Synergistic effect of oxygen vacancies and doped sulfur over BiOBr for efficient visible photocatalytic removal of dyes

Herein, the BiOBr co-modified with oxygen vacancies (Vo) and doped by sulfur was a promising photocatalyst (Vo-BiOBr-S), which was synthesized by a one-pot solvothermal approach. The TEM showed that Vo-BiOBr-S is a sea urchin-shaped microsphere with a diameter of about 4 μm. The photocatalytic efficiency of Vo-BiOBr-S was studied by removing rhodamine B and methylene blue, which were higher than that of BiOBr, Vo-BiOBr and BiOBr-0.8S, respectively. Additionally, the photocatalyst exhibits high degradation of aqueous solutions containing both rhodamine B and methylene blue. The photocurrent and photoluminescence tests showed that the improved photocatalytic performance of Vo-BiOBr-S was due to the accelerated charge transfer and separation by the internal electric field, which extended the visible light absorption range. Furthermore, experiments free radical trapping revealed that superoxide radicals were the principal active species in this system, contributing to the superior degradation performance of Vo-BiOBr-S. The density of states of the samples was calculated via DFT to analyse the energy band structure. The effectiveness of Vo-BiOBr-S in mineralising RhB under LED light was demonstrated through total organic carbon tests. This study presents a method to design efficient photocatalysts for use in environmental preservation.