Synergistic effect of copper and vanadium species on Hg0 removal of Cu-SCR catalyst: A DFT and experimental study

Abstract

The synergistic effect of Cu and V species on the improved Hg0 removal performance of Cu-SCR catalyst was analyzed in depth by experiments and theoretical calculations based on density functional theory (DFT). Possible CuVOx/TiO2(001) surface models were constructed for Hg adsorption and oxidation calculations in the presence of O2. According to the results of partial density of states (PDOS) and charge populations, Cu transfers electrons to V through bridge O, and the strong hybridization of Cu 3d and O 2p orbitals facilitate the generation of O−. Although copper doping slightly promotes the Hg adsorption and oxidation ability of VOx species, the O− bonded with Cu provides the optimal adsorption sites and active centers. Strongly hybridized with CuO, Hg easily transfers charge to O− and generate HgO to desorb from the surface, and the oxygen vacancy thus formed can be supplemented by gaseous O2. Characterizations including Raman, fourier transform infrared spectroscopy (FTIR), H2 temperature program reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS) verifies the formation of Cu-O-V structure and the higher involvement of CuOx in Hg0 oxidation, and Hg0 temperature program desorption (Hg0-TPD) were conducted to verify the reaction mechanism. This study reveals the good potential of copper species in Hg0 removal, and provides a reference for designing new materials for mercury control.