Effects of 4d transition metals doping on the photocatalytic activities of anatase TiO₂ (101) surface

Aiming at improving the visible-light photocatalytic activities of TiO₂(101) surface we make an in-depth study on the TiO₂(101) doped with 4d transition metal (TM) atoms. It is shown that the 4d TM dopings can not only produce new impurity energy bands in the band gap but also result in the semiconductor–metal phase transition. Consequently, the visible-light absorption is strongly strengthened due to the dopings of Y, Zr, Nb, Mo, and Ag, while it is only weakly improved for Tc, Ru, Rh, Pd, and Cd dopings. The improvement in visible-light absorption can be attributed to the intraband or interband transition of electrons. Moreover, the photocatalytic activities are explored, and we find Y and Ag dopings can effectively enhance the photocatalytic activity of TiO₂(101) surface. Thus the mechanism of improving photocatalytic activity of TiO₂(101) has been clearly addressed, which is beneficial to further experimental and theoretical researches on TiO₂ photocatalysts.