COMPOSITION BASED ON OXIDES OF CERIUM, OF ZIRCONIUM AND OF ANOTHER RARE EARTH METAL WITH HIGH REDUCIBILITY, PREPARATION PROCESS AND USE IN THE FIELD OF CATALYSIS

摘要

The composition of the invention is based on oxides of cerium, of zirconium and of at least one rare earth metal other than cerium, with a cerium oxide content of greater than 50% by weight and it has, after calcination at 1000° C. for 4 hours, a specific surface area of at least 20 m2/g and an amount of mobile oxygen between 200° C. and 400° C. of at least 0.8 ml O2/g. It is prepared by a process in which, in a reactor, a mixture of compounds of cerium, of zirconium and of the other rare earth metal is reacted continuously with a basic compound with a residence time of the reaction medium in the mixing zone of the reactor of at most 100 milliseconds; the precipitate is heated then brought into contact with a surfactant before being calcined.