AUTOMOBILE EXHAUST GAS TREATMENT CATALYST WITH RESISTANCE TO POISONING AND METHOD FOR TREATING AUTOMOBILE EXHAUST GAS

摘要

The present invention provides for novel poisoning-resistant catalysts used for automobile exhaust gas treatment systems. To alleviate the detrimental affects of engine oil and/or fuel additive poisoning the present invention provides for an overcoat layer comprising a porous refractory oxide and one or more base metal oxides, which is coated over one or more precious metal containing washcoat layers. The overcoat of the present invention prevents phosphorous as well as other poisoning deposits, from fouling and/or negatively interacting with the underlying precious metal containing washcoats. In an alternative embodiment, the present invention provides for the coating of the upstream end of a catalytic member by the overcoat layer, thereby creating an upstream poison capture zone.