EXHAUST GAS CLARIFICATION CATALYST

摘要

An exhaust gas clarification catalyst which comprises a carrier comprising composite particles having a structure composed of a core portion containing ZrO2 as a primary component and a surface portion which is formed on the surface of the core portion and contains an oxide having a basicity lower than that of ZrO2, and, carried thereon, a noble metal and an NOx occluding material. The composite particle exhibits a higher basicity in its inner portion and a lower basicity in its surface portion due to Al2O3 or TiO2 being enriched in its surface portion, which results in improved resistance to the poisoning by sulfur and improved performance capabilities for removing NOx after a high temperature durability test.