Patent ID: 6165430
Filing Date: 2000-12-26
Classification: B01D,B01J,Y02T

Abstract:
A method for treating diesel engine exhaust gases containing hydrocarbons, carbon monoxide, and nitrogen oxides (NOx), the steps comprising:locating in the exhaust gas passage of a diesel engine a catalyst comprising:(a) a composite oxide of silica-alumina support material comprising: (i) 5-40 wt. % silica based on the total of silica and alumina and (ii) made by sol-gel techniques from a mixture of an alumina sol and a silica sol; and(b) 0.25 to 4 wt. % platinum carried on the silica-alumina support material; andexposing said exhaust gas to said catalyst in an oxidizing atmosphere at 200-250.degree. C., whereby over 50% of the nitrogen oxides are converted to non-polluting gases.