Zoned catalyst for diesel applications

摘要

An oxidation catalyst composite, methods, and systems for the treatment of exhaust gas emissions from a diesel engine are described. More particularly, an oxidation catalyst composite including a zoned diesel oxidation catalyst with a first washcoat zone with a Pt/Pd ratio that is less than 3:1 and a PGM loading at least twice that of a second washcoat zone.

主权项

1. An oxidation catalyst composite for abatement of exhaust gas emissions from a diesel engine comprising:
a substrate having a length, an inlet end and an outlet end, a catalytic material on the substrate, the catalytic material including a first washcoat zone and a second washcoat zone; the first washcoat zone comprising a first washcoat layer including platinum (Pt) and palladium (Pd) platinum group metal (PGM) components and a first refractory metal oxide support, the first washcoat zone adjacent the inlet end of the substrate; and the second washcoat zone comprising a second washcoat layer including platinum and palladium PGM components and a second refractory metal oxide support, the second washcoat layer adjacent the outlet end of the substrate; and wherein the first washcoat zone has a length that is shorter than the second washcoat zone, wherein the oxidation catalyst does not include an elevated PGM loading on the inlet face of the catalyst and the first washcoat zone has a PGM loading at least twice that of the second washcoat zone, and the first washcoat zone has a Pt/Pd ratio less than 3:1.