Ce-Doped V2O5-WO3/TiO2 with Low Vanadium Loadings as SCR Catalysts and the Resistance of H2O and SO2

The promoting effect of Ce on V-W/Ti catalyst for selective catalytic reduction (SCR) of NOx by NH3 was studied. Compared with the original V-W/Ti samples, addition of Ce contributed better NH3-SCR performance. The H2O and SO2 resistance of Ce modified V-W/Ti catalyst was improved by the different impregnation sequence of Ce. The catalysts were characterized by NH3-temperature programmed desorption (NH3-TPD), X-ray photoelectron spectroscopy (XPS), and H2-temperature programmed reduction (H2-TPR) techniques. The results showed that the impregnation sequence of W and Ce influenced the NH3 adsorption capacity of the catalysts. In comparison to 0.2V-5Ce-5W/Ti and 0.2V-(5Ce5W)/Ti, 0.2V-5W-5Ce/Ti catalyst contributed better H2O and SO2 resistance, with the highest Ce3+/(Ce4+ + Ce3+) value of 36.6%. Besides, a catalytic mechanism of SCR reactions over Ce-doped V-W/Ti catalysts was proposed.