Superior activity of CeO2 modified V2O5/AC catalyst for mercury removal at low temperature

Abstract

CeO2 modified V2O5/AC catalysts (V-Ce/AC) were synthesized by an ultrasound-assisted impregnation method, and were employed to remove elemental mercury (Hg0) from simulated coal combustion flue gas at low temperature (100–200 °C). The effects of several operation conditions, including the loading of CeO2, reaction temperature, the role of O2 and stability of the catalysts were all investigated, respectively. The results showed that 1 V-8Ce/AC catalysts had the highest catalytic activity with 98.3% Hg0 removal efficiency at 150 °C. There was synergistic effect on Hg0 oxidation when V2O5 and CeO2 combined. Characterization by XPS, we found that both lattice oxygen (Oα) and chemisorption oxygen (Oβ) contribute to Hg0 oxidation. Besides, the possible mechanism of Hg0 removal over the catalysts was proposed, in which the critical steps were the adsorption of Hg0 and the oxidation of Hg0 to Hg2+ by the active oxygen on catalysts surface.