First-principles study of TiO2 anatase (1 0 1) surfaces doped with N

In this study, the density functional theory (DFT) plane-wave pseudopotential method was employed to investigate TiO2 anatase (1 0 1) surfaces doped with oxygen vacancies and nitrogen atoms. The results demonstrate that the nitrogen doping is likely to reduce the bridging oxygen vacancy formation energy also the cost of substitution of oxygen atoms with nitrogen atoms is reduced in the presence of oxygen vacancies. Moreover, the nitrogen doping has little effect on the defective surface restructuring. Furthermore, by considering charge compensation, we focus on the electronic structures of the N-doped charge neutral surface. The results confirm that the mixing of N dopants induced states with original Ti 3d and O 2p valence band attributes to the band gap narrowing.