NOX reduction by urea under lean conditions over single step sol-gel Pt/alumina catalyst

prepared 2% Pt on alumina catalyst using a single step sol-gel process (designated as 2% Pt-SG) and tested its activity for NO,, reduction with aqueous urea solutions under oxidizing conditions. Our results show that similar to99% NO., conversion was obtained as low as 150 degreesC but above 350 degreesC, the conversion became negative because of the additional formation of NO and NO2 from the oxidation of nitrogen-containing compounds. We also found that NO, conversion activity of 2% Pt-SG is strongly dependent on water content rather than on area amount and the presence of 7% oxygen in the feed lowers the maximum NO, conversion temperature from 250 to 150degreesC. (C) 2002 Elsevier Science B.V. All rights reserved.