Distribution of SO2 Oxidation Products in the SCR of NO over V2O5/TiO2 Catalysts at Different Temperatures

SO2 will form SO3 in the selective catalytic reduction (SCR) of NO over a V2O5/TiO2 catalyst. To reduce the total amount of SO2 oxidation products, the distribution of the sulfur-containing species at 180-400 degrees C was investigated. The results indicate that the amount of ammonium sulfate decreases, while the amount of gaseous SO3 increases with increasing temperature. The formation temperature for the small amount of oxidation products is located at 250-270 degrees C. Based on the adsorption and temperature-programmed desorption (TPD) tests, the role of O-2 in the migration of sulfur-containing species is revealed. The main pathway of SO2 oxidation is that SO2 is oxidized to form adsorbed SO3 and then desorbs to generate gaseous SO3 or reacts with NH3 to generate sulfate. There is also a little SO2 reacting with NH3 to form sulfite and then rapidly oxidized to ammonium sulfate.