Adsorption and Dissociation of the HCl and Cl2Molecules on W(111) Surface: A Computational Study

Abstract

The adsorption and dissociation of Cl2 and HCl molecules on W(111) surface have been studied at the density functional theory (DFT) level in conjunction with the projector augmented wave (PAW) method. The molecular structures and surface-adsorbent interaction energies of W(111)/Cl, W(111)/H, W(111)/Cl2, and W(111)/HCl systems are predicted. In these studies, four adsorption sites, such as top (T), bridge (B), shallow (S), and deep (D) sites, of the W(111) surface are considered. It is shown that the Cl2 and HCl molecules adsorb to the W(111) surface by the end-on manner (by their Cl−Cl or H−Cl bonds perpendicular to the W surface), and their dissociative adsorptions occur without intrinsic energy barriers and are exothermic by 80.46 and 53.72 kcal/mol, for Cl2 and HCl, respectively. Molecular dynamics studies show that the dissociation of Cl2 and HCl molecules on the W(111) surface occur in asymmetric fashion: at the beginning adsorbate forms a strong bond between one of their atoms and W centers, followe...