Platinum, rhodium, and palladium catalyst for automotive emission control

Abstract From the Canadian patent

A three-way layered catalyst for use in a stoichiometric air/fuel ratio system comprising an alumina support having deposited thereon the catalyst materials platinum, palladium and rhodium and having a first layer of platinum positioned at the support surface, a second layer of catalyst material selected from the group consisting of rhodium and a mixture of palladium and rhodium adjacent to and radially inward of the first layer with palladium inward of and adjacent to said second layer where the catalyst material of such layer is rhodium. Cerium oxide may be added to the support for improved performance.