COMPOSITION A BASE D'UN OXYDE DE ZIRCONIUM, D'UN OXYDE DE TITANE OU D'UN OXYDE MIXTE DE ZIRCONIUM ET DE TITANE SUR UN SUPPORT EN SILICE, PROCEDES DE PREPARATION ET UTILISATION COMME CATALYSEUR

摘要

Catalyst compositions include finely divided nanoscale particles of at least one supported oxide, based on a zirconium oxide, a titanium oxide or a mixed zirconium/titanium oxide deposited onto a silica based support, wherein, after calcination for 4 hours at 900° C., the supported oxide is in the form of nanoscale particles deposited onto the support, the size of the particles being at most 5 nm when the at least one supported oxide is based on a zirconium oxide, being at most 10 nm when the at least one supported oxide is based on a titanium oxide and being at most 8 nm when the at least one supported oxide is based on a mixed zirconium/titanium oxide; such catalyst compositions are especially useful for the selective reduction of NOx.