Novel Pd promoted Ag/Al2O3 catalyst for the selective reduction of NOx

A novel palladium promoted Ag/Al2O3 catalyst (denoted Ag-Pd/Al2O3) has been developed for the selective catalytic reduction of NO by C3H6. The Ag-Pd/Al2O3 shows a higher NOx conversion than Ag/Al2O3, especially at the temperatures ranging from 300 to 450 °C. The addition of a small amount of Pd (0.01 wt.%) to Ag/Al2O3 is considered to be favorable for the partial oxidation of C3H6. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) suggest that the presence of Pd catalyzes the formation of enolic species which is converted from C3H6. The enolic species is very active towards NO2 and NO3−, resulting in the formation of NCO species which is the key reaction intermediate in the selective catalytic reduction of NO.