FT-IR study of the SO2 oxidation behavior in the selective catalytic reduction of NO with NH3 over commercial catalysts

The catalytic oxidation process of SO2 and the effects of NH3, NO and O2 on its oxidation behavior was investigated with FT-IR spectroscopy. It was found that the SO2 oxidation occurred via the following steps. SO2 first absorbed on V2O5 and occupied at O position to form SO32−. Then, it reacted with V5+-OH to generate VOSO4-like intermediate species, which was promoted to transform into SO3 and V2O5 by re-oxidizing V4+ to V5+ by O2. The oxidation of SO2 was suppressed in the presence of NH3 and NO due to their competitive absorption on the V2O5. This indicates that removal of NOx and oxidation of SO2 are contradictory.