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

摘要

Provided is a technique that makes it possible to achieve a higher NO x -purifying performance after a long-term use. An exhaust gas-purifying catalyst (1) includes a substrate, and a catalytic layer (3) supported by the substrate. The catalytic layer (3) includes a support (31) made of alumina, an oxygen storage material (33), an alkaline earth metal and/or a compound of alkaline-earth metal (32) selectively supported by a surface of the support (31) and dispersed on the surface of the support (31), and a precious metal supported by the surface of the support (34). A ratio of a number of moles of the alkaline-earth metal in the catalytic layer (3) with respect to a volumetric capacity of the exhaust gas-purifying catalyst falls within a range of 0.0004 mol/L to 0.35 mol/L.