Relationship between the molecular structure of V2O5/TiO2 catalysts and the reactivity of SO2 oxidation†
Abstract
The relationship between the molecular structure of V2O5/TiO2 catalysts and the reactivity of SO2 oxidation was investigated. The dispersion state and surface properties of supported vanadia over V2O5/TiO2 catalysts were studied with various experimental techniques. Isolated vanadia species were dispersed on the TiO2 surface as Ti–O–V bonds at VOx coverage far below the monolayer. Polymeric vanadia species were then formed through the V–O–V bonds as the VOx coverage increased. SO2 temperature-programmed desorption and in situ diffuse reflectance infrared Fourier transform spectroscopy were conducted to study the interaction between SO2 and V2O5/TiO2. On the V2O5/TiO2 catalysts, the turnover frequency of SO2 oxidation was almost constant with increased VOx coverage under the condition of constant temperature. VO was demonstrated to play a critical role in the SO2 adsorption and oxidation. A possible reaction mechanism was established in this study.