Enhanced photoelectrocatalytical activity and stability of Z-scheme heterojunction Black Ti3+ self-doping TNT/Ag/WO3 nanosheet under visible light

Black Ti3+ self-doping TiO2 nanotubes (BTNT) have attracted widespread attention due to their abilities to enhance visible light response and photo-generated electron-hole separation without introducing impurity particles. However, due to the poor stability of Ti3+, the doping of a large amount of Ti3+ is a huge challenge. In this work, we have taken a different approach, and the black Ti3+ self-doping TNT-Ag-WO3 (BAW) photocatalyst was prepared. The BAW Z-scheme photocatalytic (PC) system was successfully constructed. Compared with TNT's PC system (degrade 40.56%), BAW Z-scheme PC system can degrade 97.67% with 20 mg/L MB wastewater after 120 min. By introducing a large number of Ti3+ and O vacancies, the inherent active group is mainly converted from the holes and.OH on the WO3 valence band and.O2− on the TiO2 conduction band, which improved the stability of O vacancies.Before and after the reaction, the reduction of Ti3+ in BTNT is about 30 times that of Ti3+ in BAW. This work provides a reference and basis for constructing Z-scheme heterojunction on BTNT, and also provides new ideas for improving the stability of Ti3+and O vacancies in self-doped TiO2.