Visible light driven nanocrystal anatase TiO_2 doped by Ce from sol-gel method and its photoelectrochemical water splitting properties

摘要

Visible light driven nanocrystal anatase TiO_2 was prepared by doping rare earth element Ce through sol-gel method. UV-Vis diffusion reflectance spectrum indicated its absorption edge extended to about 550 nm, red shifting about 170 nm compared with that without doping. Ce doping TiO_2 showed obvious anodic photocurrent effect for water splitting under visible light irradiation (λ＞420 nm) in photoelectrochemical measurement with three electrodes configuration. Ce doping TiO_2 showed higher photocurrent density than that of without doping TiO_2 under full arc irradiation. Furthermore, the electronic structures for CeO_2 and TiO_2 were analyzed theoretically based on the first principle calculation. As a result, the electronic structure for Ce doping TiO_2 is proposed as the overlap and some degree of hybridization among splitting occupied Ce 4f and unoccupied Ce 4f with O 2p and Ti 3d respectively. The visible light responsive property is mainly due to the transition from O 2p hybridizing with occupied Ce 4f to unoccupied Ce 4f overlapping with Ti 3d.