Design, preparation and enhanced photocatalytic activity of porous BiOCl/BiVO4 microspheres via a coprecipitation-hydrothermal method

Novel three-dimensional BiOCl/BiVO4 hierarchical microspheres featured with p-n heterojunction and a porous structure have been successfully synthesized via a coprecipitation process followed by hydrothermal treatment. Our investigation focuses on the design of a heterojunction structure to overcome limitations of single-component semiconductors, such as poor light response and short carrier lifetime. With elongated heat treatment, the morphology of the BiOCl/BiVO4 composite evolves from porous micro/nanosheets to microspheres with a hierarchical structure, while the monoclinic BiVO4 powders grow in the form of dendritic crystal. Transmission electron microscopy (TEM) analyses demonstrate that the BiOCl and BiVO4 phases distribute uniformly throughout the composite microspheres. Photodegradation rate of rhodamine B (RhB) deposited over the surface of the porous BiOCl/BiVO4 composite is much higher than that of the BiVO4 particles, indicating that hybridization of BiOCl and BiVO4 is an effective way to separate the photogenerated carriers in the composite and the p-n heterojunction improves the photocatalytic activity. [Display omitted] •BiOCl/BiVO4 micro-nanosheets were produced via oriented attachment.•BiOCl/BiVO4 microspheres were obtained by self-assembly of composite sheets.•BiOCl and BiVO4 were distributed uniformly throughout the micro-nanosheet.•The hybridization of BiVO4 with BiOCl could effectively separate the carriers.