A one-step ionic liquid-assisted ultrasonic method for the preparation of BiOCl/m-BiVO4 heterojunctions with enhanced visible light photocatalytic activity

By combining the advantages of both ionic liquids and ultrasound, a novel method, namely the ionic liquid-assisted ultrasonic method, was developed to prepare BiOCl/m-BiVO4 heterojunctions in several hours at room temperature. Through this method, BiOCl/BiVO4 heterojunctions with different BiOCl contents can be conveniently synthesized via simply changing the amount of 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) used during the preparation process. X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy were used to examine the structures of the as-prepared BiOCl/m-BiVO4 heterojunctions. The morphologies were characterized via scanning electron microscopy and transmission electron microscopy. The results suggest that the as-prepared BiOCl/m-BiVO4 heterojunctions have high photocatalytic activity and stability for the degradation of Rhodamine B under both visible light and sunlight irradiation at room temperature. Moreover, a possible mechanism was proposed.