Adsorption of V on a hematite (0 0 0 1) surface and its oxidation: Monolayer coverage

The adsorption of a monolayer of V on idealized Fe- and oxygen-terminated hematite (0 0 0 1) surfaces and subsequent oxidation under atomic O adsorption are studied by density functional theory. Theoretical results are compared with X-ray surface standing wave and X-ray photoelectron spectroscopic measurements, and interpreted in the light of data on sub-monolayer coverages. Near-surface Fe reduction under V adsorption and accompanying structural relaxation are examined. These effects and subsequent response to oxidation, are found to be highly site specific. A full monolayer of oxygen leads to a V5+ state and reoxidation of subsurface Fe to the trivalent state, seen in both theory and experiment.