| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of sulfates by depositing a catalyst metal more in the upstream side than in the downstream side and depositing an oxygen storage metal only on the upstream side in a catalyst produced by depositing the catalyst metal on a catalyst carrier layer formed on the surface of fine pores of a porous catalyst carrier. SOLUTION: A honeycomb filter, which is a monolith type carrier, is used as a porous catalyst carrier 2 in an exhaust gas purifying catalyst 1 of a diesel engine and a catalyst carrier layer is formed on the surface of the fine pores of the porous catalyst carrier 2 and a catalyst metal is deposited on the catalyst carrier layer. As the catalyst carrier layer, alumina, titania, etc., are used and as the catalyst metal, platinum, rhodium, palladium, etc., are used. In this case, the catalyst metal is deposited more in the downstream side than in the upstream side in the exhaust gas flow direction of the exhaust gas purifying catalyst 1 and moreover, an oxygen storage metal is deposited only in the upstream side. Consequently, oxidation of SO2 is suppressed and sulfates formation is prevented. |
