EXHAUST GAS PURIFICATION METHOD AND EXHAUST GAS PURIFICATION CATALYST

摘要

An exhaust gas purification method and an exhaust gas purification catalyst which, even when the exhaust gas is in a oxygen-rich atmosphere, can surely exhibit a high NOx conversion. The method permits NOx in an exhaust gas in an oxygen-rich atmosphere to be converted by reduction. The catalyst comprises a carrier layer comprising mordenite, aluminum sulfate and cerium zirconium sulfate composite oxide supported on the carrier layer, and Pt further supported thereon. In a temperature region where hydrocarbon is not oxidized, it is adsorbed and held by mordenite, and the hydrocarbon released from the mordenite at the time of temperature elevation is cracked by the mordenite, aluminum sulfate, and cerium zirconium sulfate composite oxide, thus reducing NOx in the exhaust gas with the lower hydrocarbon produced by the cracking as a reducing agent.