| 摘要 |
An oxidation catalyst for the oxidative treatment of a hydrocarbon and carbon monoxide in an exhaust gas, the oxidation catalyst comprising a supporting substrate and a plurality of catalyst layers supported on the supporting substrate, wherein the plurality of catalyst layers comprise a washcoat material , an active metal and a hydrocarbon adsorbent, and wherein one catalyst layer lies on the catalyst surface later side and one or more other layers lie on the side lower than the said one catalyst layer and wherein the amount of hydrocarbon adsorbent in the said one catalyst layer is the same as or greater than the amount in the other catalyst layer and the concentration of active metal in the said one catalyst layer is the same as or less than the concentration in the said one or more layers. Also disclosed are: a catalysed substrate monolith comprising an oxidising catalysts on a substrate monolith for use in treating exhaust gas emitted from a lean burn internal combustion engine, which catalysed substrate monolith comprising a first washcoating and a second washcoating, herein the second washcoat is disposed in a layer above the first washcoating, wherein the first washcoat comprises a catalyst composition comprising platinum and at least one support material for the platinum, wherein the second washcoat comprises a catalyst comprising both platinum and palladium and at least one support material and wherein the weight ratio of Pt to Pd in the second washcoat is ≤2; and a method of preventing the poisoning of the catalysed substrate monlith. |
