Effect of SO2 on the performance of Co/MOR catalyst for the selective catalytic reduction of NO by CH4

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°C; however, this influence is not evident at a temperature above 600°C. 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.