CERIUM OXIDE AND ZIRCONIUM OXIDE COMPOUNDS WITH ELEVATED REDUCIBILITY AND SURFACES, PREPARATION PROCESSES AND USE AS A CATALYST

摘要

The composition of the invention is based on cerium oxide and zirconium oxide in an atomic proportion this / zr of at least 1, it has a degree of reducibility of at least 70% and a surface of at least 15 m2 / g. it is obtained by a process in which is a mixture comprising the compounds of cerium and zirconium; this mixture is brought into contact with a basic compound, whereby a precipitate is obtained that is heated in an aqueous medium; it is added to this medium or to the separated precipitate an additive of the type of surfactant or a polyethylene - glycols or a carboxylic acid; the mixture is ground and then calcining the precipitate thus obtained in an inert gas atmosphere or under vacuum, in a first time, at a temperature of at least 850 ~ c. and then in an oxidizing atmosphere, in a second time, at a temperature of at least 400 ~ c.