A density functional theory study of sulphur dioxide adsorption on rutile TiO2(1 1 0)

We have performed density functional theory calculations to investigate SO2 adsorption on both ideal and defective TiO2(1 1 0) surfaces. In agreement with experiments, we identify SO2-, SO3- and SO4-like adsorption complexes. We also find that adsorption on the defective surface leads to very strong bonding between the molecule and the surface. More importantly, we show that upon adsorption on the defective surface the S hybridization changes from the sp2 in the isolated molecule to the sp3 type. We demonstrate that the change is responsible for the formation of stable SO4-like species at high temperature.