Nitric oxide reduction by propene over silver alumina and silver-gold/alumina catalysts: effect of preparation methods

The activities of alumina supported silver catalysts prepared by co-precipitation, impregnation and single step sol-gel methods were studied for selective NOx reduction by propene in the presence of oxygen. Catalysts prepared by the sol-gel method were found to be the most active catalysts for selective reduction of NOx with almost 100% selectivity to N-2 Catalysts prepared by the co-precipitation technique had poor activity. While the maximum activities of the sol-gel and impregnation catalysts were comparable under certain conditions, the silver loading of the sol-gel catalysts could be increased to 5% without adversely affecting activity. Increased silver loading resulted in a catalyst that was more active at higher space velocities and had a broader activity window. The sol-gel catalysts also had better performance in the presence of water vapor. (C) 1999 Elsevier Science B.V. All rights reserved.