JP3991908B2

JP3991908B2 - Exhaust gas purification method

Info

Publication number: JP3991908B2
Application number: JP2003103749A
Authority: JP
Inventors: 卓弥池田; 真紀上久保
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 2003-04-08
Filing date: 2003-04-08
Publication date: 2007-10-17
Anticipated expiration: 2022-10-17
Also published as: JP2003326165A

Description

【０００１】
【発明の属する技術分野】
本発明は、自動車等の内燃機関から排出される排ガスの浄化方法に関するものである。
【０００２】
【従来の技術】
自動車等の内燃機関の排ガス浄化用触媒としては、一酸化炭素（ＣＯ）及び炭化水素（ＨＣ）の酸化と、窒素酸化物（ＮＯｘ）の還元を同時に行なう触媒が汎用されている。このような触媒は、例えば特公昭５８−２０３０７号公報にもみられるように、耐火性担体上のアルミナコート層に、パラジウム（Ｐｄ）、白金（Ｐｔ）及びロジウム（Ｒｈ）の貴金属、並びに場合により助触媒成分としてセリウム（Ｃｅ）、ランタン（Ｌａ）等の希土類金属又はニッケル（Ｎｉ）等のベースメタル酸化物を添加したものがほとんどである。
【０００３】
かかる触媒は、排ガス温度とエンジンの設定空燃比の影響を強く受ける。自動車用触媒が浄化能を発揮する排ガス温度としては、一般に３００℃以上必要であり、また空燃比は、ＨＣとＣＯの酸化とＮＯｘの還元のバランスがとれる理論空燃比（Ａ／Ｆ＝１４．６）付近で触媒が最も有効に働く。従って、従来の三元触媒を用いる排ガス浄化装置を取り付けた自動車では、三元触媒が有効に働くような位置に設置されており、また排気系の酸素濃度を検出して、混合気を理論空燃比付近に保つようフィードバック制御が行なわれている。
【０００４】
従来の三元触媒をエキゾーストマニホールド直後に設置しても、排ガス温度が低い（３００℃以下）エンジン始動直後には触媒活性が低く、始動直後（コールドスタート時）に大量に排出されるＨＣは浄化されずにそのまま排出されてしまうという問題がある。
【０００５】
上記の課題を解決するための排ガス浄化装置として、触媒コンバータの排気上流側にコールドＨＣを吸着するための吸着剤を納めたＨＣトラッパーを配置したものが特開平２−１３５１２６号公報や特開平３−１４１８１６号公報に提案されている。
【０００６】
【発明が解決しようとする課題】
しかしながら、特開平２−１３５１２６号公報に記載されている自動車排気ガス浄化装置では、
（１）吸着材の下流側に触媒成分を含浸しているため、触媒が活性温度に達する前に上流側の吸着材からＨＣが脱離してしまう。
（２）ゼオライトへ触媒金属溶液を含浸しているため、触媒成分の耐久性に乏しい。また、特開平３−１４１８１６号公報に記載されている排気ガス浄化装置では、
（３）吸着したＨＣの脱離制御を温度センサ、バイパス管、制御装置等を用いて行なっているため、システムが複雑で信頼性や排気レイアウト上実用的ではない。
という問題があった。
【０００７】
従って、本発明の目的は、上記従来技術に存在する問題を解決し、エンジン始動時に排出される高濃度のＨＣを効率よく吸着し、吸着層からＨＣが脱離し始める温度においても脱離したＨＣが効率よく浄化される排ガス浄化方法を提供することにある。
【０００８】
【課題を解決するための手段】
本発明者等は、上記の従来技術に存在する問題に着目し、ＨＣ吸着に有効なゼオライト層上に触媒層を備えたことを特徴とする吸着触媒の製造方法を特願平５−２７３７８０号及び特願平５−２７３７８１号公報で提案した。これらの方法で得られた触媒は表層の触媒層が内層のゼオライトよりも早く加熱されるため、ゼオライト層からＨＣが脱離する段階において触媒層が活性化されており、ＨＣが良好に浄化される。
本発明者等は更に鋭意研究を重ねた結果、上記吸着触媒を床下位置に装着し、エンジン始動直後に緩やかに加速し又は低速走行を続けた場合、表層の触媒層が活性化する前に内層のゼオライト層から吸着していたＨＣの一部が脱離するため、エンジン始動時に排出されたＨＣの浄化能が少し低下するということがわかった。
【０００９】
本発明は、上記問題点を解決するために、排ガスを、ヒータを用いず、プリ三元触媒、触媒Ａ及び吸着触媒Ｂに順次通過させて浄化する排ガス浄化方法であって、
上記触媒Ａは、炭化水素、一酸化炭素及び窒素酸化物を理論空燃比近傍で浄化する三元触媒をハニカム担体にコーティングして成り、
上記吸着触媒Ｂは、ハニカム担体に、炭化水素の吸着に有効なゼオライト層を下層として、炭化水素を浄化し得る触媒層を上層として配して成ることを特徴とする排ガス浄化方法に関するものである。
【００１０】
また、流入側の触媒Ａと流出側の吸着触媒Ｂの距離は任意でよいが、近すぎると背圧上昇によるエンジン性能の低下を引き起こす可能性があり、逆に離れすぎていると、流出側の吸着触媒表層の触媒温度が上がらず脱離ＨＣの浄化率が低下する可能性もある。従って、触媒Ａと吸着触媒Ｂの距離は１０〜５０ｍｍの範囲とするのが好ましい。
【００１１】
上記吸着触媒Ｂとしては、ゼオライト層上に活性セリア及び／又はアルミナを主成分とした粉末に触媒成分として白金（Ｐｔ）、パラジウム（Ｐｄ）及びロジウム（Ｒｈ）から成る群より選ばれた少なくとも１種の貴金属を含む触媒層を備えるものが好ましい。
【００１２】
本発明で使用される担体は、モノリス型のハニカム形状のもので、コージエライト質担体、メタル担体等任意のものが使用される。
【００１３】
一般的にゼオライトは低温時にＨＣを吸着し、昇温とともに脱離する。触媒がある温度で急激に活性化するのに対し、ゼオライトからの脱離は温度上昇に対してある分布を持って排出される。そして、排ガス温度の上昇に伴い、吸着触媒前に配置した触媒も活性化し、反応熱によって触媒出口温度、即ち吸着触媒入口温度が上昇する。この温度上昇によって吸着触媒表層の触媒も早く活性化するため、ゼオライト層から吸着していたＨＣが脱離するときに、効率よく浄化することができる。しかも、吸着触媒前に触媒を配置することにより、ゼオライト層の温度上昇も抑えられるため吸着能も向上する。
【００１４】
ゼオライトには多くの種類があるが、本発明の吸着触媒Ｂに用いるゼオライトとしては、常温ないし比較的高い温度まで水存在雰囲気下でも充分なＨＣ吸着能を有し、且つ耐久性の高いものを適宜選択する。例えば、モルデナイト、ＵＳＹ、βゼオライト、ＺＳＭ−５等が挙げられる。排ガス中の多種類のＨＣを効率よく吸着するためには、細孔構造の異なるゼオライトを２種以上混合するのがより好ましい。
【００１５】
各種ゼオライトはＨ型でも十分な吸着能力を有するが、Ｐｄ、Ａｇ、Ｃｕ、Ｃｒ、Ｃｏ、Ｎｄ等の金属をイオン交換法、含浸法、浸漬法等の通常の方法を用いて担持したゼオライトが、吸着特性及び脱離抑制能を更に向上することができるため好ましい。各担持量は任意でよいが、例えば０．１〜１５重量％位が好ましい。０．１重量％より少ないと吸着特性及び脱離抑制効果が少なく、逆に１５重量％を超えても効果は変わらない。
【００１６】
【実施例】
以下、本発明を実施例、比較例及び試験例により更に詳細に説明する。尚、例中の「部」は特記しない限り重量部を表す。
【００１７】
（実施例１）
Ｐｔを担持した活性セリア粉末（以下、Ｐｔ／ＣｅＯ_２と記す）１００部、アルミナ５０部、２％硝酸１５０部を磁気ポットに仕込み、振動ミル装置で４０分間、若しくはユニバーサルボールミル装置で６．５時間混合粉砕して、ウォッシュコートスラリーを製造した。コーディエライト製モノリス担体を吸引コート法で給水処理した後、上記製造したスラリーを担体断面全体に均一に投入し、吸引コート法で余分なスラリーを除去した。その後、乾燥を行い、４００℃で１時間仮焼成した。これにより、Ｐｔ／ＣｅＯ_２層が１００ｇ／Ｌコート量で担体にコートされた。上記ウォシュコート、乾燥、焼成を更に繰り返して合計２００ｇ／ＬのＰｔ／ＣｅＯ_２層をコートした。
次に、Ｒｈを担持したアルミナ粉末（以下、Ｒｈ／Ａｌ_２Ｏ_３と記す）１００部、アルミナ５０部、２％硝酸１５０部を磁器ポットに仕込み、上記と同様にしてウォシュコートスラリーを製造し、同方法でＰｔ／ＣｅＯ_２層の上に５０ｇ／ＬのＲｈ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥後、空気雰囲気６５０℃で３時間の焼成を行い、排気流入側の（触媒Ａ１）を得た。
また、Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）（以下ＺＳＭ−５と記す）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部及び水１５部を磁性ポットに仕込み、上記と同様にしてＺＳＭ−５スラリーを製造し、同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、４００℃で１時間焼成を行った。
上記と同様にしてＺＳＭ−５層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、４００℃で１時間焼成を行った。更にＰｔ／ＣｅＯ_２層の上にＲｈ／Ａｌ_２Ｏ_３触媒層を５０ｇ／Ｌコートし、乾燥後、空気雰囲気６５０℃で３時間の焼成を行い、排気流出側の（吸着触媒Ｂ１）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１）を組合せ、（タンデム型吸着触媒−１）を得た。
【００１８】
（実施例２）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部及び水１５部を磁性ポットに仕込み、実施例１と同様にしてＺＳＭ−５スラリーを製造し、同方法でモノリス担体上に１５０ｇ／Ｌコート、乾燥、４００℃で１時間焼成を行なった。
次に、Ｐｄを担持したアルミナ粉末（以下、Ｐｄ／Ａｌ_２Ｏ_３と記す）１００部、アルミナ５０部、２％硝酸１５０部を磁器ポットに仕込み、実施例１と同方法でウォシュコートスラリーを製造し、同コート方法でＺＳＭ−５層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３層をコートし、乾燥、焼成を行なった。
更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２）を組合せ、（タンデム型吸着触媒−２）を得た。
【００１９】
（実施例３）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）（以下ＵＳＹと記す）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５とＵＳＹの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ３）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ３）を組合せ、（タンデム型吸着触媒−３）を得た。
【００２０】
（実施例４）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５とＵＳＹの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ４）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ４）を組合せ、（タンデム型吸着触媒−４）を得た。
【００２１】
（実施例５）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）６７部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５とＵＳＹの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ５）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ５）を組合せ、（タンデム型吸着触媒−５）を得た。
【００２２】
（実施例６）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）６７部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５とＵＳＹの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ６）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ６）を組合せ、（タンデム型吸着触媒−６）を得た。
【００２３】
（実施例７）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ｈ型モルデナイト（以下モルデナイトと記す）（ＳｉＯ_２／Ａｌ_２Ｏ_３＝２００）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とモルデナイトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５とモルデナイトの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ７）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ７）を組合せ、（タンデム型吸着触媒−７）を得た。
【００２４】
（実施例８）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ｈ型モルデナイト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝２００）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とモルデナイトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５とモルデナイトの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／Ａｌ２Ｏ３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ８）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ８）を組合せ、（タンデム型吸着触媒−８）を得た。
【００２５】
（実施例９）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ｈ型βゼオライト（以下βゼオライトと記す）（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とβゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５とβゼオライトの混合層の上に１００ｇ／ＬのＰｔ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ９）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ９）を組合せ、（タンデム型吸着触媒−９）を得た。
【００２６】
（実施例１０）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とβゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５とβゼオライトの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１０）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１０）を組合せ、（タンデム型吸着触媒−１０）を得た。
【００２７】
（実施例１１）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）６７部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とβゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５とβゼオライトの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１１）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１１）を組合せ、（タンデム型吸着触媒−１１）を得た。
【００２８】
（実施例１２）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）６７部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５とβゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５とβゼオライトの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１２）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１２）を組合せ、（タンデム型吸着触媒−１２）を得た。
【００２９】
（実施例１３）
Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＵＳＹスラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＵＳＹ層の上に１００ｇ／ＬのＰｔ／ＣｅＯ２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ２Ｏ３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１３）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１３）を組合せ、（タンデム型吸着触媒−１３）を得た。
【００３０】
（実施例１４）
Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＵＳＹスラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＵＳＹ層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１４）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１４）を組合せ、（タンデム型吸着触媒−１４）を得た。
【００３１】
（実施例１５）
Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でβゼオライトスラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でβゼオライト層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ２Ｏ３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１５）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１５）を組合せ、（タンデム型吸着触媒−１５）を得た。
【００３２】
（実施例１６）
Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でβゼオライトスラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でβゼオライト層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１６）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１６）を組合せ、（タンデム型吸着触媒−１６）を得た。
【００３３】
（実施例１７）
Ｈ型モルデナイト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝２００）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でモルデナイトスラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でモルデナイト層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１７）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１７）を組合せ、（タンデム型吸着触媒−１７）を得た。
【００３４】
（実施例１８）
Ｈ型モルデナイト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝２００）１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でモルデナイトスラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でモルデナイト層の上に１００ｇ／ＬのＰｔ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１８）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１８）を組合せ、（タンデム型吸着触媒−１８）を得た。
【００３５】
（実施例１９）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、Ｈ型モルデナイト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝２００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、ＵＳＹ、モルデナイトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５、ＵＳＹ、モルデナイトの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ１９）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ１９）を組合せ、（タンデム型吸着触媒−１９）を得た。
【００３６】
（実施例２０）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、Ｈ型モルデナイト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝２００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、ＵＳＹ、モルデナイトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５、ＵＳＹ、モルデナイトの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２０）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２０）を組合せ、（タンデム型吸着触媒−２０）を得た。
【００３７】
（実施例２１）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、ＵＳＹ、βゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５、ＵＳＹ、βゼオライトの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２１）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２１）を組合せ、（タンデム型吸着触媒−２１）を得た。
【００３８】
（実施例２２）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、ＵＳＹ、βゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５、ＵＳＹ、βゼオライトの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２２）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２２）を組合せ、（タンデム型吸着触媒−２２）を得た。
【００３９】
（実施例２３）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ａｇをイオン交換したＺＳＭ−５（以下、Ａｇ−ＺＳＭ−５と記す）（Ａｇ担持量５重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、ＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、ＵＳＹの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２３）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２３）を組合せ、（タンデム型吸着触媒−２３）を得た。
【００４０】
（実施例２４）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ａｇ担持ＺＳＭ−５（Ａｇ担持量５重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、ＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、ＵＳＹの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２４）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２４）を組合せ、（タンデム型吸着触媒−２４）を得た。
【００４１】
（実施例２５）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｐｄをイオン交換したＺＳＭ−５（以下、Ｐｄ−ＺＳＭ−５と記す）（Ｐｄ担持量２重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、ＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、ＵＳＹの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２５）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２５）を組合せ、（タンデム型吸着触媒−２５）を得た。
【００４２】
（実施例２６）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｐｄ担持ＺＳＭ−５（Ｐｄ担持量２重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、ＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、ＵＳＹの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２６）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２６）を組合せ、（タンデム型吸着触媒−２６）を得た。
【００４３】
（実施例２７）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ａｇ担持ＺＳＭ−５（Ａｇ担持量５重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、βゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、βゼオライトの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２７）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２７）を組合せ、（タンデム型吸着触媒−２７）を得た。
【００４４】
（実施例２８）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ａｇ担持ＺＳＭ−５（Ａｇ担持量５重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、βゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５、Ａｇ−ＺＳＭ−５、βゼオライトの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２８）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２８）を組合せ、（タンデム型吸着触媒−２８）を得た。
【００４５】
（実施例２９）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｐｄ担持ＺＳＭ−５（Ｐｄ担持量２重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、βゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、βゼオライトの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ２９）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ２９）を組合せ、（タンデム型吸着触媒−２９）を得た。
【００４６】
（実施例３０）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）３４部、Ｐｄ担持ＺＳＭ−５（Ｐｄ担持量２重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝３０）３３部、Ｈ型βゼオライト（ＳｉＯ_２／Ａｌ_２Ｏ_３＝１００）３３部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、βゼオライトの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５、Ｐｄ−ＺＳＭ−５、βゼオライトの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ３０）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ３０）を組合せ、（タンデム型吸着触媒−３０）を得た。
【００４７】
（実施例３１）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ａｇをイオン交換したＵＳＹ（以下、Ａｇ−ＵＳＹと記す）（Ａｇ担持量５重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝１２）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ａｇ−ＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例１と同方法でＺＳＭ−５、Ａｇ−ＵＳＹの混合層の上に１００ｇ／ＬのＰｔ／ＣｅＯ_２触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｔ／ＣｅＯ_２層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ３１）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ３１）を組合せ、（タンデム型吸着触媒−３１）を得た。
【００４８】
（実施例３２）
Ｈ型ＺＳＭ−５（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７００）５０部、Ａｇ−ＵＳＹ（Ａｇ担持量５重量％、ＳｉＯ_２／Ａｌ_２Ｏ_３＝１２）５０部、シリカゾル（固形分２０％）２１５部、１０％硝酸１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でＺＳＭ−５、Ａｇ−ＵＳＹの混合スラリーを製造した。そして、実施例１と同方法でモノリス担体上に１５０ｇ／Ｌコートし、乾燥、焼成を行った。
次に、実施例２と同方法でＺＳＭ−５、Ａｇ−ＵＳＹの混合層の上に１００ｇ／ＬのＰｄ／Ａｌ_２Ｏ_３触媒層をコートし、乾燥、焼成を行った。更に、実施例１と同方法でＲｈ／Ａｌ_２Ｏ_３触媒層をＰｄ／Ａｌ_２Ｏ_３層上に５０ｇ／Ｌコートし、乾燥、焼成を行い、（吸着触媒Ｂ３２）を得た。
排気流入側に（触媒Ａ１）、排気流出側に（吸着触媒Ｂ３２）を組合せ、（タンデム型吸着触媒−３２）を得た。
【００４９】
（実施例３３）
実施例１と同方法でＰｄ／ＣｅＯ_２層を２００ｇ／Ｌコートし、乾燥、焼成を行った。更に、同方法でＰｄ／ＣｅＯ_２層上にＲｈ／Ａｌ２Ｏ３層を５０ｇ／Ｌコートし、乾燥後、雰囲気６５０℃で３時間の焼成を行い、（触媒Ａ２）を得た。
排気流入側に（触媒Ａ２）、排気流出側に（吸着触媒Ｂ５）を組合せ、（タンデム型吸着触媒−３３）を得た。
【００５０】
（実施例３４）
排気流入側に（触媒Ａ２）、排気流出側に（吸着触媒Ｂ９）を組合せ、（タンデム型吸着触媒−３３）を得た。
【００５１】
（比較例１）
Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝５０）を１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸水１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でウォッシュコートスラリーを製造し、同コート方法でモノリス担体に１５０ｇ／Ｌコート、乾燥、焼成を行ない、（吸着触媒Ｂ３５）を得た。排気流入側に（吸着触媒３５）、排出流出側に（触媒Ａ１）を組合せ、（タンデム型吸着触媒−３５）を得た。
【００５２】
（比較例２）
Ｈ型ＵＳＹ（ＳｉＯ_２／Ａｌ_２Ｏ_３＝７）を１００部、シリカゾル（固形分２０％）２１５部、１０％硝酸水１００部、水１５部を磁器ポットに仕込み、実施例１と同方法でウォッシュコートスラリーを製造し、同コート方法でモノリス担体に１５０ｇ／Ｌコート、乾燥、焼成を行ない、（吸着触媒−３６）を得た。
排気流入側に（吸着触媒Ｂ３６）、排出流出側に（触媒Ａ１）を組合せ、（タンデム型吸着触媒−３６）を得た。
【００５３】
（比較例３）
排気流入側に（吸着触媒Ｂ１３）、排気流出側に（触媒Ａ１）を組合せ、（タンデム型吸着触媒−３７）を得た。
【００５４】
［試験例］
実施例１〜３４及び比較例１〜４の触媒Ａと吸着触媒Ｂを用いたタンデム型吸着触媒を使用して下記評価条件でＨＣ吸着・浄化特性評価（ＦＴＰ７５Ａｂａｇ）を日産自動車（株）製車両（排気量３リットル）を用いて行った。各吸着触媒Ｂの浄化特性は吸着触媒未装着システム（触媒Ａのみ）と性能比較を行なった。
即ち、評価は、
（１）エンジン始動時に排出されるＨＣの吸着能を評価するためＡｂａｇ０〜１２５秒間のエミッション低減率を測定し、
（２）エンジン始動時及び昇温後のＨＣの吸着浄化能を評価するためＡｂａｇ０〜５０５秒間のエミッション低減率を測定した。
【００５５】

【００５６】
尚、評価に当たっては図１示すようにエンジン１のエギゾーストマニホールド２にプリ三元触媒３（０．５Ｌ）として４０ｇ／ｃｆのＰｔ／ＲｈがＰｔ：Ｒｈ＝５：１の比で担持した触媒を、８５０℃で１００時間エンジン耐久（燃焼カット有）したＰｔ−Ｒｈ系触媒の耐久品を配置し、床下三元触媒Ａ４（１．３Ｌ）の後に吸着触媒Ｂ５（１．３Ｌ）を装着した排ガス浄化装置を用い、吸着触媒Ｂ未装着の場合と性能比較を行った。評価結果を表１に示す。
【００５７】
【表１】

【００５８】
【発明の効果】
以上説明してきたように、本発明の排ガス浄化方法においては、担体上に触媒活性成分を含む無機物をコートした触媒を排気流入側に配置し、担体上にＨＣ吸着に有効なゼオライトから成る吸着層がコートされた吸着触媒を排気流出側に配置することにより、吸着層からＨＣが脱離し始める温度においても、脱離したＨＣが良好に浄化される。
【図面の簡単な説明】
【図１】試験例に用いた排ガス浄化装置の系統図である。
【符号の説明】
１エンジン
２エキゾ−ストマニホールド
３プリ三元触媒
４触媒Ａ
５吸着触媒Ｂ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for purifying exhaust gas discharged from an internal combustion engine such as an automobile.
[0002]
[Prior art]
As an exhaust gas purifying catalyst for an internal combustion engine such as an automobile, a catalyst that performs oxidation of carbon monoxide (CO) and hydrocarbon (HC) and reduction of nitrogen oxide (NOx) simultaneously is widely used. Such a catalyst includes, for example, a precious metal such as palladium (Pd), platinum (Pt) and rhodium (Rh) on an alumina coat layer on a refractory support, as seen in Japanese Patent Publication No. 58-20307. Most of the promoter components include rare earth metals such as cerium (Ce) and lanthanum (La) or base metal oxides such as nickel (Ni).
[0003]
Such a catalyst is strongly influenced by the exhaust gas temperature and the set air-fuel ratio of the engine. The exhaust gas temperature at which the automobile catalyst exhibits the purifying ability is generally required to be 300 ° C. or higher, and the air-fuel ratio is the stoichiometric air-fuel ratio (A / F = 14.14) that balances the oxidation of HC and CO and the reduction of NOx. 6) The catalyst works most effectively in the vicinity. Therefore, an automobile equipped with a conventional exhaust gas purification device using a three-way catalyst is installed at a position where the three-way catalyst works effectively, and the oxygen concentration in the exhaust system is detected and the air-fuel mixture is theoretically empty. Feedback control is performed so as to maintain the fuel ratio in the vicinity.
[0004]
Even if a conventional three-way catalyst is installed immediately after the exhaust manifold, the exhaust gas temperature is low (300 ° C or less). The catalyst activity is low immediately after the engine is started, and the HC that is discharged in large quantities immediately after the start (cold start) is purified. There is a problem that it is discharged as it is.
[0005]
As an exhaust gas purifying apparatus for solving the above-mentioned problems, Japanese Patent Application Laid-Open No. 2-135126 and Japanese Patent Application Laid-Open No. Hei 3 are those in which an HC trapper containing an adsorbent for adsorbing cold HC is disposed on the exhaust upstream side of a catalytic converter. -141816.
[0006]
[Problems to be solved by the invention]
However, in the automobile exhaust gas purification device described in JP-A-2-135126,
(1) Since the catalyst component is impregnated on the downstream side of the adsorbent, HC is desorbed from the upstream adsorbent before the catalyst reaches the activation temperature.
(2) Since the catalyst metal solution is impregnated into zeolite, the durability of the catalyst component is poor. Moreover, in the exhaust gas purifying apparatus described in Japanese Patent Laid-Open No. 3-141816,
(3) Since the desorption control of the adsorbed HC is performed using a temperature sensor, a bypass pipe, a control device, etc., the system is complicated and not practical in terms of reliability and exhaust layout.
There was a problem.
[0007]
Accordingly, an object of the present invention is to solve the problems existing in the above-mentioned prior art, efficiently adsorb high-concentration HC discharged at engine start, and desorb even at a temperature at which HC begins to desorb from the adsorption layer. An object of the present invention is to provide an exhaust gas purification method that efficiently purifies gas.
[0008]
[Means for Solving the Problems]
The present inventors paid attention to the problems existing in the above-mentioned prior art, and disclosed a method for producing an adsorbent catalyst comprising a catalyst layer on a zeolite layer effective for HC adsorption. Japanese Patent Application No. 5-273780 And in Japanese Patent Application No. 5-273811. In the catalyst obtained by these methods, the surface catalyst layer is heated faster than the inner layer zeolite, so the catalyst layer is activated at the stage where HC is desorbed from the zeolite layer, and the HC is purified well. The
As a result of further earnest research, the present inventors have mounted the adsorbent catalyst under the floor, and when the engine is slowly accelerated immediately after the engine is started or runs at a low speed, the inner layer is activated before the surface catalyst layer is activated. It was found that the ability to purify HC discharged at the start of the engine is slightly reduced because part of the HC adsorbed from the zeolite layer is desorbed.
[0009]
In order to solve the above problems, the present invention is an exhaust gas purification method for purifying exhaust gas by sequentially passing through a pre three-way catalyst, a catalyst A and an adsorption catalyst B without using a heater,
The catalyst A is formed by coating a honeycomb carrier with a three-way catalyst that purifies hydrocarbon, carbon monoxide, and nitrogen oxide in the vicinity of the theoretical air-fuel ratio,
The adsorption catalyst B is a honeycomb carrier with a zeolite layer effective for hydrocarbon adsorption as a lower layer. Can purify hydrocarbons The present invention relates to an exhaust gas purification method characterized by comprising a catalyst layer as an upper layer.
[0010]
In addition, the distance between the inflow side catalyst A and the outflow side adsorption catalyst B may be arbitrary, but if it is too close, it may cause a decrease in engine performance due to an increase in back pressure. There is also a possibility that the catalyst temperature of the surface layer of the adsorbed catalyst does not rise and the purification rate of desorbed HC decreases. Therefore, the distance between the catalyst A and the adsorption catalyst B is preferably in the range of 10 to 50 mm.
[0011]
The adsorption catalyst B is at least one selected from the group consisting of a powder mainly composed of active ceria and / or alumina on a zeolite layer and platinum (Pt), palladium (Pd) and rhodium (Rh) as catalyst components. What comprises the catalyst layer containing a seed noble metal is preferable.
[0012]
The carrier used in the present invention has a monolithic honeycomb shape, and an arbitrary carrier such as a cordierite carrier or a metal carrier is used.
[0013]
In general, zeolite adsorbs HC at a low temperature and desorbs as the temperature rises. Whereas the catalyst is activated rapidly at a certain temperature, the desorption from the zeolite is discharged with a certain distribution as the temperature increases. As the exhaust gas temperature rises, the catalyst disposed before the adsorption catalyst is also activated, and the catalyst outlet temperature, that is, the adsorption catalyst inlet temperature rises due to the reaction heat. This temperature rise also activates the catalyst on the surface of the adsorption catalyst early, so that when HC adsorbed from the zeolite layer is desorbed, it can be efficiently purified. Moreover, by arranging the catalyst before the adsorption catalyst, the temperature rise of the zeolite layer can be suppressed, so that the adsorption ability is also improved.
[0014]
There are many types of zeolite, but as the zeolite used in the adsorption catalyst B of the present invention, a zeolite having sufficient HC adsorption ability and high durability even in a water-present atmosphere from room temperature to a relatively high temperature. Select as appropriate. Examples thereof include mordenite, USY, β zeolite, ZSM-5 and the like. In order to efficiently adsorb many kinds of HC in the exhaust gas, it is more preferable to mix two or more kinds of zeolites having different pore structures.
[0015]
Various types of zeolites have sufficient adsorption ability even in the H type, but zeolites supporting metals such as Pd, Ag, Cu, Cr, Co, and Nd using ordinary methods such as an ion exchange method, an impregnation method, and an immersion method are available. It is preferable because adsorption characteristics and desorption suppression ability can be further improved. Each supported amount may be arbitrary, but is preferably about 0.1 to 15% by weight, for example. If the amount is less than 0.1% by weight, the adsorption characteristics and the desorption suppression effect are small. Conversely, if the amount exceeds 15% by weight, the effect is not changed.
[0016]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples, and Test Examples. In the examples, “parts” represents parts by weight unless otherwise specified.
[0017]
Example 1
Active ceria powder supporting Pt (hereinafter referred to as Pt / CeO) ₂ 100 parts, 50 parts of alumina, and 150 parts of 2% nitric acid were charged in a magnetic pot and mixed and ground for 40 minutes with a vibration mill device or 6.5 hours with a universal ball mill device to produce a washcoat slurry. After the cordierite monolith carrier was supplied with water by the suction coating method, the slurry produced above was uniformly introduced to the entire cross section of the carrier, and the excess slurry was removed by the suction coating method. Then, it dried and pre-baked at 400 degreeC for 1 hour. As a result, Pt / CeO ₂ The layer was coated on the carrier at a coat weight of 100 g / L. The above washcoat, drying, and firing are further repeated until a total of 200 g / L of Pt / CeO. ₂ The layer was coated.
Next, alumina powder carrying Rh (hereinafter Rh / Al ₂ O ₃ 100 parts, 50 parts of alumina, 150 parts of 2% nitric acid are charged into a porcelain pot, and a washcoat slurry is produced in the same manner as described above, and Pt / CeO is prepared by the same method. ₂ 50g / L Rh / Al on the layer ₂ O ₃ After coating the catalyst layer and drying, firing was performed at 650 ° C. for 3 hours in an air atmosphere to obtain (catalyst A1) on the exhaust inflow side.
Also, H-type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 100 parts (hereinafter referred to as ZSM-5), 215 parts of silica sol (solid content 20%), 100 parts of 10% nitric acid and 15 parts of water were charged into a magnetic pot, and ZSM-5 slurry was produced in the same manner as above. Then, 150 g / L was coated on the monolith support by the same method, dried and fired at 400 ° C. for 1 hour.
100 g / L Pt / CeO on the ZSM-5 layer as above ₂ The catalyst layer was coated, dried, and calcined at 400 ° C. for 1 hour. Furthermore, Pt / CeO ₂ Rh / Al on the layer ₂ O ₃ The catalyst layer was coated at 50 g / L, dried, and then calcined at 650 ° C. for 3 hours to obtain (adsorption catalyst B1) on the exhaust outflow side.
(Tandem type adsorption catalyst-1) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B1) on the exhaust outflow side.
[0018]
(Example 2)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 100 parts, 215 parts of silica sol (solid content 20%), 100 parts of 10% nitric acid and 15 parts of water were charged into a magnetic pot to produce a ZSM-5 slurry in the same manner as in Example 1, and a monolith was produced by the same method. The carrier was coated with 150 g / L, dried, and calcined at 400 ° C. for 1 hour.
Next, alumina powder carrying Pd (hereinafter referred to as Pd / Al ₂ O ₃ 100 parts, 50 parts of alumina, 150 parts of 2% nitric acid are charged in a porcelain pot, and a washcoat slurry is produced by the same method as in Example 1, and 100 g / L of Zg-5 layer is formed on the ZSM-5 layer by the same coating method. Pd / Al ₂ O ₃ The layer was coated, dried and fired.
Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B2).
(Tandem type adsorption catalyst-2) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B2) on the exhaust outflow side.
[0019]
(Example 3)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) (hereinafter referred to as USY) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, water 15 parts were charged in a porcelain pot, and ZSM-5 and USY were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5 and USY in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B3).
(Tandem type adsorption catalyst-3) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B3) on the exhaust outflow side.
[0020]
(Example 4)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and USY was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5 and USY in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated with 50 g / L, dried and fired to obtain (Adsorption Catalyst B4).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B4) on the exhaust outflow side gave (tandem type adsorption catalyst-4).
[0021]
(Example 5)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 67 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts of silica sol (solid content 20%) 215 parts, 10 parts of nitric acid 100 parts, and 15 parts of water were charged into a porcelain pot, and a mixed slurry of ZSM-5 and USY was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5 and USY in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ Catalyst layer is Pt / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B5).
(Tandem type adsorption catalyst-5) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B5) on the exhaust outflow side.
[0022]
(Example 6)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 67 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts of silica sol (solid content 20%) 215 parts, 10 parts of nitric acid 100 parts, and 15 parts of water were charged into a porcelain pot, and a mixed slurry of ZSM-5 and USY was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5 and USY in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ Catalyst layer is Pt / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B6).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B6) on the exhaust outflow side gave (tandem type adsorption catalyst-6).
[0023]
(Example 7)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, H-type mordenite (hereinafter referred to as mordenite) (SiO ₂ / Al ₂ O ₃ = 200) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and mordenite was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5 and mordenite in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B7).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B7) on the exhaust outflow side gave (tandem type adsorption catalyst-7).
[0024]
(Example 8)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, H-type mordenite (SiO ₂ / Al ₂ O ₃ = 200) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and mordenite was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, on the mixed layer of ZSM-5 and mordenite in the same manner as in Example 1, 100 g / L of Pd / Al ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer was coated on the Pt / Al2O3 layer at 50 g / L, dried and fired to obtain (Adsorption Catalyst B8).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B8) on the exhaust outflow side gave (tandem type adsorption catalyst-8).
[0025]
Example 9
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, H-type β zeolite (hereinafter referred to as β zeolite) (SiO ₂ / Al ₂ O ₃ = 100) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and β zeolite was produced in the same manner as in Example 1. . Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / Al on the mixed layer of ZSM-5 and β zeolite in the same manner as in Example 1. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B9).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B9) on the exhaust outflow side gave (tandem type adsorption catalyst-9).
[0026]
(Example 10)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, H-type beta zeolite (SiO ₂ / Al ₂ O ₃ = 100) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and β zeolite was produced in the same manner as in Example 1. . Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5 and β zeolite in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B10).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B10) on the exhaust outflow side gave (tandem type adsorption catalyst-10).
[0027]
(Example 11)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 67 parts, H-type β zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and β zeolite was produced in the same manner as in Example 1. . Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5 and β zeolite in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B11).
(Tandem type adsorption catalyst-11) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B11) on the exhaust outflow side.
[0028]
(Example 12)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 67 parts, H-type β zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and β zeolite was produced in the same manner as in Example 1. . Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5 and β zeolite in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated with 50 g / L, dried and fired to obtain (Adsorption Catalyst B12).
(Tandem type adsorption catalyst-12) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B12) on the exhaust outflow side.
[0029]
(Example 13)
H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 100 parts, 215 parts of silica sol (solid content 20%), 100 parts of 10% nitric acid, and 15 parts of water were charged into a porcelain pot, and a USY slurry was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, a 100 g / L Pt / CeO 2 catalyst layer was coated on the USY layer in the same manner as in Example 1, dried and fired. Further, the Rh / Al 2 O 3 catalyst layer was formed into Pt / CeO by the same method as in Example 1. ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B13).
(Tandem type adsorption catalyst-13) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B13) on the exhaust outflow side.
[0030]
(Example 14)
H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 100 parts, 215 parts of silica sol (solid content 20%), 100 parts of 10% nitric acid, and 15 parts of water were charged into a porcelain pot, and a USY slurry was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the USY layer in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B14).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B14) on the exhaust outflow side gave (tandem type adsorption catalyst-14).
[0031]
(Example 15)
H-type β zeolite (SiO ₂ / Al ₂ O ₃ = 100) 100 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a β zeolite slurry was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the β zeolite layer in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, the Rh / Al 2 O 3 catalyst layer was formed into Pt / CeO by the same method as in Example 1. ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B15).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B15) on the exhaust outflow side gave (tandem type adsorption catalyst-15).
[0032]
(Example 16)
H-type β zeolite (SiO ₂ / Al ₂ O ₃ = 100) 100 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a β zeolite slurry was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the β zeolite layer in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B16).
The (tandem type adsorption catalyst-16) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B16) on the exhaust outflow side.
[0033]
(Example 17)
H-type mordenite (SiO ₂ / Al ₂ O ₃ = 200) 100 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged into a porcelain pot, and a mordenite slurry was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mordenite layer in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B17).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B17) on the exhaust outflow side gave (tandem type adsorption catalyst-17).
[0034]
(Example 18)
H-type mordenite (SiO ₂ / Al ₂ O ₃ = 200) 100 parts, 215 parts of silica sol (solid content 20%), 100 parts of 10% nitric acid and 15 parts of water were charged into a porcelain pot, and a mordenite slurry was produced in the same manner as in Example 1. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / Al on the mordenite layer in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B18).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B18) on the exhaust outflow side gave (tandem type adsorption catalyst-18).
[0035]
Example 19
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, H-type mordenite (SiO ₂ / Al ₂ O ₃ = 200) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5, USY, and mordenite was produced in the same manner as in Example 1. did. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5, USY, and mordenite in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B19).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B19) on the exhaust outflow side was combined to obtain (tandem type adsorption catalyst-19).
[0036]
(Example 20)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, H-type mordenite (SiO ₂ / Al ₂ O ₃ = 200) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5, USY, and mordenite was produced in the same manner as in Example 1. did. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5, USY, and mordenite in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated with 50 g / L, dried and fired to obtain (Adsorption Catalyst B20).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B20) on the exhaust outflow side gave (tandem type adsorption catalyst-20).
[0037]
(Example 21)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, H-type beta zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5, USY, and β zeolite was prepared in the same manner as in Example 1. Manufactured. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5, USY, and β zeolite in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B21).
The (tandem type adsorption catalyst-21) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B21) on the exhaust outflow side.
[0038]
(Example 22)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, H-type beta zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5, USY, and β zeolite was prepared in the same manner as in Example 1. Manufactured. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, on the mixed layer of ZSM-5, USY, and β zeolite in the same manner as in Example 2, 100 g / L of Pd / Al ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated with 50 g / L, dried and fired to obtain (Adsorption Catalyst B22).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B22) on the exhaust outflow side was combined to obtain (tandem type adsorption catalyst-22).
[0039]
(Example 23)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, ZSM-5 ion-exchanged Ag (hereinafter referred to as Ag-ZSM-5) (Ag loading 5 wt%, SiO ₂ / Al ₂ O ₃ = 30) 33 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, water 15 parts were charged in a porcelain pot, and ZSM-5, Ag-ZSM-5, USY were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5, Ag-ZSM-5, and USY in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated with 50 g / L, dried and fired to obtain (Adsorption Catalyst B23).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B23) on the exhaust outflow side gave (tandem type adsorption catalyst-23).
[0040]
(Example 24)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, Ag-supported ZSM-5 (Ag-supported amount 5% by weight, SiO ₂ / Al ₂ O ₃ = 30) 33 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, water 15 parts were charged in a porcelain pot, and ZSM-5, Ag-ZSM-5, USY were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5, Ag-ZSM-5, and USY in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated with 50 g / L, dried and fired to obtain (Adsorption Catalyst B24).
The (tandem type adsorption catalyst-24) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B24) on the exhaust outflow side.
[0041]
(Example 25)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, ZSM-5 ion-exchanged Pd (hereinafter referred to as Pd-ZSM-5) (Pd loading 2 wt%, SiO 2 ₂ / Al ₂ O ₃ = 30) 33 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, water 15 parts were charged in a porcelain pot, and ZSM-5, Pd-ZSM-5, USY were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, a 100 g / L Pt / CeO2 catalyst layer was coated on the mixed layer of ZSM-5, Pd-ZSM-5, and USY in the same manner as in Example 1, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B25).
The (tandem type adsorption catalyst-25) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B25) on the exhaust outflow side.
[0042]
(Example 26)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, Pd supported ZSM-5 (Pd supported amount 2 wt%, SiO 2 ₂ / Al ₂ O ₃ = 30) 33 parts, H-type USY (SiO ₂ / Al ₂ O ₃ = 50) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, water 15 parts were charged in a porcelain pot, and ZSM-5, Pd-ZSM-5, USY were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5, Pd-ZSM-5, and USY in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B26).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B26) on the exhaust outflow side gave (tandem type adsorption catalyst-26).
[0043]
(Example 27)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, Ag-supported ZSM-5 (Ag-supported amount 5% by weight, SiO ₂ / Al ₂ O ₃ = 30) 33 parts, H-type beta zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and ZSM-5, Ag-ZSM-5, β zeolite were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5, Ag-ZSM-5, and β zeolite in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B27).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B27) on the exhaust outflow side gave (tandem type adsorption catalyst-27).
[0044]
(Example 28)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, Ag-supported ZSM-5 (Ag-supported amount 5% by weight, SiO ₂ / Al ₂ O ₃ = 30) 33 parts, H-type beta zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and ZSM-5, Ag-ZSM-5, β zeolite were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, on the mixed layer of ZSM-5, Ag-ZSM-5, and β zeolite in the same manner as in Example 2, 100 g / L of Pd / Al ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B28).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B28) on the exhaust outflow side gave (tandem type adsorption catalyst-28).
[0045]
(Example 29)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, Pd supported ZSM-5 (Pd supported amount 2 wt%, SiO 2 ₂ / Al ₂ O ₃ = 30) 33 parts, H-type beta zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, water 15 parts were charged in a porcelain pot, and ZSM-5, Pd-ZSM-5, β zeolite were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, a 100 g / L Pt / CeO 2 catalyst layer was coated on the mixed layer of ZSM-5, Pd-ZSM-5, and β zeolite in the same manner as in Example 1, dried and calcined. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B29).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B29) on the exhaust outflow side gave (tandem type adsorption catalyst-29).
[0046]
(Example 30)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 34 parts, Pd supported ZSM-5 (Pd supported amount 2 wt%, SiO 2 ₂ / Al ₂ O ₃ = 30) 33 parts, H-type beta zeolite (SiO ₂ / Al ₂ O ₃ = 100) 33 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot and ZSM-5, Pd-ZSM-5, β zeolite were prepared in the same manner as in Example 1. A mixed slurry was produced. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, on the mixed layer of ZSM-5, Pd-ZSM-5, and β zeolite in the same manner as in Example 2, 100 g / L of Pd / Al ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B30).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B30) on the exhaust outflow side gave (tandem type adsorption catalyst-30).
[0047]
(Example 31)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, USY obtained by ion exchange of Ag (hereinafter referred to as Ag-USY) (Ag loading 5 wt%, SiO ₂ / Al ₂ O ₃ = 12) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and Ag-USY was produced in the same manner as in Example 1. did. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pt / CeO on the mixed layer of ZSM-5 and Ag-USY in the same manner as in Example 1. ₂ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is made of Pt / CeO ₂ The layer was coated with 50 g / L, dried and fired to obtain (Adsorption Catalyst B31).
The (tandem type adsorption catalyst-31) was obtained by combining (catalyst A1) on the exhaust inflow side and (adsorption catalyst B31) on the exhaust outflow side.
[0048]
(Example 32)
H type ZSM-5 (SiO ₂ / Al ₂ O ₃ = 700) 50 parts, Ag-USY (Ag loading 5% by weight, SiO ₂ / Al ₂ O ₃ = 12) 50 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid 100 parts, and water 15 parts were charged in a porcelain pot, and a mixed slurry of ZSM-5 and Ag-USY was produced in the same manner as in Example 1. did. Then, 150 g / L was coated on the monolith support in the same manner as in Example 1, dried and fired.
Next, 100 g / L of Pd / Al on the mixed layer of ZSM-5 and Ag-USY in the same manner as in Example 2. ₂ O ₃ The catalyst layer was coated, dried and fired. Further, Rh / Al is used in the same manner as in Example 1. ₂ O ₃ The catalyst layer is Pd / Al ₂ O ₃ The layer was coated at 50 g / L, dried and fired to obtain (Adsorption Catalyst B32).
A combination of (catalyst A1) on the exhaust inflow side and (adsorption catalyst B32) on the exhaust outflow side to obtain (tandem type adsorption catalyst-32).
[0049]
(Example 33)
In the same manner as in Example 1, Pd / CeO ₂ The layer was coated at 200 g / L, dried and fired. Furthermore, Pd / CeO in the same way ₂ The layer was coated with 50 g / L of Rh / Al 2 O 3 layer, dried, and then fired at 650 ° C. for 3 hours to obtain (Catalyst A2).
A combination of (catalyst A2) on the exhaust inflow side and (adsorption catalyst B5) on the exhaust outflow side gave (tandem type adsorption catalyst-33).
[0050]
(Example 34)
A combination of (catalyst A2) on the exhaust inflow side and (adsorption catalyst B9) on the exhaust outflow side gave (tandem type adsorption catalyst-33).
[0051]
(Comparative Example 1)
H-type USY (SiO ₂ / Al ₂ O ₃ = 50), 215 parts of silica sol (solid content 20%) 215 parts, 10 parts of nitric acid water 100 parts, and 15 parts of water were charged in a porcelain pot to produce a washcoat slurry in the same manner as in Example 1, The monolith carrier was coated with 150 g / L, dried and fired to obtain (Adsorption Catalyst B35). (Adsorption catalyst 35) on the exhaust inflow side and (catalyst A1) on the exhaust outflow side were combined to obtain (tandem type adsorption catalyst-35).
[0052]
(Comparative Example 2)
H-type USY (SiO ₂ / Al ₂ O ₃ = 7) 100 parts, silica sol (solid content 20%) 215 parts, 10% nitric acid water 100 parts, water 15 parts were charged in a porcelain pot, and a washcoat slurry was produced in the same manner as in Example 1, The monolith carrier was coated with 150 g / L, dried and fired to obtain (Adsorption Catalyst-36).
(Adsorption catalyst B36) was combined on the exhaust inflow side and (catalyst A1) was combined on the exhaust outflow side to obtain (tandem adsorption catalyst-36).
[0053]
(Comparative Example 3)
(Adsorption catalyst B13) on the exhaust inflow side and (catalyst A1) on the exhaust outflow side were combined to obtain (tandem type adsorption catalyst-37).
[0054]
[Test example]
Using the tandem type adsorption catalyst using the catalyst A and the adsorption catalyst B of Examples 1 to 34 and Comparative Examples 1 to 4, HC adsorption / purification characteristic evaluation (FTP75Abag) was made by Nissan Motor Co., Ltd. (The displacement was 3 liters). The purification characteristics of each adsorption catalyst B were compared with those of a system without an adsorption catalyst (catalyst A only).
That is, the evaluation is
(1) In order to evaluate the adsorption capacity of HC discharged at engine start, measure the emission reduction rate for Abag 0 to 125 seconds,
(2) In order to evaluate the adsorption and purification ability of HC at the time of starting the engine and after raising the temperature, the emission reduction rate for Abag 0 to 505 seconds was measured.
[0055]

[0056]
In the evaluation, as shown in FIG. 1, a catalyst having 40 g / cf of Pt / Rh supported at a ratio of Pt: Rh = 5: 1 on the exhaust manifold 2 of the engine 1 as a pre three-way catalyst 3 (0.5 L). , Exhaust gas with a durable Pt-Rh catalyst that has been engine-endured at 850 ° C for 100 hours (with combustion cut), and an adsorbed catalyst B5 (1.3L) after the underfloor three-way catalyst A4 (1.3L) Using the purifier, the performance was compared with the case where the adsorption catalyst B was not installed. The evaluation results are shown in Table 1.
[0057]
[Table 1]

[0058]
【The invention's effect】
As described above, in the exhaust gas purification method of the present invention, an adsorption layer comprising a zeolite coated with an inorganic substance containing a catalytically active component on the exhaust side and arranged on the exhaust inflow side and made of zeolite effective for HC adsorption on the support. The adsorbed catalyst coated with is disposed on the exhaust gas outflow side, so that the desorbed HC is well purified even at a temperature at which HC begins to desorb from the adsorption layer.
[Brief description of the drawings]
FIG. 1 is a system diagram of an exhaust gas purification apparatus used in a test example.
[Explanation of symbols]
1 engine
2 Exhaust manifold
3 Pre three-way catalyst
4 Catalyst A
5 Adsorption catalyst B

Claims

An exhaust gas purification method for purifying exhaust gas by sequentially passing through a pre three-way catalyst, a catalyst A and an adsorption catalyst B without using a heater,
The catalyst A is formed by coating a honeycomb carrier with a three-way catalyst that purifies hydrocarbon, carbon monoxide, and nitrogen oxide in the vicinity of the theoretical air-fuel ratio,
The above-mentioned adsorption catalyst B is an exhaust gas purification method characterized in that a honeycomb carrier is provided with a zeolite layer effective for hydrocarbon adsorption as a lower layer and a catalyst layer capable of purifying hydrocarbons as an upper layer.

The exhaust gas purification method according to claim 1, wherein the exhaust gas flowing out from the pre-three-way catalyst always flows into the catalyst A, and the exhaust gas flowing out from the catalyst A always flows into the catalyst B.

The catalyst layer of the catalyst B is a powder in which at least one precious metal selected from the group consisting of platinum, palladium and rhodium as a catalyst component is preliminarily contained in a powder mainly composed of active ceria and / or alumina. 3. The exhaust gas purification method according to claim 1, wherein the exhaust gas purification method is formed by coating on the zeolite layer.

The exhaust gas purification method according to any one of claims 1 to 3, wherein the pre-three-way catalyst is mounted at an exhaust manifold position of the engine, and the adsorption catalyst B is mounted at an underfloor position. .

The exhaust gas purification method according to any one of claims 1 to 4, wherein the catalyst A and the adsorption catalyst B are arranged in a distance range of 10 to 50 mm.

6. The zeolite according to any one of claims 1 to 5, wherein at least one selected from the group consisting of mordenite, USY, β zeolite, and ZSM-5 is used as the zeolite in the adsorption catalyst B. Exhaust gas purification method.