Exhaust gas purifying catalyst and method of producing same

摘要

An exhaust gas purifying catalyst for exhaust gas discharged from a lean-burn engine of an automotive vehicle. The catalyst comprises a refractory inorganic carrier. A catalytic layer is coated on the refractory inorganic carrier. The exhaust gas purifying catalyst layer contains platinum and at least one noble metal selected from the group consisting of palladium and rhodium, and a NOx trapping substance. In the catalytic layer, platinum exists close enough to the NOx trapping substance to accept NO2 from the NOx trapping substance which NO2 is produced according to reaction expressed by the following chemical equation: M(NO3)2 -> 2NO2 + 3/2O2 + MO where M is the NOx trapping substance.