Catalytic Promotion and Poisoning: All-Electron Local-Density-Functional Theory of CO on Ni(001) Surfaces Coadsorbed with K or S

The adsorption of CO on Ni(001) and its coadsorption with K or S as studied with our all-electron full-potential linearized-augmented-plane-wave method show that (i) K modifies the electrostatic potential in the surface layer, produces an increased occupation of the CO antibonding 2π* states, and facilitates the dissociation of CO; (ii) in contrast, S interacts more covalently with the Ni surface and neighboring CO molecules thereby deactivating the surface and inhibiting CO dissociation.