Study of surface segregation of antimony on SnO2 surfaces by computer simulation techniques

We have carried out a computational bulk and surface study of the behavior of Sb(III) and Sb(V) ions on the (110) and (001) surfaces of SnO2. In addit ion, we have also examined the behavior of the Sn(II) and oxygen vacancy co mplex in the bulk and surface. These calculations suggest that Sb(III) is a ssociated with in-plane surface oxygen species, while Sb(V) is subsumed bel ow bridging oxygen ions in a more bulk-like environment. In addition, we fi nd two possible Sn(II)/O-vacancy complex sites for the (110) surface: one i s associated with a bridging oxygen vacancy, and the most favorable arrange ment is associated with an in-plane subsurface oxygen vacancy. These calcul ations indicate not only the most favorable complex sites but also predict the surface segregation and defect energies. The theoretically derived site s are in complete agreement with the experimental data reported recently an d proposed models for sensor activity.(1,2).