は、実施例１のハニカム触媒体１Ａとほぼ同
様であった。[0032] (Example 2) (1) an inner layer forming dinitrodiammineplatinum solution, and aqueous palladium nitrate solution, the active Al 2 O 3 powder having a specific surface area of about 280 meters 2 / g, a specific surface area of about 430m 2 / g , SiO 2 / Al 2 O 3
The same operation as in Example 1 was repeated except that the H-type MFI zeolite having a molar ratio of about 34 was used.
0 g / L of a honeycomb catalyst body 2A was obtained. The barium content in the honeycomb catalyst body 2A was 0.07 mol per 1 L of the honeycomb, and the palladium content was 0.6 g / L. The distribution of palladium in the coat layer of the honeycomb catalyst 2A was substantially the same as that of the honeycomb catalyst 1A of Example 1.
【００３３】（２）中間層の形成 比表面積が約２８０ｍ2／ｇの活性Ａｌ2Ｏ3粉末に、ア
ルミナゾル４ｗｔ％及び水を混合し、磁性ボールミルポ
ットで約１０分間混合、粉砕して活性Ａｌ2Ｏ3のスラリ
ーを得た。こうして得られたスラリーを、ハニカム触媒
体２Ａに塗布し、ハニカムセルに１５０℃の熱風を通じ
て乾燥した後、５００℃で１時間焼成し、約１５ｇ／Ｌ
のコート層を形成したハニカム触媒体２Ｂを得た。(2) Formation of Intermediate Layer An active Al 2 O 3 powder having a specific surface area of about 280 m 2 / g was mixed with 4 wt% of alumina sol and water, and mixed and pulverized for about 10 minutes in a magnetic ball mill pot to obtain active Al. A slurry of 2 O 3 was obtained. The slurry thus obtained was applied to the honeycomb catalyst body 2A, dried by passing hot air through a honeycomb cell at 150 ° C., and calcined at 500 ° C. for 1 hour to obtain about 15 g / L.
Thus, a honeycomb catalyst body 2B having a coating layer formed thereon was obtained.
【００３４】（３）表層の形成 実施例１と同様の操作を繰り返し、ハニカム触媒体２Ｂ
に、Ｃｕ−ＭＦＩのスラリーを塗布してハニカム触媒体
２Ｃを得た。これとは別に、濃度０．１Ｍの硝酸銅水溶
液の中に、ＳｉＯ2／Ａｌ2Ｏ3モル比が約３５のＮａ型
βゼオライトの粉末を添加して良く撹拌し、次いで濾過
して固液を分離した。上記の撹拌濾過を２回繰り返した
後、水洗を施してＣｕを１．２ｗｔ％担持させたβゼオ
ライトの触媒粉を得た。このようにして得られたＣｕ−
βゼオライトを、実施例１と同様の操作を繰り返し、ハ
ニカム触媒体２Ｃに、塗布、乾燥及び焼成して実施例２
になる触媒を得た。実施例２の表層におけるコート量
は、Ｃｕ−ＭＦＩゼオライトが約１５０ｇ／Ｌ、Ｃｕ−
βゼオライトが約７０ｇ／Ｌであった。(3) Formation of Surface Layer The same operation as in Example 1 was repeated to obtain the honeycomb catalyst 2B.
Was coated with a slurry of Cu-MFI to obtain a honeycomb catalyst body 2C. Separately, a powder of Na-type β zeolite having a SiO 2 / Al 2 O 3 molar ratio of about 35 was added to an aqueous solution of copper nitrate having a concentration of 0.1 M, stirred well, and then filtered to obtain a solid-liquid solution. Was isolated. After repeating the above-mentioned stirring filtration twice, it was washed with water to obtain a β zeolite catalyst powder carrying 1.2 wt% of Cu. The thus obtained Cu-
The same operation as in Example 1 was repeated on β zeolite to apply, dry, and calcine the honeycomb catalyst body 2C to obtain Example 2.
Was obtained. The coating amount in the surface layer of Example 2 was about 150 g / L for Cu-MFI zeolite,
β zeolite was about 70 g / L.
【００３５】（実施例３） （１）内層の形成 比表面積が約２８０ｍ2／ｇの活性Ａｌ2Ｏ3粉末を、比
表面積が約４７０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モル比が
約３８のＨ型βゼオライトに代えた以外は、実施例１と
同様の操作を繰り返し、コート量が約５０ｇ／Ｌのハニ
カム触媒体３Ａを得た。ハニカム触媒体３Ａにおける白
金の含有量は、約０．６ｇ／Ｌであり、バリウムの含有
量は、０．０７モル／Ｌであった。コート層における白
金の分布は、実施例１のハニカム触媒体１Ａとほぼ同様
であった。(Example 3) (1) Formation of inner layer An active Al 2 O 3 powder having a specific surface area of about 280 m 2 / g was prepared, and a specific surface area of about 470 m 2 / g and a SiO 2 / Al 2 O 3 molar ratio were obtained. The same operation as in Example 1 was repeated except that about 38 H-type β zeolite was used, to obtain a honeycomb catalyst body 3A having a coating amount of about 50 g / L. The platinum content in the honeycomb catalyst body 3A was about 0.6 g / L, and the barium content was 0.07 mol / L. The distribution of platinum in the coat layer was almost the same as that of the honeycomb catalyst 1A of Example 1.
【００３６】（２）中間層の形成 比表面積が約２８０ｍ2／ｇの活性Ａｌ2Ｏ3粉末を、比
表面積が約４５０ｍ2／ｇのＳｉＯ2・Ａｌ2Ｏ3粉末に代
えた以外は、実施例２と同様の操作を繰り返し、ハニカ
ム触媒体３Ａに、コート量約１５ｇ／Ｌを形成したハニ
カム触媒体３Ｂを得た。[0036] (2) except that forming specific surface area of the intermediate layer is an active Al 2 O 3 powder of about 280 meters 2 / g, specific surface area instead of the SiO 2 · Al 2 O 3 powder of about 450 m 2 / g is The same operation as in Example 2 was repeated to obtain a honeycomb catalyst body 3B in which a coating amount of about 15 g / L was formed on the honeycomb catalyst body 3A.
【００３７】（３）表層の形成 濃度０．１Ｍの酢酸コバルト水溶液の中に、ＳｉＯ2／
Ａｌ2Ｏ3モル比が約３５のＮａ型βゼオライトの粉末を
添加して良く撹拌し、次いで濾過して固液を分離した。
上記の撹拌濾過を２回繰り返した後、水洗を施してＣｕ
が約２．４ｗｔ％担持されたβゼオライトの触媒粉を得
た。これとは別に、実施例１と同様の操作を繰り返し、
Ｃｕ−ＭＦＩゼオライトの粉末を得た。このようにして
得られたＣｕ−βゼオライトの粉末及びＣｕ−ＭＦＩゼ
オライトの混合粉末を、実施例１と同様の操作を繰り返
し、ハニカム触媒体３Ｂに、塗布、乾燥及び焼成して実
施例３になる触媒を得た。実施例３の表層におけるコー
ト量は、約２２０ｇ／Ｌであり、その内訳は、Ｃｕ−Ｍ
ＦＩゼオライトが約１５０ｇ／Ｌ、Ｃｏ−βゼオライト
が約７０ｇ／Ｌであった。(3) Formation of Surface Layer In an aqueous solution of cobalt acetate having a concentration of 0.1 M, SiO 2 /
A powder of Na-type β zeolite having an Al 2 O 3 molar ratio of about 35 was added, and the mixture was stirred well and then filtered to separate a solid and a liquid.
After repeating the above-mentioned stirring filtration twice, washing with water is performed to remove Cu.
Was carried at about 2.4 wt% to obtain a catalyst powder of β zeolite. Apart from this, the same operation as in Example 1 is repeated,
A powder of Cu-MFI zeolite was obtained. The obtained powder of Cu-β zeolite and mixed powder of Cu-MFI zeolite were coated on the honeycomb catalyst body 3B, dried and calcined by repeating the same operation as in Example 1 to obtain Example 3. Catalyst was obtained. The coating amount in the surface layer of Example 3 was about 220 g / L, and the content was Cu-M
The FI zeolite was about 150 g / L, and the Co-β zeolite was about 70 g / L.
【００３８】（実施例４） （１）内層の形成 ジニトロジアンミン白金水溶液の濃度及び酢酸バリウム
の濃度を変更し、比表面積が約４７０ｍ2／ｇ、ＳｉＯ2
／Ａｌ2Ｏ3モル比が約３８のＨ型βゼオライトを、比表
面積が約３４０ｍ2／ｇ、ＳｉＯ2・Ａｌ2Ｏ3モル比が約
２８のＨ型モルデナイトに代えた以外は、実施例３と同
様の操作を繰り返し、コート量が約５０ｇ／Ｌのハニカ
ム触媒体４Ａを得た。ハニカム触媒体４Ａにおける白金
の含有量は、０．１５ｇ／Ｌ、バリウムの含有量は、
０．０３５モル／Ｌであった。ハニカム触媒体４Ａのコ
ート層における白金の分布は、実施例１のハニカム触媒
体１Ａとほぼ同様であった。[0038] (Example 4) (1) to change the concentration and the concentration of barium acetate inner layer forming dinitrodiammineplatinum aqueous solution, a specific surface area of about 470m 2 / g, SiO 2
Example 1 was repeated except that the H-type β zeolite having a / Al 2 O 3 molar ratio of about 38 was replaced with an H-type mordenite having a specific surface area of about 340 m 2 / g and a SiO 2 · Al 2 O 3 molar ratio of about 28. The same operation as in Example 3 was repeated to obtain a honeycomb catalyst body 4A having a coating amount of about 50 g / L. The platinum content in the honeycomb catalyst body 4A was 0.15 g / L, and the barium content was
It was 0.035 mol / L. The distribution of platinum in the coat layer of the honeycomb catalyst 4A was substantially the same as that of the honeycomb catalyst 1A of Example 1.
【００３９】（２）中間層の形成 比表面積が約４５０ｍ2／ｇのＳｉＯ2・Ａｌ2Ｏ3粉末
を、比表面積が約４７０ｍ2／ｇのＳｉＯ2／Ａｌ2Ｏ3モ
ル比が約３８のＨ型βゼオライトの粉末に代えた以外
は、実施例３と同様の操作を繰り返し、ハニカム触媒体
４Ａに、約２０ｇ／Ｌのコート層を形成したハニカム触
媒体４Ｂを得た。[0039] (2) the SiO 2 · Al 2 O 3 powder of forming specific surface area of the intermediate layer is about 450 m 2 / g, a specific surface area of SiO 2 / Al 2 O 3 molar ratio of about 470m 2 / g of about 38 The same procedure as in Example 3 was repeated, except that the powder was replaced with the H type β zeolite powder, to obtain a honeycomb catalyst body 4B in which a coat layer of about 20 g / L was formed on the honeycomb catalyst body 4A.
【００４０】（３）表層の形成 実施例３と同様の操作を繰り返し、Ｃｕ−βゼオライト
の粉末及びＣｕ−ＭＦＩゼオライトの混合粉末を、ハニ
カム触媒体４Ｂに、塗布、乾燥及び焼成して実施例４に
なる触媒を得た。実施例４の表層におけるコート量は、
約２３０ｇ／Ｌであり、その内訳は、Ｃｕ−ＭＦＩゼオ
ライトが約１５０ｇ／Ｌ、Ｃｏ−βゼオライトが約８０
ｇ／Ｌであった。(3) Formation of Surface Layer The same operation as in Example 3 was repeated, and the powder of Cu-β zeolite and the mixed powder of Cu-MFI zeolite were applied to the honeycomb catalyst body 4B, dried and calcined. 4 was obtained. The coating amount in the surface layer of Example 4 was
About 230 g / L, of which about 150 g / L for Cu-MFI zeolite and about 80 g for Co-β zeolite
g / L.
【００４１】（実施例５） （１）内層の形成 ジニトロジアンミン白金水溶液を、ジニトロジアンミン
白金及び硝酸パラジウムの混合水溶液にし、比表面積が
約２８０ｍ2／ｇの活性Ａｌ2Ｏ3粉末を、比表面積が約
７０ｍ2／ｇのＴｉＯ2粉末及び比表面積が約３５０ｍ2
／ｇのＳｉＯ2粉末の混合粉末に代え、酢酸バリウム水
溶液の濃度を変更した以外は、実施例１と同様の操作を
繰り返し、コート量が約８０ｇ／Ｌのハニカム触媒体５
Ａを得た。ハニカム触媒体５Ａのコート層におけるバリ
ウムの含有量は、０．６モル／Ｌ、白金の含有量は、
０．６ｇ／Ｌ、パラジウムの含有量は、０．５ｇ／Ｌで
あった。ハニカム触媒体５Ａのコート層における白金及
びパラジウムの分布は、実施例１のハニカム触媒体１Ａ
とほぼ同様であった。Example 5 (1) Formation of Inner Layer An aqueous solution of dinitrodiammine platinum was converted into a mixed aqueous solution of dinitrodiammineplatinum and palladium nitrate, and an active Al 2 O 3 powder having a specific surface area of about 280 m 2 / g was prepared. There TiO 2 powder and the specific surface area of about 70m 2 / g is approximately 350 meters 2
/ G of SiO 2 powder, and the same operation as in Example 1 was repeated, except that the concentration of the aqueous barium acetate solution was changed, to obtain a honeycomb catalyst 5 having a coating amount of about 80 g / L.
A was obtained. The barium content in the coat layer of the honeycomb catalyst body 5A was 0.6 mol / L, and the platinum content was
0.6 g / L and the content of palladium were 0.5 g / L. The distribution of platinum and palladium in the coat layer of the honeycomb catalyst body 5A is the same as that of the honeycomb catalyst body 1A of Example 1.
It was almost the same.
【００４２】（２）中間層の形成 比表面積が約２８０ｍ2／ｇの活性Ａｌ2Ｏ3粉末を、比
表面積が約４３０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モル比が
約３４のＨ型ＭＦＩゼオライトに代えた以外は、実施例
２と同様の操作を繰り返し、ハニカム触媒体５Ａに、約
２０ｇ／Ｌのコート層を形成したハニカム触媒体５Ｂを
得た。(2) Formation of Intermediate Layer An active Al 2 O 3 powder having a specific surface area of about 280 m 2 / g was converted into H 2 having a specific surface area of about 430 m 2 / g and a SiO 2 / Al 2 O 3 molar ratio of about 34. The same operation as in Example 2 was repeated except that the type MFI zeolite was used, to obtain a honeycomb catalyst body 5B in which a coat layer of about 20 g / L was formed on the honeycomb catalyst body 5A.
【００４３】（３）表層の形成 硝酸ロジウム水溶液に比表面積が約２８０ｍ2／ｇの活
性Ａｌ2Ｏ3粉末を添加して良く撹拌し、次いで乾燥機で
１２０℃で５時間乾燥した後、５５０℃で４時間焼成す
ることにより、ロジウムが２．２％担持されたＡｌ2Ｏ3
の粉末を得た。このロジウム担持Ａｌ2Ｏ3粉末にアルミ
ナゾル及び水を混合し、磁性ボールミルポットで２０分
間粉砕してＲｈ−Ａｌ2Ｏ3のスラリーを得た。アルミナ
ゾルの添加量は、Ａｌ2Ｏ3として全固形分に対して８ｗ
ｔ％とした。得られたＲｈ−Ａｌ2Ｏ3のスラリーをハニ
カム触媒体５Ｂに塗布してハニカム触媒体５Ｃを得た。
これとは別に、実施例１と同様の操作を繰り返し、Ｃｕ
−ＭＦＩゼオライトのスラリーを得た。得られたＣｕ−
ＭＦＩゼオライトのスラリーを、実施例１と同様の操作
を繰り返し、ハニカム触媒体５Ｃに、塗布、乾燥及び焼
成して実施例５になる触媒を得た。実施例５の表層にお
けるコート量は、Ｒｈ−Ａｌ2Ｏ3が約１００ｇ／Ｌ、Ｃ
ｕ−ＭＦＩゼオライトが約１６０ｇ／Ｌであった。(3) Formation of Surface Layer An active Al 2 O 3 powder having a specific surface area of about 280 m 2 / g was added to an aqueous rhodium nitrate solution, stirred well, dried at 120 ° C. for 5 hours in a drier, and then dried. Baked at 4 ° C. for 4 hours to obtain Al 2 O 3 carrying 2.2% of rhodium.
Was obtained. Alumina sol and water were mixed with this rhodium-supported Al 2 O 3 powder, and ground with a magnetic ball mill pot for 20 minutes to obtain a slurry of Rh—Al 2 O 3 . The addition amount of alumina sol, 8w on the total solid content as Al 2 O 3
t%. The obtained slurry of Rh-Al 2 O 3 was applied to the honeycomb catalyst 5B to obtain a honeycomb catalyst 5C.
Separately, the same operation as in Example 1 was repeated to obtain Cu
-A slurry of MFI zeolite was obtained. The obtained Cu-
The same operation as in Example 1 was repeated with the slurry of the MFI zeolite, applied to the honeycomb catalyst body 5C, dried and calcined to obtain a catalyst of Example 5. The coating amount in the surface layer of Example 5 was about 100 g / L for Rh-Al 2 O 3 ,
The u-MFI zeolite was about 160 g / L.
【００４４】（実施例６） （１）内層の形成 ジニトロジアンミン白金水溶液の濃度及び酢酸バリウム
水溶液濃度を変更した以外は、実施例３と同様の操作を
繰り返し、コート量が約６０ｇ／Ｌのハニカム触媒体６
Ａを得た。ハニカム触媒体６Ａのコート層における白金
の含有量は、０．８ｇ／Ｌ、バリウムの含有量は、０．
１モル／Ｌであった。コート層における白金の分布は、
実施例１のハニカム触媒体１Ａとほぼ同様であった。Example 6 (1) Formation of Inner Layer The same operation as in Example 3 was repeated except that the concentration of the dinitrodiammine platinum aqueous solution and the concentration of the barium acetate aqueous solution were changed, and a honeycomb having a coating amount of about 60 g / L was used. Catalyst 6
A was obtained. The content of platinum in the coat layer of the honeycomb catalyst body 6A was 0.8 g / L, and the content of barium was 0.1 g / L.
It was 1 mol / L. The distribution of platinum in the coat layer is
It was almost the same as the honeycomb catalyst body 1A of Example 1.
【００４５】（２）中間層の形成 比表面積が約４５０ｍ2／ｇのＳｉＯ2・Ａｌ2Ｏ3粉末
を、比表面積が約３４０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モ
ル比が約２８のＨ型モルデナイトに代えた以外は、実施
例３と同様の操作を繰り返し、ハニカム触媒体６Ａに、
約２０ｇ／Ｌのコート層を形成したハニカム触媒体６Ｂ
を得た。(2) Formation of Intermediate Layer An SiO 2 .Al 2 O 3 powder having a specific surface area of about 450 m 2 / g was converted to a powder having a specific surface area of about 340 m 2 / g and a SiO 2 / Al 2 O 3 molar ratio of about 28. The same operation as in Example 3 was repeated except that the H-type mordenite was replaced with a honeycomb catalyst body 6A,
Honeycomb catalyst body 6B having a coating layer of about 20 g / L
I got
【００４６】（３）表層の形成 比表面積が約２８０ｍ2／ｇの活性Ａｌ2Ｏ3粉末を、比
表面積が約４７０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モル比が
約３８のＨ型βゼオライトに代えた以外は、実施例４と
同様の操作を繰り返し、ハニカム触媒体６Ｂに、塗布、
乾燥及び焼成して実施例６になる触媒を得た。ここで、
Ｒｈ−βゼオライトのＲｈ担持量は２．５ｗｔ％であっ
た。実施例６の表層におけるコート量は、Ｒｈ−βゼオ
ライトが約１００ｇ／Ｌ、Ｃｕ−ＭＦＩゼオライトが約
１６０ｇ／Ｌであった。(3) Formation of Surface Layer An active Al 2 O 3 powder having a specific surface area of about 280 m 2 / g was converted to an H type powder having a specific surface area of about 470 m 2 / g and a SiO 2 / Al 2 O 3 molar ratio of about 38. The same operation as in Example 4 was repeated, except that the zeolite was replaced with β zeolite.
Drying and calcining yielded a catalyst of Example 6. here,
The Rh-supporting amount of the Rh-β zeolite was 2.5 wt%. The coating amount in the surface layer of Example 6 was about 100 g / L for Rh-β zeolite and about 160 g / L for Cu-MFI zeolite.
【００４７】（実施例７） （１）内層の形成 実施例６と同様の操作を繰り返し、ハニカム触媒体７Ａ
を得た。Example 7 (1) Formation of Inner Layer The same operation as in Example 6 was repeated to obtain a honeycomb catalyst body 7A.
I got
【００４８】（２）中間層の形成 比表面積が約３４０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モル比
が約２８のＨ型モルデナイトを、比表面積が約７０ｍ2
／ｇのＴｉＯ2に代えた以外は、実施例６と同様の操作
を繰り返し、ハニカム触媒体７Ａに、約２０ｇ／Ｌのコ
ート層を形成したハニカム触媒体７Ｂを得た。[0048] (2) forming specific surface area of the intermediate layer is about 340m 2 / g, the H-type mordenite of SiO 2 / Al 2 O 3 molar ratio of about 28, a specific surface area of about 70m 2
The same operation as in Example 6 was repeated, except that TiO 2 / g of TiO 2 was used, to obtain a honeycomb catalyst body 7B in which a coat layer of about 20 g / L was formed on the honeycomb catalyst body 7A.
【００４９】（３）表層の形成 Ｈ型βゼオライトを、比表面積が約６５ｍ2／ｇのＺｒ
Ｏ2に代えた以外は、実施例６と同様の操作を繰り返
し、ハニカム触媒体７Ｂに、Ｃｕ−ＭＦＩゼオライト及
びＲｈ−ＺｒＯ2を、塗布、乾燥及び焼成して実施例７
になる触媒を得た。実施例７の表層におけるコート量
は、Ｃｕ−ＭＦＩゼオライトが約１６０ｇ／Ｌ、Ｒｈ−
ＺｒＯ2が約１００ｇ／Ｌであった。(3) Formation of Surface Layer H-type zeolite was converted to Zr having a specific surface area of about 65 m 2 / g.
The same operation as in Example 6 was repeated, except that O 2 was used, and Cu-MFI zeolite and Rh-ZrO 2 were coated, dried and calcined on the honeycomb catalyst body 7B to obtain Example 7.
Was obtained. The coating amount in the surface layer of Example 7 was about 160 g / L for Cu-MFI zeolite,
ZrO 2 was about 100 g / L.
【００５０】（実施例８） （１）内層の形成 実施例６と同様の操作を繰り返し、ハニカム触媒体８Ａ
を得た。Example 8 (1) Formation of Inner Layer The same operation as in Example 6 was repeated to obtain a honeycomb catalyst body 8A.
I got
【００５１】（２）中間層の形成 比表面積が約３４０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モル比
が約２８のＨ型モルデナイトを、比表面積が約４８０ｍ
2／ｇのＳｉＯ2に代えた以外は、実施例６と同様の操作
を繰り返し、ハニカム触媒体８Ａに、約２０ｇ／Ｌのコ
ート層を形成したハニカム触媒体８Ｂを得た。(2) Formation of Intermediate Layer H-type mordenite having a specific surface area of about 340 m 2 / g and a SiO 2 / Al 2 O 3 molar ratio of about 28 was prepared.
The same operation as in Example 6 was repeated, except that 2 / g of SiO 2 was used, to obtain a honeycomb catalyst body 8B in which a coat layer of about 20 g / L was formed on the honeycomb catalyst body 8A.
【００５２】（３）表層の形成 Ｈ型βゼオライトを比表面積が約７０ｍ2／ｇのＴｉＯ2
に代えた以外は、実施例６と同様の操作を繰り返し、ハ
ニカム触媒体８Ｂに、Ｃｕ−ＭＦＩゼオライト及びＲｈ
−ＴｉＯ2を、塗布、乾燥及び焼成して実施例８になる
触媒を得た。実施例８の表層におけるコート量は、Ｃｕ
−ＭＦＩゼオライトが約１６０ｇ／Ｌ、Ｒｈ−ＴｉＯ2
が約１００ｇ／Ｌであった。(3) Formation of Surface Layer The H-type β zeolite is made of TiO 2 having a specific surface area of about 70 m 2 / g.
The same operation as in Example 6 was repeated, except that the Cu-MFI zeolite and Rh were added to the honeycomb catalyst body 8B.
The -TiO 2, applied to obtain a dry and calcined catalyst comprising in Example 8. The coating amount in the surface layer of Example 8 was Cu
About 160 g / L of MFI zeolite, Rh-TiO 2
Was about 100 g / L.
【００５３】（実施例９） （１）内層の形成 実施例６と同様の操作を繰り返し、ハニカム触媒体９Ａ
を得た。Example 9 (1) Formation of Inner Layer The same operation as in Example 6 was repeated to obtain a honeycomb catalyst 9A.
I got
【００５４】（２）中間層の形成 比表面積が約３４０ｍ2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モル比
が約２８のＨ型モルデナイトを、比表面積が約４７０ｍ
2／ｇ、ＳｉＯ2／Ａｌ2Ｏ3モル比が約３８のＨ型βゼオ
ライトに代えた以外は、実施例６と同様の操作を繰り返
し、ハニカム触媒体９Ａに、約２０ｇ／Ｌのコート層を
形成したハニカム触媒体９Ｂを得た。(2) Formation of Intermediate Layer H-type mordenite having a specific surface area of about 340 m 2 / g and a SiO 2 / Al 2 O 3 molar ratio of about 28 was prepared.
The same operation as in Example 6 was repeated except that the H type β zeolite having a molar ratio of 2 / g and SiO 2 / Al 2 O 3 of about 38 was used, and the honeycomb catalyst 9A was coated with a coat layer of about 20 g / L. Was formed to obtain a honeycomb catalyst body 9B.
【００５５】（３）表層の形成 Ｈ型βゼオライトを、比表面積が約４８０ｍ2／ｇのＳ
ｉＯ2に代えた以外は、実施例６と同様の操作を繰り返
し、ハニカム触媒体９Ｂに、Ｃｕ−ＭＦＩゼオライト及
びＲｈ−ＳｉＯ2を、塗布、乾燥及び焼成して実施例９
になる触媒を得た。実施例９の表層におけるコート量
は、Ｃｕ−ＭＦＩゼオライトが約１６０ｇ／Ｌ、Ｒｈ−
ＳｉＯ2が約１００ｇ／Ｌであった。(3) Formation of Surface Layer The H-type β zeolite was converted to S-type having a specific surface area of about 480 m 2 / g.
The same operation as in Example 6 was repeated, except that iO 2 was used, and Cu-MFI zeolite and Rh-SiO 2 were coated, dried and calcined on the honeycomb catalyst 9B to obtain Example 9.
Was obtained. The coating amount in the surface layer of Example 9 was about 160 g / L for Cu-MFI zeolite,
SiO 2 was about 100 g / L.
【００５６】（比較例１） （１）内層の形成 ジニトロジアンミン白金水溶液中に、比表面積が約２８
０ｍ2／ｇの活性Ａｌ2Ｏ3粉末を添加し、乾燥、焼成工
程を経てＰｔ−Ａｌ2Ｏ3粉末を得た。得られたＰｔ−Ａ
ｌ2Ｏ3粉末を、実施例１と同様の操作を繰り返し、１平
方インチ断面当たり約４００個の流路を持つコージェラ
イト質ハニカム担体１．０Ｌに塗布、乾燥、焼成してコ
ート量約５０ｇ／Ｌのハニカム触媒Ｒ１を得た。次い
で、得られたハニカム触媒Ｒ１を酢酸バリウム水溶液に
浸した後、１２０℃で乾燥、５００℃で１時間焼成し、
白金を０．５ｇ／Ｌ、バリウムを０．０６５モル／Ｌ含
有するハニカム触媒体Ｒ１Ａを得た。ハニカム触媒体Ｒ
１Ａのコート層における白金の分布をＥＰＭＡで分析し
た結果、白金がコート層に均一に分布していることが確
認された。(Comparative Example 1) (1) Formation of Inner Layer A specific surface area of about 28 in an aqueous dinitrodiammineplatinum solution was measured.
0 m 2 / g of activated Al 2 O 3 powder was added, followed by drying and firing steps to obtain a Pt-Al 2 O 3 powder. Pt-A obtained
The same operation as in Example 1 was repeated to apply l 2 O 3 powder to 1.0 L of cordierite-based honeycomb carrier having about 400 channels per square inch cross section, dried, and fired to coat about 50 g. / L of the honeycomb catalyst R1 was obtained. Next, the obtained honeycomb catalyst R1 was immersed in an aqueous barium acetate solution, dried at 120 ° C., and calcined at 500 ° C. for 1 hour,
A honeycomb catalyst body R1A containing 0.5 g / L of platinum and 0.065 mol / L of barium was obtained. Honeycomb catalyst body R
As a result of analyzing the distribution of platinum in the coat layer of 1A by EPMA, it was confirmed that platinum was uniformly distributed in the coat layer.
【００５７】（２）表層の形成 実施例１と同様の操作を繰り返し、ハニカム触媒体Ｒ１
Ａに、Ｃｕ−ＭＦＩゼオライトを塗布、乾燥及び焼成し
て比較例１になる触媒を得た。比較例１の表層における
コート量は、約２２０ｇ／Ｌであった。(2) Formation of Surface Layer The same operation as in Example 1 was repeated to obtain the honeycomb catalyst body R1.
A was coated with Cu-MFI zeolite, dried and calcined to obtain a catalyst of Comparative Example 1. The coating amount on the surface layer of Comparative Example 1 was about 220 g / L.
【００５８】（比較例２） （１）内層の形成 コージェライト質ハニカム担体１．０Ｌに、実施例１と
同様の操作を繰り返して得られた活性Ａｌ2Ｏ3のスラリ
ーを塗布し、コート層を形成させた。コート層を形成さ
せたハニカム担体を、ジニトロジアンミン白金水溶液中
に浸した後、実施例１と同様の操作を繰り返し、乾燥及
び焼成したハニカム触媒Ｒ２を得た。さらに、ハニカム
触媒Ｒ２を酢酸バリウム水溶液に浸した後、乾燥、焼成
し、バリウムを０．０６５モル／Ｌ、白金を０．５ｇ／
Ｌ含有するハニカム触媒体Ｒ２Ａを得た。ハニカム触媒
体Ｒ２Ａのコート層における白金の分布をＥＰＭＡで分
析した結果、コート層の上半層部に０．１ｇ／Ｌの白金
が検出され、下半層部には０．４／Ｌの白金が検出され
た。Comparative Example 2 (1) Formation of Inner Layer A slurry of active Al 2 O 3 obtained by repeating the same operation as in Example 1 was applied to 1.0 L of cordierite-based honeycomb carrier, and a coat layer was formed. Was formed. After immersing the honeycomb carrier having the coated layer formed therein in an aqueous dinitrodiammine platinum solution, the same operation as in Example 1 was repeated to obtain a dried and fired honeycomb catalyst R2. Further, the honeycomb catalyst R2 was immersed in an aqueous barium acetate solution, dried and calcined to obtain 0.065 mol / L barium and 0.5 g / platinum platinum.
An L-containing honeycomb catalyst body R2A was obtained. As a result of analyzing the distribution of platinum in the coat layer of the honeycomb catalyst body R2A by EPMA, 0.1 g / L of platinum was detected in the upper half layer of the coat layer, and 0.4 / L of platinum was detected in the lower half layer. Was detected.
【００５９】（２）表層の形成 実施例１と同様の操作を繰り返し、ハニカム触媒体Ｒ２
Ａに、Ｃｕ−ＭＦＩゼオライトを塗布、乾燥及び焼成し
て比較例２になる触媒を得た。比較例２の表層における
コート量は、約２２０ｇ／Ｌであった。(2) Formation of Surface Layer The same operation as in Example 1 was repeated to obtain a honeycomb catalyst body R2.
A was coated with Cu-MFI zeolite, dried and calcined to obtain a catalyst of Comparative Example 2. The coating amount in the surface layer of Comparative Example 2 was about 220 g / L.
【００６０】実施例１〜９並びに比較例１及び２の触媒
の触媒構成及びその組成を表１に示す。Table 1 shows the catalyst structures and compositions of the catalysts of Examples 1 to 9 and Comparative Examples 1 and 2.
【００６１】（触媒性能試験例）各例の触媒を、４気筒
２．５Ｌ直接噴射式ディーゼルエンジンを設置したエン
ジンダイナモ装置の排気系に組み込み、触媒による排気
ガス中のＮＯｘの浄化性能を測定した。(Catalyst Performance Test Examples) The catalysts of the respective examples were incorporated into the exhaust system of an engine dynamo apparatus equipped with a 4-cylinder 2.5-liter direct injection diesel engine, and the NOx purification performance of the catalysts was measured. .
【００６２】本エンジンダイナモ装置の排気系には、燃
料を注入するためのノズルが設けられており、触媒入口
における排気ガス中のＨＣ／ＮＯｘ比を制御出来るよう
になっている。触媒のＮＯｘ浄化率測定にあたり、触媒
入口温度を１００〜４５０℃まで、約１００℃／ｍｉｎ
で昇温させ、触媒入口温度２５０℃及び４２０℃におけ
るＮＯｘ浄化率を測定した。触媒入口温度１００〜３０
０℃までの排気ガス中の平均ＨＣ／ＮＯｘ比は０．８で
あり、３００〜４５０℃までの排気ガス中の平均ＨＣ／
ＮＯｘ比は４．１であった。また、本測定時のガス空間
速度は約４００００ｈ-1であった。The exhaust system of the engine dynamo device is provided with a nozzle for injecting fuel, so that the HC / NOx ratio in the exhaust gas at the catalyst inlet can be controlled. In measuring the NOx purification rate of the catalyst, the temperature at the catalyst inlet was increased from 100 to 450 ° C. to about 100 ° C./min.
And the NOx purification rates at the catalyst inlet temperatures of 250 ° C. and 420 ° C. were measured. Catalyst inlet temperature 100-30
The average HC / NOx ratio in the exhaust gas up to 0 ° C. is 0.8, and the average HC / NOx in the exhaust gas up to 300-450 ° C.
The NOx ratio was 4.1. The gas space velocity at the time of the main measurement was about 40,000 h -1 .
【００６３】表１に、各例の触媒の触媒入口温度２５０
℃及び４２０℃におけるＮＯｘ浄化率をを示す。Table 1 shows the catalyst inlet temperature 250 of each of the catalysts.
4 shows the NOx purification rates at 4 ° C. and 420 ° C.
【００６４】[0064]
【表１】 [Table 1]
【００６５】表１から、実施例１〜９の触媒は、いずれ
の温度においても明らかにＮＯｘ浄化率が高く、３００
℃以下での低温域、特に、１５０℃以下を含み、かつＨ
Ｃ／ＮＯｘ比が極めて低い低温域であっても、ＮＯｘを
効率良くトラップし、４００℃以上の高温域に至って
は、ＮＯｘとＨＣを高効率で反応させており、優れたＮ
Ｏｘ浄化能を示している。From Table 1, it can be seen that the catalysts of Examples 1 to 9 had a clearly high NOx purification rate at any temperature,
Low temperature range below 150 ° C., especially below 150 ° C. and H
Even in a low temperature range where the C / NOx ratio is extremely low, NOx is trapped efficiently, and up to a high temperature range of 400 ° C. or higher, NOx and HC are reacted with high efficiency, and excellent N
This shows the ability to purify Ox.
【００６６】[0066]
【発明の効果】以上説明してきたように、本発明によれ
ば、ハニカム状モノリス担体上に積層した触媒層のう
ち、内層の触媒成分に特定の分布をもたせることなどし
たため、低温で、低ＨＣ／ＮＯｘ比の排気ガスであって
も、高効率で浄化する排気ガス浄化用触媒及びその製造
方法を提供することができる。As described above, according to the present invention, the catalyst component in the inner layer of the catalyst layer laminated on the honeycomb-shaped monolithic carrier is provided with a specific distribution. It is possible to provide an exhaust gas purifying catalyst for purifying exhaust gas with a high efficiency even with an exhaust gas having a / NOx ratio and a method for producing the same.
【００６７】また、本発明の排気ガス浄化用触媒を使用
することにより、環境汚染が少なく、経済性（燃費）に
優れた自動車を提供することができる。Further, by using the exhaust gas purifying catalyst of the present invention, it is possible to provide an automobile which is less polluted by the environment and excellent in economy (fuel efficiency).
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｂ０１Ｊ 29/20 Ｂ０１Ｊ 29/76 Ａ 29/72 37/02 ３０１Ｌ 29/76 Ｆ０１Ｎ 3/10 Ａ 37/02 ３０１ 3/20 Ｄ Ｆ０１Ｎ 3/10 3/28 ３０１Ｃ 3/20 Ｂ０１Ｄ 53/36 Ｈ 3/28 ３０１ １０２Ｂ ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI B01J 29/20 B01J 29/76 A 29/72 37/02 301L 29/76 F01N 3/10 A 37/02 301 3/20 D F01N 3/10 3/28 301C 3/20 B01D 53/36 H 3/28 301 102B
Claims (7)
る内層及び表層を順次積層して成る排気ガス浄化用触媒
において、 上記内層が、白金及び／又はパラジウムと、バリウムを
含有し、かつ該白金及び／又はパラジウムの濃度が、上
記ハニカム状モノリス担体の壁面に近い程高く、上記表
層に近い程低い分布を成し、 上記表層が、銅、ロジウム及びコバルトから成る群より
選ばれた少なくとも１種の成分を含有することを特徴と
する排気ガス浄化用触媒。1. An exhaust gas purifying catalyst comprising an inner layer serving as a catalyst layer and a surface layer sequentially stacked on a honeycomb monolithic carrier, wherein the inner layer contains platinum and / or palladium and barium, and And / or the concentration of palladium is higher as it is closer to the wall surface of the honeycomb monolithic carrier and lower as it is closer to the surface layer, and the surface layer is at least one selected from the group consisting of copper, rhodium and cobalt. An exhaust gas purifying catalyst comprising the following components:
と、バリウムを、ＭＦＩゼオライト、モルデナイト、β
ゼオライト、アルミナ、シリカ、シリカ・アルミナ及び
チタニアから成る群より選ばれた少なくとも１種の耐火
性無機化合物に担持して成ることを特徴とする請求項１
記載の排気ガス浄化用触媒。2. The method according to claim 1, wherein the inner layer comprises platinum and / or palladium and barium, and comprises MFI zeolite, mordenite, β
2. The method according to claim 1, wherein the carrier is supported on at least one refractory inorganic compound selected from the group consisting of zeolite, alumina, silica, silica-alumina and titania.
The exhaust gas purifying catalyst according to the above.
から成る群より選ばれた少なくとも１種の成分を、ＭＦ
Ｉゼオライト、モルデナイト、βゼオライト、アルミ
ナ、シリカ、シリカ・アルミナ、チタニア及びジルコニ
アから成る群より選ばれた少なくとも１種の耐火性無機
化合物に担持して成ることを特徴とする請求項１又は２
記載の排気ガス浄化用触媒。3. The method according to claim 1, wherein the surface layer comprises at least one component selected from the group consisting of copper, rhodium and cobalt,
3. The method as claimed in claim 1, wherein the zeolite is supported on at least one refractory inorganic compound selected from the group consisting of I zeolite, mordenite, β zeolite, alumina, silica, silica-alumina, titania and zirconia.
The exhaust gas purifying catalyst according to the above.
ウムの含有量が、上記ハニカム状モノリス触媒１Ｌ当た
り０．１〜１．２ｇであることを特徴とする請求項１〜
３のいずれか１つの項に記載の排気ガス浄化用触媒。4. The method according to claim 1, wherein the content of platinum and / or palladium in the inner layer is 0.1 to 1.2 g per 1 L of the honeycomb monolith catalyst.
Item 3. The exhaust gas purifying catalyst according to any one of Items 3.
上記ハニカム状モノリス触媒１Ｌ当たり０．０３〜０．
３モルであることを特徴とする請求項１〜４のいずれか
１つの項に記載の排気ガス浄化用触媒。5. The content of barium in the inner layer is:
0.03 to 0.1 per liter of the honeycomb monolith catalyst.
The exhaust gas purifying catalyst according to any one of claims 1 to 4, wherein the amount of the catalyst is 3 mol.
オライト、モルデナイト、βゼオライト、アルミナ、シ
リカ、シリカ・アルミナ及びチタニアから成る群より選
ばれた少なくとも１種の耐火性無機化合物を含有する中
間層を設けたことを特徴とする請求項１〜５のいずれか
１つの項に記載の排気ガス浄化用触媒。6. At least one refractory inorganic compound selected from the group consisting of MFI zeolite, mordenite, β zeolite, alumina, silica, silica-alumina and titania is provided between the inner layer and the surface layer. The exhaust gas purifying catalyst according to any one of claims 1 to 5, further comprising an intermediate layer.
の排気ガス浄化用触媒を製造するに当たり、 （１）上記ハニカム状モノリス担体に、上記白金及び／
又はパラジウムを含む水溶液を含浸し、 （２）（１）工程によって得られたハニカム状モノリス
担体に、上記耐火性無機化合物を塗布し、 （３）（２）工程により耐火性無機化合物を塗布したハ
ニカム状モノリス担体を乾燥することにより、上記ハニ
カム状モノリス担体上に内層を積層することを特徴とす
る排気ガス浄化用触媒の製造方法。7. In producing the exhaust gas purifying catalyst according to any one of claims 1 to 6, (1) the platinum and / or platinum is added to the honeycomb monolithic carrier.
Or (2) applying the refractory inorganic compound to the honeycomb monolithic carrier obtained in the step (1), and (3) applying the refractory inorganic compound in the step (2). A method for producing an exhaust gas purifying catalyst, characterized in that an inner layer is laminated on the honeycomb monolith carrier by drying the honeycomb monolith carrier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10099942A JPH11276907A (en) | 1998-03-30 | 1998-03-30 | Catalyst for purifying exhaust gas and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10099942A JPH11276907A (en) | 1998-03-30 | 1998-03-30 | Catalyst for purifying exhaust gas and its production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11276907A true JPH11276907A (en) | 1999-10-12 |
Family
ID=14260776
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10099942A Pending JPH11276907A (en) | 1998-03-30 | 1998-03-30 | Catalyst for purifying exhaust gas and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11276907A (en) |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2799665A1 (en) * | 1999-10-15 | 2001-04-20 | Toyota Motor Co Ltd | Catalyst, for exhaust gas purification, includes inorganic oxide layer containing noble and transition metals to protect nitrogen oxide absorber from poisoning by sulfur oxides |
| US6806225B1 (en) | 1998-06-30 | 2004-10-19 | Toyota Jidosha Kabushiki Kaisha | Catalyst for exhaust gas purification, process for producing the same, and method of purifying exhaust gas |
| JP2008513733A (en) * | 2004-08-12 | 2008-05-01 | サウスウエスト リサーチ インスティテュート | Component evaluation using non-engine-based test systems (component evaluation using non-engineered tests system) |
| JP2010516445A (en) * | 2007-01-17 | 2010-05-20 | ナノステラー インコーポレイテッド | Engine exhaust gas catalyst containing palladium-gold |
| US7763560B2 (en) | 2003-05-06 | 2010-07-27 | Ict Co., Ltd | Catalyst for purifying diesel engine exhaust gas and method for production thereof |
| JP2012515085A (en) * | 2009-01-16 | 2012-07-05 | ビー・エイ・エス・エフ、コーポレーション | Diesel oxidation catalyst composite with layer structure for carbon monoxide and hydrocarbon conversion |
| JP2012517343A (en) * | 2009-02-25 | 2012-08-02 | エルジー・ハウシス・リミテッド | Catalyst body and method for removing formaldehyde using the same |
| US8258070B2 (en) | 2006-11-27 | 2012-09-04 | WGCH Technology Limited | Engine exhaust catalysts containing palladium-gold |
| JP2017070901A (en) * | 2015-10-07 | 2017-04-13 | 本田技研工業株式会社 | Exhaust gas purification catalyst and production method therefor |
| EP2579983B1 (en) | 2010-06-10 | 2018-03-07 | Basf Se | Nox storage catalyst with reduced rh loading |
| US10376867B2 (en) | 2011-10-06 | 2019-08-13 | Johnson Matthey Public Limited Company | Oxidation catalyst for internal combustion engine exhaust gas treatment |
| JP2020517456A (en) * | 2017-04-24 | 2020-06-18 | ジョンソン、マッセイ、パブリック、リミテッド、カンパニーＪｏｈｎｓｏｎ Ｍａｔｔｈｅｙ Ｐｕｂｌｉｃ Ｌｉｍｉｔｅｄ Ｃｏｍｐａｎｙ | Passive NOx adsorber |
| WO2023182270A1 (en) * | 2022-03-22 | 2023-09-28 | 三井金属鉱業株式会社 | Exhaust gas purification catalyst |
-
1998
- 1998-03-30 JP JP10099942A patent/JPH11276907A/en active Pending
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6806225B1 (en) | 1998-06-30 | 2004-10-19 | Toyota Jidosha Kabushiki Kaisha | Catalyst for exhaust gas purification, process for producing the same, and method of purifying exhaust gas |
| FR2799665A1 (en) * | 1999-10-15 | 2001-04-20 | Toyota Motor Co Ltd | Catalyst, for exhaust gas purification, includes inorganic oxide layer containing noble and transition metals to protect nitrogen oxide absorber from poisoning by sulfur oxides |
| US7763560B2 (en) | 2003-05-06 | 2010-07-27 | Ict Co., Ltd | Catalyst for purifying diesel engine exhaust gas and method for production thereof |
| JP2008513733A (en) * | 2004-08-12 | 2008-05-01 | サウスウエスト リサーチ インスティテュート | Component evaluation using non-engine-based test systems (component evaluation using non-engineered tests system) |
| US8258070B2 (en) | 2006-11-27 | 2012-09-04 | WGCH Technology Limited | Engine exhaust catalysts containing palladium-gold |
| JP2010516445A (en) * | 2007-01-17 | 2010-05-20 | ナノステラー インコーポレイテッド | Engine exhaust gas catalyst containing palladium-gold |
| JP2012515085A (en) * | 2009-01-16 | 2012-07-05 | ビー・エイ・エス・エフ、コーポレーション | Diesel oxidation catalyst composite with layer structure for carbon monoxide and hydrocarbon conversion |
| JP2012517343A (en) * | 2009-02-25 | 2012-08-02 | エルジー・ハウシス・リミテッド | Catalyst body and method for removing formaldehyde using the same |
| EP2579983B1 (en) | 2010-06-10 | 2018-03-07 | Basf Se | Nox storage catalyst with reduced rh loading |
| US10376867B2 (en) | 2011-10-06 | 2019-08-13 | Johnson Matthey Public Limited Company | Oxidation catalyst for internal combustion engine exhaust gas treatment |
| JP2017070901A (en) * | 2015-10-07 | 2017-04-13 | 本田技研工業株式会社 | Exhaust gas purification catalyst and production method therefor |
| JP2020517456A (en) * | 2017-04-24 | 2020-06-18 | ジョンソン、マッセイ、パブリック、リミテッド、カンパニーＪｏｈｎｓｏｎ Ｍａｔｔｈｅｙ Ｐｕｂｌｉｃ Ｌｉｍｉｔｅｄ Ｃｏｍｐａｎｙ | Passive NOx adsorber |
| WO2023182270A1 (en) * | 2022-03-22 | 2023-09-28 | 三井金属鉱業株式会社 | Exhaust gas purification catalyst |
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