Effect of the V4+(3+)/V5+ ratio on the denitration activity for V2O5–WO3/TiO2 catalysts
Abstract
In this study, the V4+(3+)/V5+ valence ratio on the surface of V2O5–WO3/TiO2 catalysts was adjusted by changing the oxygen flux in the calcination process and the effect on the denitration activity was evaluated. The physicochemical properties of catalysts were characterized by X-ray diffraction (XRD), H2 temperature programmed reduction (H2-TPR), NH3in situ infrared spectroscopy (NH3-DRIFT) and N2 adsorption–desorption. The results showed that an appropriate V4+(3+)/V5+ ratio is beneficial to improve the denitration activity due to the increased acidic sites, which decreases the apparent activation energy (Ea) and ensures the electron transfer in the process of the mutual transformation of V4+(3+) and V5+. A too high or low V4+(3+)/V5+ ratio is unfavorable to the denitration activity.