Patent attributes
An exhaust gas purifying catalyst exhibiting high purification performance in the Hot range is provided. The exhaust gas purifying catalyst has a catalyst substrate and a catalyst coating layer formed on the catalyst substrate. The catalyst coating layer has a layered structure including an inside layer a containing the component (a-1) and the component (a-2) described below, and an outside layer b containing the component (b-1) and the component (b-2) described below. Component (a-1) and component (b-1): noble metals. Component (a-2): a compound oxide of (i) Ce, (ii) Zr and (iii) an element selected from the group consisting of rare earth elements, alkaline earth elements and Y, having a ratio of (ii) to (i) within the range of more than 40/100 but not more than 100/2 in terms of the weight ratio between CeO2 and ZrO2. Component (b-2): a compound oxide of elements including at least (v) and (vi) selected among (iv) Ce, (v) Zr and (vi) an element selected from the group consisting of rare earth elements, alkaline earth elements and Y, having a ratio of (v) to (iv) of not more than 40/100 in terms of the weight ratio between CeO2 and ZrO2.
