EXHAUST GAS PURIFICATION CATALYST

摘要

PROBLEM TO BE SOLVED: To provide an exhaust gas purification catalyst being capable of sufficiently exhibiting purification properties of catalytic noble metal and having high low-temperature purification performance of the catalyst.SOLUTION: An exhaust gas purification catalyst comprises a base material 1 forming a gas flow passage where exhaust gas flows through and a catalyst layer 10 formed on the base material 1. The catalyst layer 10 is constituted by: a lower catalyst layer 2 formed on a surface of the base material 1: a front stage upper catalyst layer 3 coating a surface of the lower catalyst layer 2 at an upstream side in a gas flow direction; and a rear stage upper catalyst layer 4 coating the surface of the lower catalyst layer 2 on the more downstream side in the gas flow direction than the front stage upper catalyst layer 3. The lower catalyst layer 2 supports at least one of Pd and Pt. The front stage upper catalyst layer 3 supports Pd. The rear stage upper catalyst layer 4 supports Rh. Pd supporting density of the front stage upper catalyst layer 3 is from 4.5 to 12 mass%.SELECTED DRAWING: Figure 1