COMPOSITION BASED ON CERIC OXIDE, PREPARATION AND USE THEREOF

PURPOSE: To improve the oxygen storage capacity by making the composition contain CeO2 and at least one oxide of a metallic element M selected from among Fe, Bi, Ni, Sn and Cr or one of their mixtures. CONSTITUTION: 0.1-4 N aq. soln. of Ce(IV) salt such as Ce(NO3)4 and a base such as NH3 aq. soln. are mixed and neutralized at 0-60°C to prepare a colloidal dispersion of Ce(OH)4. The dispersion is heat-treated in an autoclave at temperatures of 80-300°C for 2-48 hours. After cooling the formed precipitates are filtered, washed to obtain Ce(OH)4. Subsequently Ce(OH)4 is impregnated in a soluble salt soln. of one or more than two of metallic elements M, selected from Fe, Bi, Sn, Ni and Cr to form a composition with 1-50% atomic ratio of metal M to Ce. The composition is dried at temperatures of 80-300°C and calcined at temperatures of 400-1,200°C to obtain CeO2 composition having large oxygen storage capacity. A noble metal catalyst is impregnated and mixed to the porous support, which is formed ...