Enhanced photocatalytic activity of bismuth oxyiodine (BiOI) porous microspheres synthesized via reactable ionic liquid-assisted solvothermal method

BiOI uniform flower-like porous microspheres have been successfully synthesized through an EG-assisted solvothermal process in the presence of ionic liquid 1-butyl-3-methylimidazolium iodine ([bmim]I) and polyvinyl-pyrrolidone (PVP). The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), nitrogen sorption and diffuse reflectance spectroscopy (DRS). During the reactive process, ionic liquid not only acted as I source but also as template for the fabrication of BiOI porous microspheres. In addition, the photocatalytic activities experiments of BiOI catalyst on the degradation of methyl orange (MO) showed that as-prepared BiOI porous microspheres exhibited higher photocatalytic activity than that of BiOI nanoplates. On the basis of such analysis, it can be assumed that the enhanced photocatalytic activities of BiOI porous microspheres could be ascribed to its energy band structure, high Brunauer–Emmett–Teller (BET) surface area and high surface-to-volume ratios.