Effect of subsurface oxygen on the reactivity of the Ag(111) surface

Periodic, self-consistent, density functional theory calculations have been performed to demonstrate that subsurface oxygen (O-(sb)) dramatically increases the reactivity of the Ag(111) surface. O-(sb) greatly facilitates the dissociation of H-2, O-2, and NO and enhances the binding of H, C, N, O, O-2, CO, NO, C2H2, and C2H4 on the Ag(111) surface. This effect originates from an O-(sb)-induced upshift of the d-band center of the Ag surface and becomes more pronounced at higher O-(sb) coverage. Our findings point to the important role that near-surface impurities, such as O-(sb),O- can play in determining the thermochemistry and kinetics of elementary steps catalyzed by transition metal surfaces.