Template-Free Solvothermal Synthesis of Flower-Like BiOBr Microspheres in Ethanol Medium for Photocatalytic Applications

Abstract

Three-dimensionally (3D) BiOBr microflowers were prepared by a simple solvothermal method, employing Bi(NO₃)₃ · 5H₂O and NaBr as starting reagents in ethanol. The structural, light absorption and morphological properties of as-prepared BiOBr microspheres were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis diffuse reflectance spectroscopy (DRS), etc. The results showed that ethanol acted not only as a solvent but also as a template in 3D BiOBr preparation. The BiOBr microspheres exhibited superior photocatalytic activity compared with 2D BiOBr nanosheets, far exceeding that of TiO₂ (Degussa, P25). It was found that both superoxide radical (O₂^•-) and holes (h⁺) played a key role in the degradation of RhB by BiOBr microflowers.