Density functional theory study of mercury adsorption on V2O5 (001) surface with implications for oxidation

The installation of selective catalytic reduction (SCR) system for reduction of NOx can prompt the oxidation and removal of elemental mercury. Understanding the mechanism behind Hg oxidation via SCR catalysts will broaden the applicability of SCR system in Hg removal strategies. This research investigated the bindings of Hg-0, HCl, HgCl and HgCl2 to the V2O5 (0 0 1) surface using density functional theory (DFT) method. The V2O5 (0 0 1) surface was represented by a periodic model, and different adsorption sites were considered. Adsorption energies and geometries of Hg-0, HCl, HgCl and HgCl2 on the V2O5 surface were calculated. The results indicated that Hg-0 adsorption on V2O5 surface is stronger than that of HCl. The adsorptions of HgCl and HgCl2 on V2O5 surface are mainly chemisorption. The adsorption energy of HgCl on V2O5 surface is stronger than that of HgCl2, which means that HgCl-surface is an important intermediate for mercury oxidation. The chlorine species has a strong influence on mercury adsorption as well as mercury oxidation, which is compatible with the available experimental results. The oxidation pathway for V2O5-catalyzed Hg oxidation by chlorine species was also presented. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.