(147g) DFT Study of the Hg Oxidation Mechanism Over the V2O5-TiO2(001) Surface

We present a density functional theory study of Hg oxidation from the interaction between Hg and HCl with the V2O5(001) surface supported on TiO2(001). We investigate the intermediate products of the reaction and calculate the reaction energy barrier for each elementary reaction, taking into account several different adsorption geometries and intermediate products. We propose that Hg oxidation occurs through a Mars-van Krevelen type mechanism consisting of seven steps: adsorption and dissociation of HCl on a surface oxygen vacancy, combination of atomic chlorine with neighboring adsorbed Hg, combination of HgCl with adsorbed Cl, desorption of HgCl2, hydroxyl recombination, water desorption and dissociative oxygen adsorption. The rate-determining step in the reaction is calculated and the results are compared qualitatively to available experimental data.