Exhaust gas purification catalyst

Abstract

Provided is an exhaust gas purification catalyst having a catalyst performance and an OSC performance in a compatible manner in an air-fuel ratio (A/F) rich atmosphere where HC poisoning is likely to occur. The exhaust gas purification catalyst includes a substrate and a catalyst coating layer coated on the substrate. The catalyst coating layer includes a first catalyst coating layer containing Pd and/or Pt as a catalyst metal and a second catalyst coating layer containing Rh as a catalyst metal. The first catalyst coating layer is formed from an end portion in an upstream side with respect to an exhaust gas flow direction in the exhaust gas purification catalyst. The second catalyst coating layer includes a high specific surface area OSC material having a specific surface area of more than 40 m2/g, a medium specific surface area OSC material having a specific surface area of 4 m2/g to 40 m2/g, and a low specific surface area OSC material having a specific surface area of less than 4 m2/g.

Dependencies are inferred from the claim text.