Promotional effect of Si-doped V2O5/TiO2 for selective catalytic reduction of NOx by NH3

TiO₂ supports doped with different amounts of Si were prepared by a sol-gel method, and 1 wt% vanadia (V₂O₅) loaded on Si-doped TiO₂ was obtained by an impregnation method. The mole ratio of Si/Ti was 0.2, NOx conversion exceeds 94% at 300celsius and GHSV of 41,324 hr^-1, which is about 20% higher than pure V₂O₅/TiO₂. The catalysts were characterized by XRD, BET, TEM, FT-IR, NH₃-TPD, XPS, H₂-TPR, Raman and in situ DRIFTS. The results of FT-IR and XPS indicated that Si was doped into the TiO₂ lattice successfully and a solid solution was obtained. V₂O₅ active component could be dispersed well on the support with the increasing of surface area of the catalyst, which was confirmed by Raman and XRD results. Above all, the numbers of acid sites (especially the Bronsted-acid) and oxidation properties were enhanced for Si-doped V₂O₅/TiO₂ catalysts, which improved the deNOx catalytic activity.