COMPOSITION BASED ON ZIRCONIUM, CERIUM AND YTTRIUM OXIDES WITH HIGH REDUCTIVITY, PROCESSES FOR PREPARATION AND USE IN CATALYSIS

摘要

The composition of the invention is based on oxides of zirconium, cerium and yttrium with a proportion of cerium oxide of between 3% and 15% and proportions of yttrium oxide which satisfy the following conditions: plus 6% if the proportion of cerium oxide is between 12% excluded and 15% inclusive; not more than 10% if the proportion of cerium oxide is between 7% excluded and 12% inclusive; not more than 30% if the proportion of cerium oxide is between 3 and 7% inclusive; the complement in zirconium oxide. The composition may also optionally comprise an oxide of a rare earth chosen from lanthanum, neodymium and praseodymium. The composition can be used for the treatment of automobile exhaust.