EXHAUST GAS PURIFICATION CATALYST

摘要

The exhaust gas purification catalyst disclosed herein is provided with a substrate 10 and a catalyst coating layer 30 that is formed on the surface of the substrate 10. The catalyst coating layer 30 is formed into a layered structure having upper and lower layers, with a lower layer 50 being closer to the surface of the substrate 10 and an upper layer 40 being relatively farther therefrom. The catalyst coating layer 30 is provided with Rh and Pd as precious metal catalysts and is provided with an OSC material having an oxygen storage capacity as a support. The Rh is disposed in the upper layer 40 of the catalyst coating layer 30, and the Pd is disposed in both the upper layer 40 and the lower layer 50 of the catalyst coating layer 30. At least a portion of the Pd in the upper layer 40 and in the lower layer 50 is supported on the OSC material. The mass ratio of the Pd disposed in the upper layer 40 to the Pd disposed in the lower layer 50 is not more than 0.4.