Controllable topological transformation from BiOCl hierarchical microspheres to Bi 2 WO 6 superstructures in the Bi–W–Cl–O system

Abstract In this work, three-dimensional (3D) Bi2WO6 superstructures assembled by nanosheets were prepared using the topological transformation of BiOCl hierarchical microspheres via a facile one-pot solvothermal method. Interestingly, it was found that the transformation process experienced three stages including BiOCl, BiOCl/Bi2WO6 composites and Bi2WO6 with increasing solvothermal time at 150 °C, which was confirmed by X-Ray Diffraction (XRD), Raman spectrometer and Transmission Electron Microscopy (TEM) results. Importantly, the crystal growth of Bi2WO6 superstructures occurred at the exposed (0 0 1) facets of BiOCl nanosheets with WO66− units replacing the interlaminar Cl atoms. Also, the growth mechanism was revealed and discussed in the thermodynamic and kinetic dynamic aspects. Compared with BiOCl superstructures, the BiOCl/Bi2WO6 composites and Bi2WO6 superstructures showed better photocatalytic activity in the degradation of benzene gases under visible-light irradiation owing to the existence of visible-light-active Bi2WO6. This topological transformation by regulating the solvothermal synthetic conditions may provide a new insight into the controllable synthesis of other 3D compounds.