Facile fabrication of TiO2-SiO2-C composite with anatase/rutile heterostructure via sol-gel process and its enhanced photocatalytic activity in the presence of H2O2. Issue 7 (1st April 2022) - Xie, Zhangwen
Abstract: Constructing anatase/rutile heterostructure in TiO2 based materials is a quite powerful approach to enhance their photocatalytic activities. Herein, by simply annealing the sol-gel derived TiO2 -SiO2 composite in N2 atmosphere at 850 °C, TiO2 -SiO2 -C composite (CTS-850) with anatase/rutile heterostructure has been successfully prepared, while the counterpart prepared in air contains only anatase phase. It was proven that the residual organic groups in the sol-gel process were converted into carbon species upon N2 annealing, during which TiO2 in the composite was partially reduced, not only leaving lots of oxygen vacancies on its surface but also promoting the phase transformation. By turning the annealing temperature and atmosphere, a series of control products were further synthesized. Among these samples, the CTS-850 showed the best photocatalytic performance toward Rhodamine B degradation in the presence of H2 O2, which was mainly due to its lowest band gap and the enhanced sensitization of H2 O2 by oxygen vacancies. Moreover, the photocatalytic activity of CTS-850 remained unchanged after five cycles and a proper mechanism was also proposed. Graphical abstract: TiO2 -SiO2 -C composite (CTS-850) with anatase/rutile heterostructure and plenty of oxygen vacancies was prepared by simply annealing the sol-gel derived TiO2 -SiO2 composite in N2 atmosphere at 850 °C, which exhibited unexpected catalytic activity in dye degradation in the presence of H2 O2 . Image 1