The effect of electronegative difference on the electronic structure and visible light photocatalytic activity of N-doped anatase TiO2 by first-principles calculations

The effect of electronegative difference between nitrogen and oxygen on electronic properties of N-doped anatase TiO2 has been studied using first-principles calculations. The results indicate that the valence band maximum (VBM) shifts to high energy by 0.27 eV and the band gap states composed of N 2p, O 2p, and Ti 3d states are formed through the three states entering into the gap after N doping. The interactions of three states widen and delocalize the band gap states. The raised VBM and the wide band gap states can improve the visible light photocatalytic activity.