Compositions based on zirconium oxide, titanium oxide or mixed zirconium titanium oxide on a silica support, preparation methods and use as catalysts

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.