Effects of S doping on electronic structures and photocatalytic properties of anatase TiO2

Abstract

The crystal structure, impurity formation energy, electronic structure and optical properties of anatase TiO2 doped with sulfur in different valence states were studied by using the plane-wave ultrasoft pseudopotential method based on first_principles. The calculations shown that the existence form of sulfur element in anatase TiO2 was related to the experimental conditions; the octahedral dipole moments were increased due to the changes of lattice parameters, bond length and charges on atoms; the band gap narrowed and the curves of light absorption red-shifted to visible-light region due to the position of conduction band downward shifting, the position of valence band upper shifting and the width of valence band broadening result from hybridizing S 3p states with O 2p states and Ti 3d states. All of these results can explain the better photocatalytic properties of S-doped anatase TiO2 in visible-light region. According to these results, the effects on electronic structures and photocatalytic properties of anatase TiO2 doping with different valence states of sulfur were compared and analyzed.