Ionic liquid assisted in-situ construction of S-scheme BiOI/Bi2WO6 heterojunctions with improved sunlight-driven photocatalytic performance

In this study, BiOI/Bi2WO6 heterojunctions were in-situ prepared by a hydrothermal routine with the aid of ionic liquid N-butyl pyridine iodized salt ([Epy]I). The BiOI/Bi2WO6 composites were studied by a series of characterization methods. The results manifest that BiOI/Bi2WO6 heterojunctions were in-situ constructed, proven by high-resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) characterization. Construction of BiOI/Bi2WO6 heterojunctions dramatically facilitates the separation of photoexcited carriers due to the interfacial electric field between BiOI and Bi2WO6. All the composites display higher sunlight-driven photocatalytic activity than the bare Bi2WO6 benefited from promoted separation of photoinduced carriers. The BiOI/Bi2WO6 heterojunctions hold excellent stability. An S-scheme was discussed to elaborate the separation and transfer of photogenerated carriers of BiOI/Bi2WO6 heterojunctions.