2D/2D Biochar/Bi₂WO₆ Hybrid Nanosheets with Enhanced Visible-Light-Driven Photocatalytic Activities for Organic Pollutants Degradation

In this work, a novel two-dimensional/two-dimensional(2D/2D) hybridphotocatalyst consisting of Bi2WO6 (BWO) nanosheetsand cotton fibers biochar (CFB) nanosheets was successfully preparedvia a facile hydrothermal process. The as-prepared photocatalystswere characterized by a variety of techniques, including X-ray diffraction,scanning electron microscopy, transmission electron microscopy, X-rayphotoelectron spectroscopy, and UV-vis diffuse reflectancespectroscopy. It was revealed that amorphous CFB nanosheets were uniformlyimmobilized on the surface of crystalline BWO nanosheets, and an intimatecontact between CFB and BWO was constructed. The photocatalytic activitiesof the prepared BWO and CFB-BWO photocatalysts were evaluatedby photocatalytic degradation of rhodamine B (RhB) and tetracyclinehydrochloride (TC-HCl) in aqueous solutions under visible-light irradiation.Compared to the pristine BWO, the CFB-BWO composite photocatalystsexhibited significant enhancement in photocatalytic activities. Amongall CFB-BWO samples, the 9CFB-BWO sample with the CFBmass ratio of 9% exhibited optimal photocatalytic activities for RhBor TC-HCl degradation, which was ca. 1.8 times or 2.4 times that ofthe pristine BWO, respectively. The improvement in photocatalyticactivities of the CFB-BWO photocatalysts could be ascribedto the enhanced migration and separation of photogenerated chargecarriers due to the formation of a 2D/2D interfacial heterostructurebetween CFB and BWO. Meanwhile, the possible mechanism of CFB-BWOfor enhanced photocatalytic performance was also discussed. This workmay provide a new approach to designing and developing novel BWO-basedphotocatalysts for the highly efficient removal of organic pollutants.