Reduction of nitrogen monoxide with propene in the presence of oxygen and moisture over gold supported on metal oxides

Gold supported on several metal oxides has been prepared with high dispersion by deposition-precipitation and coprecipitation methods. These catalysts are active for the reduction of NO with C3H6 in the presence of oxygen and moisture, the reaction temperature varied depending on the kind of metal oxide support and increasing in the order of alpha-Fe2O3 similar to ZnO < MgO similar to TiO2 < Al2O3. The highest conversion to N-2 (about 70%) was obtained over Au/Al2O3 with a metal loading of 0.1-0.2 Wt.-% at 700 K. The conversion of NO to N-2 over Au/Al2O3 was not reduced, but slightly increased by the presence of water, although over Al2O3 alone it was markedly depressed. Oxygen enhanced the reduction of NO by C3H6 and NO2 reacted with C3H6 at lower temperatures than NO, indicating that NO reduction could take place through the oxidation of NO to NO2, which might then react with C3H6.