Pivotal Role of Fluorine in Tuning Band Structure and Visible-Light Photocatalytic Activity of Nitrogen-Doped TiO2

A study was conducted to demonstrate the role of fluorine in tuning band structure and visible-light photocatalytic activity of nitrogen-doped TiO 2. It was observed that incorporating F into N-doped TiO2 enhanced the oxidative power of the hole in the valence band (hVB), but decreased the reduction ability of electrons in conduction band (eCB). The enhancement in the oxidation power of the hVB accelerated the oxidation of water and caused the reduction reaction to occur in the absence of any reductive sacrificial reagents. Theoretical and experimental studies revealed that co-doping of F can be used to tune the band structure of the VB and the CB of N-doped TiO2 owing to synergistic interactions between N and F. The study provided significant information for designing new photocatalysts and to control the photocatalytic reactions.