One-pot synthesis of BiOCl half-shells using microemulsion droplets as templates with highly photocatalytic performance for the degradation of ciprofloxacin

Ultrathin BiOCl half-shells have been synthesized via an ionic liquid-in-water (IL/W) microemulsion, applying the liquid–liquid boundary of the emulsion system as a template. Surfactant TX-100 acted as the stabilizer of the IL-microemulsion, which is of critical importance for the formation of BiOCl half-shells. The hollow structures were characterized using X-ray diffraction, scanning and transmission electron microscopy, diffuse reflectance spectroscopy and specific surface area, respectively. Possible formation mechanisms for the BiOCl half-shells were discussed. Moreover, the ultrathin BiOCl half-shells exhibited distinctly enhanced photocatalytic efficiency toward the degradation of colourless ciprofloxacin (CIP, a representative broad-spectrum antibiotic agent) under solar light irradiation as compared to BiOCl nanosheets. The photogenerated reactive species are verified by scavenger experiments, which reveals that O2−and h+ were the two major photoactive species toward the photodegradation of CIP over ultrathin BiOCl half-shells under solar-light. The enhanced activities of ultrathin BiOCl half-shells were mainly ascribed to the synergistic effect of the increased light-harvesting, larger BET surface area, faster separation and transfer of electron-hole pairs. It is hoped that the ionic liquid microemulsion-mediated route can be extended to the purposive design and fabrication of other halogen-containing inorganic hollow materials.