Nitric oxide reduction by propene over silver/alumina and silver–gold/alumina catalysts: effect of preparation methods Original Research Article

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 N2. 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.