High HC gas conversion rate and high CO gas conversion rate diesel oxidation catalyst with layered structure containing ceria composition as palladium support material

摘要

The present invention comprises a) a carrier substrate and b1) a first layer located on the carrier substrate, the first layer being a ceria-containing support in an amount of at least 45% by weight relative to the total weight of the support material. Palladium impregnated on the material, including platinum if necessary) and b2) a second layer located on the first layer (the second layer is impregnated on the metal oxide-containing support material, respectively) And a layered diesel oxidation catalyst (DOC) containing a platinum: palladium mass ratio of the first layer is smaller than a platinum: palladium mass ratio of the second layer.