Fabrication of Bi2SiO5 hierarchical microspheres with an efficient photocatalytic performance for rhodamine B and phenol removal

Self-assembled three-dimensional (3D) Bi₂SiO₅ microspheres were synthesized via a solvothermal method using glycerol as reaction media and NH₃• H₂O as pH adjustment. The growth of Bi₂SiO₅ crystal was influenced by the solvothermal time. During the preparation process, glycerol acts as a soft template to guide the formation of the hierarchical microspheres. The photocatalytic activities of Bi₂SiO₅ microspheres toward the degradation of Rhodamine B and phenol under light irradiation were evaluated. Bi₂SiO₅ microspheres display much higher photocatalytic activity than the Bi₂SiO₅ nanoplates. The high photocatalytic activity of hierarchical Bi₂SiO₅ microspheres can be ascribed to the enhanced light absorbance, the efficient separation of photo-generated electrons and holes and the large surface area. The main active species during the photocatalytic reaction are • OH and • O₂⁻, proven by terephthalic acid photoluminescence probing technique and nitroblue tetrazolium (NBT) experiments. The Bi₂SiO₅ microspheres are stable during the photocatalytic reaction and can be used repeatedly.