Photocatalytic performance of oxygen vacancy rich-TiO2 combined with Bi4O5Br2 nanoparticles on degradation of several water pollutants

Despite significant advancements in the improvement of heterogeneous photocatalysis towards water treatment, these processes still have some bottlenecks. In this research paper, oxygen vacancy rich-TiO₂ was combined with Bi₄O₅Br₂ nanoparticles (denoted as TiO₂-OVs/Bi₄O₅Br₂) by eco-friendly hydrothermal approach. The outcomes demonstrated that the photoactivity strongly depends on plenteous active sites, reinforced charge segregation, as well as striking visible-light absorption ability in TiO₂-OVs/Bi₄O₅Br₂ nanocomposite with n-n heterojunction. The photoactivity was found to follow the trend: TiO₂-OVs/Bi₄O₅Br₂ (30%) > TiO₂-OVs > TiO₂. Briefly, the removal efficiencies of RhB, MB, and fuchsine were 100%, 96.2%, and 84.7% using TiO₂-OVs/Bi₄O₅Br₂ (30%) in 120 min, while they were 25.1%, 20.0%, and 15.3% over the TiO₂, respectively. Further, the boosted rate constant was observed for the photoreduction of Cr (VI) on the TiO₂-OVs/Bi₄O₅Br₂ (30%) nanocomposite, which was 19.4 and 7.8-folds more than the TiO₂ and TiO₂-OVs photocatalysts, respectively. The radical scavenging tests with different quenchers demonstrated that holes and superoxide anion radicals take part in the degradation reaction. Finally, by investigating the electrochemical properties, a mechanism was offered to describe the improved e^–/h⁺ pairs separation and migration. This research displayed that the design of n-n heterojunction using TiO₂-OVs could be suitable for severely improving photocatalytic performance of TiO₂ under visible light.