First-principles study on transition metal-doped anatase TiO ₂

Abstract

The electronic structures, formation energies, and band edge positions of anatase TiO ₂ doped with transition metals have been analyzed by ab initio band calculations based on the density functional theory with the planewave ultrasoft pseudopotential method. The model structures of transition metal-doped TiO ₂ were constructed by using the 24-atom 2 × 1 × 1 supercell of anatase TiO ₂ with one Ti atom replaced by a transition metal atom. The results indicate that most transition metal doping can narrow the band gap of TiO ₂, lead to the improvement in the photoreactivity of TiO ₂, and simultaneously maintain strong redox potential. Under O-rich growth condition, the preparation of Co-, Cr-, and Ni-doped TiO ₂ becomes relatively easy in the experiment due to their negative impurity formation energies, which suggests that these doping systems are easy to obtain and with good stability. The theoretical calculations could provide meaningful guides to develop more active photocatalysts with visible light response.