Research of the synergistic effects in Cu/N co-doped TiO2 surface：A DFT calculation

First principles density functional theory calculations are carried out to investigate the interactions between implanted copper and nitrogen atoms at the anatase TiO2 (001) surface. The doped configurations and formation energies of Cu on TiO2 (001) and TiO2 (101) surfaces, N on TiO2 (001) and Cu/TiO2 (001) surfaces have been considered, and the perfected structures are obtained. Compared with the S/TiO2 (001) perfected structure, the analyses of the band structure and density of states of Cu/N-TiO2 (001) show that the band gap is decreased obviously when the CuO2 state occurrs; this could improve the photocatalytic activity significantly.