EXHAUST GAS PURIFYING CATALYST, POWDER MATERIAL, AND METHOD FOR PRODUCING EXHAUST GAS PURIFYING CATALYST

摘要

Disclosed is a technique which is advantageous for improving the NOx removing performance after long-term use. Specifically disclosed is an exhaust gas purifying catalyst (1) which comprises a base and a catalyst layer (3) that is supported by the base. The catalyst layer (3) comprises a carrier (31) that is formed from alumina, an oxygen storage material (33), an alkaline earth metal and/or an alkaline earth metal compound (32) that is selectively supported by the surface of the carrier (31) and dispersed on the surface of the carrier (31), and a noble metal (34) that is supported by the surface of the carrier (31). The ratio of the mole number of the alkaline earth metal in the catalyst layer (3) to the volume of the exhaust gas purifying catalyst is within the range from 0.0004 mol/L to 0.35 mol/L.