CATALYST FOR EXHAUST GAS PURIFICATION

摘要

A catalyst of a two-layer structure which is composed of a lower catalyst coating layer (2) comprising catalyst particles each comprising a support comprising a cerium/zirconium composite oxide and palladium deposited on the support and an upper catalyst coating layer (3) comprising catalyst particles each comprising a support made of at least either of zirconia and a cerium/zirconium composite oxide and rhodium deposited on the support. The deposition of palladium on the cerium/zirconium composite oxide enables PdO, which has higher activity, to be yielded from the palladium due to the ability to absorb/release oxygen. Thus, high oxidative activity comparable to that of platinum is produced. The support made of at least either of zirconia and a cerium/zirconium composite oxide has excellent heat resistance, and the rhodium deposited thereon is inhibited from undergoing particle growth.