Effect of Subsurface Chlorines on the Adsorption of Oxygen on Ag(110) Surface

Density functional calculations have been used to study the effect of subsurface chlorine atoms on the chemisorption of atomic oxygen on Ag 4 and Ag 10 cluster models of the Ag(110) surface. The subsurface chlorine atoms introduce an antibonding interaction between silver and the chemisorbed atomic oxygen, thus weakening the chemisorption bond strength. The presence of subsurface chlorine atoms also changes the character of the interaction between an incoming ethylene molecule and the adsorbed oxygen atom from repulsive to attractive. Both factors likely contribute to the promotion by chlorine of the ethylene expoxidation process.