Controllable synthesis of FeWO4/BiOBr in reactive ionic liquid with effective charge separation towards photocatalytic pollutant removal

In the presence of reactive ionic liquid 1-octyl-3-methylimidazolium chloride [Omim]FeCl4, a new ferrous tungstate (FeWO4) was first synthesized by an ethylene glycol-assisted solvothermal process. Subsequently, FeWO4/BiOBr composites were prepared via an ionic liquid N-butyl-N-methylpiperidinium bromide [PP14]Br-assisted solvothermal process in mannitol solution. During the preparation process, [Omim]FeCl4 and [PP14]Br were used as reactants and templates. X-ray diffraction analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry (EDS), transmission electron microscopy, X-ray photoelectron spectroscopy, and other techniques were used to characterize the prepared FeWO4/BiOBr material. Besides, the photocatalytic activity of the FeWO4/BiOBr composites was evaluated by degradation of rhodamineB under visible-light irradiation, revealing that the best ratio of FeWO4 was 3wt%. The photodegradation performance of FeWO4/BiOBr towards tetracycline was better than that of TiO2 (P25). The enhanced photocatalytic activity of the FeWO4/BiOBr composites derived from effective charge separation between FeWO4 and BiOBr. A possible mechanism for the enhanced visible-light photocatalytic performance of FeWO4/BiOBr was proposed.