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

Abstract

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 @ Ti[Formula: see text] self-doped TiO2 nanosheet heterostructure with tunable Ti[Formula: see text] 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 Ti[Formula: see text] doping. Due to the synergistic effect of Ti[Formula: see text] 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 Ti[Formula: see text] doping and associated oxygen vacancies, extended the optical absorption of TiO2 into visible region and enhanced the separation efficiency of photogenerated electron-hole pairs, which finally resulted in improved photocatalytic performance of the Si@Ti[Formula: see text] 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.