Exhaust gas purification catalyst and exhaust gas purification system using the exhaust gas purification catalyst

Abstract

An exhaust gas purification catalyst comprises a substrate and a catalyst layer on the substrate, and has a first section upstream along a flow direction of the exhaust gas and a second section downstream from the first section. The catalyst layer in the first section comprises a first catalyst layer comprising palladium and a second catalyst layer comprising rhodium and covering the first catalyst layer. A pore volume proportion, which is a proportion of a total volume of the pores having a pore diameter of 0.06-30.0 μm as measured by mercury press-in method and existing in the substrate and the catalyst layer in the first section to a volume of a entire first section, is 12-18%. A wash coat amount, which is a mass per unit volume of the catalyst layer in the first section to the volume of the substrate existing in the first section, is 100-190 g/L.