Promotional effect of CeO2 modified support on V2O5-WO3/TiO2 catalyst for elemental mercury oxidation in simulated coal-fired flue gas

摘要

In order to enhance the catalytic activity for elemental mercury (Hg-0) 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 Hg-0 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 Hg-0 oxidation was promoted by the introduction of CeO2. NO and SO2 has a promoting effect on Hg-0 oxidation in the presence of O-2. Besides, the inhibitive effect of NH3 on Hg-0 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 Hg-0 oxidation efficiencies of V0.80WTiCe0.25 catalysts were thought to be aided by synergistic effect between V2O5 and CeO2. Hg-0 oxidation over V0.80WTiCe0.25 follows a Mars-Maessen mechanism where lattice oxygen of V2O5 reacts with adjacently absorbed Hg-0. (C) 2015 Elsevier Ltd. All rights reserved.