Catalyzed Soot Filter With Layered Design

摘要

Disclosed is a catalyzed soot filter with layered design wherein the first coating of the filter comprises an oxidation catalyst comprising platinum (Pt) and optionally palladium (Pd), wherein the second coating of the filter comprises an oxidation catalyst comprising Pd and optionally Pt, wherein the Pt concentration in the second coating is lower than the Pt concentration in the first coating, and wherein the weight ratio of Pt:Pd in the second coating is in the range of from 1:1 to 0:1; and wherein the first coating and the second coating are present on the wall flow substrate at a coating loading ratio in the range of from 0.25 to 3, calculated as ratio of the loading of the first coating (in g/inch3 (g/(2.54 cm)3)): loading of the second coating (in g/inch3 (g/(2.54 cm)3)).