Optical band structure and photogenerated carriers transfer dynamics in FTO/TiO2 heterojunction photocatalysts

The FTO/TiO2 heterojunction photocatalysts were prepared and characterized by XRD, SEM, UV–vis and electrochemical impedance measurement. The effect of F doping level on the optical band gap and conductivity of as-prepared FTO samples, as well as the band alignment of FTO/TiO2 heterojunction photocatalyst was detailed analyzed. In addition, the change of optical band structure and conductivity caused by F doing was correlated with observed carriers transport properties including charge carriers separation, transport and interface transfer in the FTO/TiO2 heterojunction photocatalyst. Finally, the photocatalytic activity, photoelectrocatalytic performance and their photocatalytic mechanism were systematically discussed. The primary results demonstrate that the heterojunction structure in the FTO/TiO2 photocatalyst can effectively separate photogenerated carriers; however, the expense of redox ability is unavoidable. Among these, the FTO(1)/TiO2 sample displays the highest photocatalytic activity, which is attributed to that the benefit of inhibiting recombination has dominant effect on photocatalytic performance.