Construction of BiOF/BiOI nanocomposites with tunable band gaps as efficient visible-light photocatalysts

[Display omitted] •Mesoporous BiOF, BiOI and BiOF/BiOI photocatalysts have been prepared using simple coprecipitation method.•Photocatalysts characterized using: DRS, PXRD, SEM, EDX, BET and PL.•The observed red shifts of emission wavelength agree with the trend in the measured energy gaps for the selected composites.•The rate of the photocatalytic reactions depends on the percent doping of BiOI added.•Highest activity achieved for composite where BiOI percent is 60%. A series of BiOF/BiOI heterojunction composites photocatalysts has been prepared via a simple coprecipitation method and characterized by using UV–vis (UV–vis) diffuse reflectance spectroscopy (DRS), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller for determination of the specific surface area and porosity (BET), high resolution transmission electron microscopy (HRTEM) and photoluminescence (PL). The enhanced photocatalytic activity for removal of the pharmaceutical compound Diclofenac Potassium commercially available as Voltfast sachets under visible light irradiation was demonstrated by comparing heterojunction prepared composites photocatalysts with that of pure BiOF and BiOI photocatalysts prepared under the same conditions. Based on the experimental conditions, the highest activity was achieved for the composite contains 40% BiOF and 60% BiOI showing comparable activities to that of pure BiOI. To the best of our knowledge, this study is the first to report the preparation of BiOF/BiOI composites photocatalysts and their use in the photocatalytic removal of Diclofenac Potassium from aqueous solution.