Auto exhaust gas catalyst, and process for production thereof

A process for producing an auto exhaust gas catalyst capable of simultaneously removing hydrocarbons, carbon monoxide and nitrogen oxides, said catalyst consisting essentially of cerium, rhodium and platinum, and optionally, at least one additional element selected from the group consisting of iron, lanthanum, palladium and phosphorus, said process comprising first, simultaneously, depositing on a refractory inorganic support 0.5 to 30 g of cerium, 0 to 20 g of iron and 0 to 10 g of lanthanum, as elements, per liter of the finished catalyst, and thereafter depositing thereon, in any desired sequence, 0.005 to 0.3 g of rhodium, 0.05 to 3.0 g of platinum, 0 to 1.2 g of palladium and 0 to 0.5 g of phosphorus as elements, per liter of the finished catalyst, thereby causing rhodium to be present mainly on the surface layer of the catalyst.