Tailoring bismuth oxybromide microsphere properties with different additives for applications in visible-light driven wastewater treatment

Abstract

The increasing complexity of water pollution presents a serious threat to public health, spurring a growing demand for advanced materials capable of efficiently removing multiple pollutants in wastewater treatment. Photocatalysts, particularly those with tunable structural and surface characteristics, have gained recognition as potential solutions for this purpose. In this study, bismuth oxybromide (BiOBr) photocatalysts were prepared through the solvothermal approach using different shape-controlling agents to investigate their impact on crystal properties, Brunauer-Emmett-Teller (BET) surface area (S_BET), morphology and photocatalytic performance. Through comprehensive characterization using XRD, FESEM-EDX, HRTEM-SAED, and BET analyses, it was found that the choice of shape-controlling agent significantly affected the crystallite size, the (110)/(012) crystallographic plane ratio, hierachical particle morphology, size distribution and S_BET of the synthesized BiOBr. Among the samples, BiOBr synthesized with polyvinylpyrrolidone (PVP) exhibited the smallest crystallite size, narrow particle size distribution, and the highest S_BET, along with a 3D hierarchical porous flower-like microsphere morphology. These features led to the highest photodegradation activity for Rhodamine B (RhB) dye when irradiated with visible light. Additionally, the BiOBr synthesized with PVP exhibited effective antibacterial activity against Escherichia coli, further underscoring its potential for disinfection in wastewater treatment. The results highlight the potential of BiOBr, particularly the PVP-mediated synthesis, as an effective photocatalyst for wastewater remediation application.