Abstract
Mechanism of CeO2 modified V2O5–WO3/TiO2 catalysts for elemental mercury oxidation. [Display omitted]
•Nano-sized TiO2–CeO2 mixed oxides is used as support material for Hg0 oxidation.•The Hg0 oxidation activity of VWTi was promoted by support modification.•There was synergistic effect between V2O5 and CeO2 on Hg0 oxidation.•Hg0 oxidation over V0.80WTiCe0.25 follows a Mars–Maessen mechanism.
In order to enhance the catalytic activity for elemental mercury (Hg0) oxidation without the aid of HCl, CeO2 was added into the support to modify V2O5–WO3/TiO2 catalysts. The performance of V2O5–WO3/TiO2–CeO2 (VWTiCe) catalysts on Hg0 oxidation as well as the catalytic mechanism was also studied. The catalysts were characterized by BET, XRD and XPS techniques. The results showed that the performance on Hg0 oxidation was promoted by the introduction of CeO2. NO and SO2 has a promoting effect on Hg0 oxidation in the presence of O2. Besides, the inhibitive effect of NH3 on Hg0 oxidation was confirmed by NH3 consuming the surface oxygen of catalyst. The addition of CeO2 improved the ability to resist H2O. Results also indicated that the Hg0 oxidation efficiencies of V0.80WTiCe0.25 catalysts were thought to be aided by synergistic effect between V2O5 and CeO2. Hg0 oxidation over V0.80WTiCe0.25 follows a Mars–Maessen mechanism where lattice oxygen of V2O5 reacts with adjacently absorbed Hg0.