Effect of halogen atoms (Cl, Br, I) on the structure and catalytic behavior of Ag(111) surface: a density functional theory study

A comparative study on the effects of different halogen atoms (Cl, Br, I) on the structure and catalytic behavior of Ag(111) has been performed with a series of cluster calculations using the density functional theory method. The results of calculations show that the atomic adsorption energies of halogen and oxygen atoms on the Ag(111) surface are in the order O>Cl>Br>I regardless of the relaxation of the surface. However, iodine atoms show the greatest effect on the structure of Ag(111) surface compared with the other halogen atoms (Cl, Br). Based on the results of calculations, the promoting effects of the halogen atoms on the two oxidation reactions catalyzed by silver, i.e. the epoxidation of ethylene and the partial oxidation of methanol, have been discussed.