First principle study of CuN, Cu and N-doped anatase TiO2

•CuN, Cu and N-doped anatase TiO2 are studied by using DFT.•The Cu interstitial and N substitutional co-doped TiO2 are most favorable structure.•The band gap is the smallest in V region after CuN co-doped TiO2.•The activity of CuN co-doped is highest than that of corresponding single atom doped.

Cu, N and CuN-doped anatase TiO2 are studied using density functional theory (DFT). It is found the band gap decreases after CuN co-doped. The intensity of adsorption spectra increases in the following order: CuN codoped⪢Cu-doped⪢N-doped⪢pure anatase in visible region, indicating that the electrons on the valence band easily transit to the conduction band. In other words, theoretic calculation shows that the photocatalytic activity of CuN co-doped is higher than that of the corresponding single Cu or N-doped.