Catalyst composition containing segregated platinum and rhodium components

A catalyst composition comprising a carrier on which is disposed a catalytic material, the catalytic material comprising:

• a first coat carried on the carrier and comprising a first activated alumina support, a catalytically effective amount of a first platinum catalytic component dispersed on the first alumina support, a catalytically effective amount of bulk ceria and of bulk iron oxide, a catalytically effective amount of bulk nickel oxide, and baria and zirconia dispersed throughout the first coat in an amount sufficient to stabilize the alumina and the other bulk metal oxides against thermal degradation;
• and
• a second coat comprising a topcoat overlying the first coat and carried by the carrier, and comprising a co-formed rare earth oxide-zirconia support, a catalytically effective amount of a first rhodium catalytic component dispersed on the co-formed rare earth oxide-zirconia support, and a second activated alumina support having a catalytically effective amount of a second platinum catalytic component dispersed thereon, and zirconia dispersed throughout the second coat in an amount sufficient to stabilize the activated alumina support therein against thermal degradation.

A catalyst composition comprising a carrier on which is disposed a catalytic material, the catalytic material comprising:

• a first coat carried on the carrier and comprising a first activated alumina support, a catalytically effective amount of a first platinum catalytic component dispersed on the first alumina support, and a catalytically effective amount of bulk ceria;
• and a second coat carried by the carrier and comprising a co-formed yttria-zirconia support, a catalytically effective amount of a first rhodium catalytic component dispersed on the co-formed zirconia support, a second activated alumina support, and a catalytically effectively amount of a second platinum catalytic compound dispersed on the second alumina support.