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AssigneeUmicore AG & Co. KG
InventorsMartin Roesch, Dieter Lindner, Raoul Klingmann, Patrizia Laura, Joerg-Michael Richter, Marcus Schmidt
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A double-layer three-way catalyst is presented, which is formed from a catalytic coating applied directly to an inert honeycomb and a catalytically active coating thereon, and is suitable especially for cleaning of exhaust gases of motor vehicles with gasoline-operated internal combustion engines. The catalyst contains, in each layer, an active aluminum oxide and a cerium/zirconium mixed oxide, both of which are catalytically activated by palladium. The second layer on the gas side contains not only palladium but also rhodium, which is applied to the active aluminum oxide and the cerium/zirconium mixed oxide of the second layer in addition to the palladium. The cerium/zirconium mixed oxide of the second layer has a higher zirconium oxide content than the cerium/zirconium mixed oxide of the first layer. The catalyst is notable for exceptional activity coupled with outstanding aging stability.
A double-layer three-way catalyst on an inert catalyst support of ceramic or metal for the cleaning of the exhaust gases of internal combustion engines, characterized in that each layer contains an active aluminum oxide and a cerium/zirconium mixed oxide, which are catalytically activated with palladium, both oxide materials of the second layer additionally being catalytically activated with rhodium, and the cerium/zirconium mixed oxide of the second layer having a higher zirconium oxide content than the cerium/zirconium mixed oxide of the first layer.
Dependencies are inferred from the claim text.