Abstract: The invention provides a carrier-supported catalyst, wherein alumina partially converted to .alpha.-Al.sub.2 O.sub.3 is the carrier having between 0.2 and 10 weight % of cerium in oxide form deposited thereon as the catalytically active ingredient.The carrier supported catalyst is made by compressing hydrous alumina or unstable anhydrous alumina into shapes. The shapes are annealed for 10-20 hours at 1000.degree.-1250.degree. C. The annealed shapes are impregnated with an aqueous solution of a cerium salt of a readily decomposable acid and dried at 130.degree.-150.degree. C. The dry cerium salt is decomposed by gradually heating the shapes at 20.degree.-300.degree. C and 450.degree.-550.degree. C, respectively, and the resulting cerium oxide-containing shapes are annealed at 700.degree.-900.degree. C.