Composition acidity increased to zirconium oxides, silicon and at least one other element selected from titanium, aluminum, tungsten, molybdenum, cerium, iron and manganese

The composition of the invention is based on zirconium oxide, silicon oxide and an oxide of another element M selected from titanium, aluminum, tungsten, molybdenum, cerium, iron and manganese and in the proportions by weight of these components: silicon oxide: 5% -30%; oxide of the element M: 1% -20%, the balance being zirconium oxide, and it also has an acidity, measured by the test methylbutynol at least 90%. This composition can be prepared by a process in which are brought together in a liquid medium a zirconium compound, a silicon compound, a compound of the element M and a basic compound whereby a precipitate is obtained; is carried out in a liquid medium ripening of the precipitate and the precipitate is separated and calcined. The composition may be used in the treatment of diesel engine exhaust gas.