Microwave-assisted synthesis of oxygen vacancy associated Bi–TiO2 nanocomposite for degradation of rhodamine B under visible light irradiation

Abstract

Generally, a Bi-doped TiO₂ nanocomposite was synthesized by a microwave-assisted hydrothermal method to introduce Bi₄Ti₃O₁₂ and an oxygen vacancy onto the pristine TiO₂. The optimized composite 6Bi–TiO₂ exhibits a good photocatalytic ability for degradation of rhodamine B (RhB), and the calculated reaction rate constant is about 13.7 times higher than that of pristine TiO₂. After 60 minutes of light irradiation, the 6Bi–TiO₂ sample achieved a degradation rate of 95% and that of the pristine TiO₂ was 21%. Furthermore, the catalyst retains a good photocatalytic ability after recycling five times. The enhanced photocatalytic ability can be credited to the improved charge separation efficiency, caused by the altered band structure after the anchoring of Bi₄Ti₃O₁₂, and the oxygen vacancy also plays a crucial role in the degradation process. This study offers insights into the application of a microwave-assisted hydrothermal method in the effective synthesis of Bi₄Ti₃O₁₂ on TiO₂ by a Bi-doping strategy.