Multilayered catalyst compositions

A layered catalyst composite comprising:

• a catalytic material on a carrier, the catalytic material comprising an inner layer deposited on the carrier comprising a palladium component on a high surface area refractory metal oxide support;
• a middle layer deposited on the inner layer comprising a platinum component on a middle layer support comprising an oxygen storage component;
• and an outer layer deposited on the middle layer comprising a rhodium component on an outer layer support comprising an oxygen storage component, wherein the catalytic material is effective to substantially simultaneously oxidize carbon monoxide and hydrocarbons and reduce nitrogen oxides.

A layered catalyst composite comprising:

• a catalytic material on a carrier, the catalytic material comprising an inner layer deposited on the carrier comprising a platinum component on an inner layer support comprising an oxygen storage component;
• a middle layer deposited on the inner layer comprising a rhodium component on both a middle layer support comprising an oxygen storage component and a middle layer high surface area refractory metal oxide support;
• and an outer layer deposited on the middle layer comprising a palladium component on both an outer layer support comprising an oxygen storage component and an outer layer high surface area refractory metal oxide support, wherein the catalytic material is effective to substantially simultaneously oxidize carbon monoxide and hydrocarbons and reduce nitrogen oxides.

A method of making a layered catalyst composite, the method comprising providing a carrier and coating the carrier with first, second, and third layers of catalytic material;

• wherein the first layer is formed by impregnating a precious metal selected from a platinum component onto a first support comprising an oxygen storage component;
• the second layer is formed by impregnating a rhodium component on a second support comprising an oxygen storage component to form a second layer;
• and the third layer is formed by impregnating a precious metal selected from a palladium component on a third support comprising a high surface area refractory metal oxide.

A method of making layered catalysts comprising barium as a stabilizer or a promoter, the method comprising depositing one or more inner coats on a substrate, preparing a slurry comprising one or more precious metal components, one or more supports, and barium tartarate, depositing the slurry on the one or more inner coats.