Improved photoelectrocatalytic properties of Ti-doped BiFeO3 films for water oxidation

Because of the potential application in photoelectrochemical cells for water splitting, the synthesis of BiFeO 3 (BFO) is receiving increasing attention. A simple, low-cost drop-casting route was used to synthesize Ti ions doped BiFeO 3 thin films and the effects of the Ti ions doping on their crystal structure, morphology, and photoelectrocatalytic activity had been studied. X-ray diffraction results of Ti-BFO films showed that the doping of Ti ions lead to the distortion of crystal structure. Photoelectrochemical measurements indicated that the photoelectrocatalytic activities of BFO film doped with 5 % Ti ions showed the best performance. The UV–Vis absorption spectra of Ti-BFO films showed that the absorption wavelength of BFO doped with 5 % Ti had obvious shift and the band gap decreased. From the results of Mott–Schottky (M–S) plots, we calculated the positions of valence band (VB) and conduction band (CB) for Ti-BFO film. The outcomes showed that the band gap structure of BFO samples doped with 5 % Ti had more positive CB and more negative VB. The calculated photogenic charge carrier concentrations of BFO and Ti (0.05)-BFO were 5.07 × 10 19 and 6.32 × 10 19  cm −3 , respectively. The reduced band gap and increased photogenic charge carrier concentration are the major factors contributing to the enhancement of photoelectrocatalytic performances of Ti-BFO films.