Method of impregnating spheres of activated alumina for use in catalyst support with cerium

摘要

A method of impregnating spheres of activated alumina with cerium in an oxidized state. The cerium-impregnated alumina spheres are for use in catalyst supports for three-way catalysts for purification of exhaust gases of automotive engines. The method has the steps of wetting spheres of activated alumina with an aqueous solution of a cerium salt, drying the wet spheres and calcining the dried spheres in an oxidizing atmosphere. The drying is performed so as to complete the removal of water from the spheres by evaporation in a time period not longer than 10 min, preferably by subjecting the wet spheres to microwave heating and most preferably by performing the microwave heating with a forced draft. By quickly completing the drying the distribution of cerium in the individual spheres becomes very uniform, and this has the effect of improving the efficiency of three-way catalysts produced by using the cerium-impregnated spheres of activated alumina.