Tungsten Oxide Modified V2O5-Sb2O3/TiO2 Monolithic Catalyst: NH3-SCR Activity and Sulfur Resistance

In this study, a V2O5-Sb2O3/TiO2 monolithic catalyst was modified by introducing WO3. The WO3-modified catalyst exhibited enhanced catalytic activity in the measuring temperature range of 175-320 degrees C. The changes in dispersion of vanadia species were investigated by ultraviolet-visible (UV-Vis) spectroscopy and H-2 temperature-programmed reduction (H-2-TPR). A durability test was conducted in a wet SO2-containing atmosphere at 220 degrees C for 25 h. The sulfate deposition was estimated by temperature-programmed decomposition (TPDC) of sulfates, thermo-gravimetric (TG) analysis, and temperature-programmed desorption (TPD) of NH3. Isothermal SO2 oxidation and temperature-programmed surface reaction (TPSR) of NH4HSO4 with NO were performed. Based on these characterizations, effects of WO3 modification on the sulfate tolerance of the catalyst were explored.