Effect of SO_2 on the performance of Co/MOR catalyst for the selective catalytic reduction of NO by CH_4

The selective catalytic reduction(SCR) of NO by CH4 in the presence of SO2 was investigated over the catalyst cobalt supported on Mordenite(Co/MOR);both the fresh and spent catalysts were characterized by temperature-programmed desorption of NO(NO-TPD),X-ray diffraction(XRD),H2 temperature-programmed reduction(H2-TPR),and UV-vis diffuse reflectance spectroscopy(UV-vis DRS).The results indicated that the presence of SO2 in the feed leads to a decrease of NO conversion at a temperature below 550℃;however,this influence is not evident at a temperature above 600℃.Moreover,the negative effect of SO2 on the NO conversion is reversible over the Co/MOR catalyst.SO2 may inhibit the adsorption of NO on the active sites and promote the formation of CoO during the reaction,which leads to a decrease of the active sites and the activity of Co/MOR for the SCR of NO.