Resistance to sulfidation of the catalytic reduction of NOx over Ag/Al2O3 by controlling the loadings of Ag and Ag+

SO2 strongly decreased the catalytic activities of low loading Ag/Al2O3 below 500 °C in selective catalytic reduction (SCR) of NOx by propene with or without the assistance of non-thermal plasma (NTP), which was mainly attributed to the competition between SO2 and NO. By controlling the loadings of Ag and Ag+ over alumina, the resistance of SO2 was remarkably enhanced between 400 °C and 500 °C in thermal SCR. In the NTP-assisted SCR, most of the NOx conversions were also apparently recovered from 250 °C to 500 °C.