Patent ID: 7393809

Claim:
A catalyst for the purification of diesel engine exhaust gas comprising at least a catalytic metal and a carrier, wherein said catalytic metal is selected from a group consisting of platinum, palladium, rhodium, ruthenium, rhenium and mixtures thereof, wherein said carrier is composed of a zirconia-titania composite oxide, and either sulfuric acid or at least one additional solid acid selected from a group consisting of oxides of tungsten and oxides of molybdenum, and said zirconia-titania composite oxide has a ratio of zirconia to titania between 10:90 and 90:10 by atomic ratio; wherein said solid acid is incorporated into said zirconia-titania composite oxide by mixing a precursor of the solid acid with a precursor of the zirconia-titania composite oxide and then calcinating the resulting mixture.