PGM CATALYST COUPLED WITH A NON-PGM CATALYST WITH HC OXIDATION CAPABILITY

摘要

The present invention relates to a diesel oxidation catalyst comprising a substrate and a wash-coat comprising a first layer and a second layer, wherein the substrate has a substrate length, a front end and a rear end, the washcoat comprising the first layer comprising a first metal oxide and comprising a platinum group metal supported on a metal oxide support material; the second layer comprising a second metal oxide and comprising one or more of an oxidic compound of vanadium, an oxidic compound of tungsten and a zeolitic material comprising one or more of Fe and Cu; wherein the first layer is at least partially disposed directly on the substrate, or is at least partially disposed directly on an intermediate layer which is disposed directly on the substrate over the entire length of the substrate, on x % of the length of the substrate from the front end of the substrate, and wherein the second layer is at least partially disposed directly on the substrate, or is at least partially disposed directly on the intermediate layer which is disposed directly on the substrate over the entire length of the substrate, on y % of the length of the substrate from the rear end of the substrate, wherein x is in the range of from 25 to 75 and y is in the range of from 25 to 75 and wherein x+y is in the range of from 95 to 105, wherein the intermediate layer comprises alumina.