Patent attributes
An exhaust gas purifying catalyst is provided in which alloying of precious metals is prevented even at high temperatures so that degradation of catalyst can be inhibited. The exhaust gas purifying catalyst comprises a substrate serving as a passage of exhaust gas; and a catalyst coating layer formed on the internal surface of the through hole and including precious metals and a refractory inorganic oxide. The catalyst coating layer formed in the area A located on the upstream portion of the passage with respect to the flow direction of exhaust gas contains a precious metal, Rh. The weight ratio of Rh and the precious metal other than Rh is 1:0 to 0.5. The catalyst coating layer formed in the area B located on the downstream portion of the passage contains precious metal other than Rh. The weight of the precious metal other than Rh is larger than the weight of Rh.
