Patent ID: 6514905
Filing Date: 2003-02-04
Classification: B01D,B01J,Y02A,Y02T

Abstract:
An exhaust gas purifying catalyst comprising:a refractory inorganic carrier; and a catalytic layer coated on said refractory inorganic carrier, said catalytic layer containing platinum and at least one noble metal selected from the group consisting of palladium and rhodium, and a NOx trapping substance; where platinum exists close enough to said NOx trapping substance to accept NO2 from said NOx trapping substance, which NO2 is produced according to a reaction expressed by the following chemical equation: M(NO3)2â†’2NO2+3/202+MO where M is said NOx trapping substance;wherein platinum in an amount ranging from 10 to 100% by weight of total amount of platinum in said catalytic layer is contained in a surface layer portion which lies between a surface of said catalytic layer and a depth of 0.1 mm from the surface of said catalytic layer.