One-Step Synthesis of Si@Ti3+ Self-Doped TiO2 Heterostructure with Enhanced Photocatalytic Performance

Heterostructure construction and doping provide two powerful routes for manipulating charge carrier separation, electrical transport, optical response, and interface kinetics for photocatalysis. However, the literature reported synthetic methods until now were very time-consuming. In this work, a facile one-pot hydrothermal reaction route was designed to synthesize Si nanospheres @ Ti3+ self-doped TiO2 nanosheet heterostructure with tunable Ti3+ doping levels at different hydrothermal temperatures. It was found that the precursor Si nanospheres not only serve as supporter of TiO2 nanosheets, but also are the inducement of Ti3+ doping. Due to the synergistic effect of Ti3+ doping and Si/TiO2 heterojunctions, the optimal sample exhibited 6.74-fold enhancement for rhodamine B (RhB) photodegradation under Xe lamp irradiation compared with the pristine TiO2. The construction of Si/TiO2 heterojunction, as well as the introduced Ti3+ doping and associated oxygen vacancies, extended the optical absorption of TiO(2 )into visible region and enhanced the separation efficiency of photogenerated electron-hole pairs, which finally resulted in improved photocatalytic performance of the Si@Ti3+ self-doped TiO2 core-shell nanospheres. The designed hydrothermal route opens up an opportunity to the synthesis of doped hetero-photocatalysts in an efficient way.