CATALYST FOR PURIFYING EXHAUST GAS

PURPOSE:To improve a ternary catalyst using palladium as a catalyst component and to further enhance NOx removing capacity in an atmosphere slightly lean as compared with a stoichiometric atmosphere. CONSTITUTION:The catalyst for purifying exhaust gas is constituted of a carrier base material, the catalyst supporting layer applied and formed to the surface of the carrier base material and the catalytically active component consisting of palladium, platinum and alkaline earth metal supported on the catalyst supporting layer and characterized by that platinum is supported on the upstream side with respect to an exhaust gas flowing direction. By supporting platinum having a characteristic excellent in purifying capacity under a condition large in the amplitude of fluctuation of an air/fuel ratio (A/F) on the upstream side, the balance between the characteristic of palladium excellent in ternary activity in the vicinity of stoichiometry and the characteristic of platinum excellent in NOx removing capacity on a lean atmosphere side becomes optimum and NOx removing capacity in an atmosphere slightly lean as compared with a stoichiometric atmosphere is enhanced.