DFT and experimental study on visible-light driven photocatalysis of rare-earth-doped TiO2

Visible-light driven photocatalysis of Rare-earth-doped TiO2 (RE-doped TiO2) was studied by means of density functional theory (DFT) and experiments. The band structure, density of states and difference electron density maps were calculated with DFT methods to predict the photocatalytic activity for RE-doped TiO2. The built-in electric field inhibiting the recombination of electrons and holes in Gd-doped TiO2 formed can be observed. Subsequently, the activities of these photocatalysts were evaluated, and the result indicated that Gd-doped TiO2 perform the highest photocatalytic activity, which was consistent with the theoretical prediction. In particular, the degradation efficiency of methylene blue (MB) exceeded 90% under a visible light of 405 nm wavelength within 10 min, when the content of Gd in Gd-doped TiO2 was 5 wt%. Consequently, the results indicated that enhanced photocatalytic activity was achieved at Gd modified TiO2 which mainly attributed to synergic-effect of suppressed recombination of charge-carriers, higher surface-area, optimum doping contents and extended towards visible-light absorption region.