Catalytic converter substrate and catalytic converter null for exhaust gas purification

摘要

PROBLEM TO BE SOLVED: To prevent poisoning by sulfur while maintaining NOX removing performance and to prevent the sintering and solid phase reaction of a catalytic noble metal and an NOX occluding material by carrying them on a catalyst carrier consisting of alumina particles and zirconia layers coating the surfaces of the particles. ;SOLUTION: A catalytic noble metal and an NOX occluding material selected from among alkali metals, alkaline earth metals and rare earth elements are carried on a catalyst carrier consisting of alumina particles and zirconia layers coating the surfaces of the particles of obtain the objective catalyst for removal of NOX, CO and hydrocarbons in exhaust gas in an atmosphere contg. oxygen in excess. The catalyst carrier is produced by carrying zirconium on alumina by precipitation, impregnation or spraying and then firing it at ≥700°C in an oxidizing atmosphere. Zirconium ray be carried on alumina by a sol-gel method using an alkoxide.;COPYRIGHT: (C)1997,JPO