Patent ID: 7485599

Claim:
A process for producing an oxygen storage material comprising cerium oxide and at least one second oxide of a metal M 1 , the process comprising the steps of: a) mixing an aqueous solution of a cerium oxide precursor with an aqueous solution of a precursor of an oxide of a metal M 1 selected from the group consisting of an alkaline earth metal, rare earth metal, zirconium, zinc, cobalt, copper and manganese to form a mixture; b) adding a first precipitation agent to the mixture, to form an aqueous suspension containing a precipitate, wherein the cerium oxide and the oxide of the metal M 1 form Ce/M 1 mixed oxide solid solution particles, and adding to the suspension: (i) a precursor of an oxide of a metal M 2 and (ii) barium hydroxide as a second precipitation agent to deposit M 2 on Ce/M 1 mixed oxide solid solution particles: and c) separating the precipitate from the suspension, drying and calcining the precipitate.