EXHAUST GAS PURIFICATION CATALYST

摘要

PROBLEM TO BE SOLVED: To make efficiently removable NOx in exhaust gas by disposing a zeolite-cotalyst layer outside a CeO2 -contg. catalyst layer from a carrier. SOLUTION: An inner catalyst layer 3 and an outer catalyst layer 4 are laminated on the surface of a carrier 2 having a honeycomb structure to obtain the objective exhaust gas purification catalyst 1 for a diesel engine. The inner catalyst layer 3 present on the carrier 2 side is formed from a ceria layer consisting of ceria (CeO2 ) 5 and a binder which binds and holds the ceria 5 on the carrier 2. The outer catalyst layer 4 remoter from the carrier 2 is formed from a Pt exchanged zeolite layer consisting of a Pt exchanged zeolite obtd. by carrying Pt 7 on a zeolite 6 by ion exchange and a binder which binds and holds the Pt exchanged zeolite on the surface of the inner catalyst layer 3.