| abstract |
A diesel exhaust treatment system and method of oxidizing NO to NO 2 at low temperatures are provided. The system utilizes a platinum catalyst on a zirconia-stabilized silica support which oxidizes NO in the exhaust gas to NO 2 and uses the NO 2 in an amount sufficient to oxidize particulate trapped on a particulate filter. The catalyst is preferably pre-treated at a temperature of between about 500 to 650° C. in a NO-oxygen-nitrogen mixture to increase conversion at low temperatures. The catalyst preferably includes an additional oxide component selected from the group consisting of TiO 2 , P 2 O 5 , WO 3 , B 2 O 3 , and Al 2 O 3. or a heteropolyacid component to further increase activity at low temperatures or to decrease platinum loading at the same level of performance. |