Umicore Ag & Co. Kg

Marcus Schmidt

Joerg-Michael Richter

Martin Roesch

Jan Schoenhaber

Dieter Lindner

Joel Despres

Raoul Klingmann

Nicole Schichtel

Carolin Braun

Stephanie Spiess

Frank Adam

Anke Wolf

Dieter Linder

Patrizia Laura De Cola

Jörg-Michael Richter

Martin Rösch

Patrizia Decola

The present invention relates to a catalyst comprising two layers on an inert catalyst carrier, a layer A containing at least palladium as a platinum group metal, in addition to a cerium/zirconium/lanthanum/yttrium mixed oxide, and a layer B, which is applied to layer A, containing at least rhodium as the platinum group metal, in addition to a cerium/zirconium/lanthanum/yttrium mixed oxide.

Double-layer three-way catalyst with further improved ageing stability

The present invention relates to a catalyst comprising two layers on an inert catalyst carrier, wherein a layer A lying directly on the catalyst carrier contains at least one platinum group metal and one cerium/zirconium/SE mixed oxide, and a layer B, applied on layer A and in direct contact with the flow of exhaust gas, contains at least one platinum group metal and a cerium/zirconium/SE mixed oxide, wherein SE stands for a rare earth metal other than from cerium, characterized in that the fraction of SE oxide in the cerium/zirconium/SE mixed oxide of layer A is less than the fraction of SE oxide in the cerium/zirconium/SE mixed oxide of layer B.

Double-layer three-way catalyst with improved aging stability

The present invention is directed to a catalyst system for the reduction of the harmful exhaust-gas constituents hydrocarbons (THC), carbon monoxide (CO), nitrogen oxides (NO), and the environmentally detrimental secondary emissions ammonia (NH) and nitrous oxide (NO) of combustion engines operated using gasoline and to a corresponding method for exhaust-gas purification. The system is characterized by a particular arrangement of catalysts and is used in the case of engines which are operated with predominantly, on average, stoichiometric air/fuel mixtures. Here, a three-way catalyst produced in accordance with the current prior art is preferably installed in a close-coupled position. In the underfloor position, there is situated an SCR catalyst produced in accordance with the current prior art, followed by a further three-way catalyst produced in accordance with the current prior art. The three-way catalyst in the underfloor region furthermore has a lower oxygen-storing capacity than the close-coupled three-way catalyst.

Catalyst system for gasoline combustion engines, having three-way catalysts and SCR catalyst

The present invention describes a three-way-catalyst system comprising a first three-way catalyst on an inert catalyst support which is a double-layer catalyst comprising a first layer on the inert catalyst support, comprising active alumina, a cerium/zirconium mixed oxide and palladium and a second layer applied to the first layer and in direct contact with the exhaust gas to be purified, comprising active alumina and rhodium and being free of cerium and cerium containing materials and a second three-way-catalyst located upstream of the first three-way catalyst.

Three-way-catalyst system

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.

Two-layer-three-way catalyst

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Ginsheim, Germany

Marcus Schmidt