Hydrothermal Synthesis of Graphene/Bi2WO6 Composite with High Adsorptivity and Photoactivity for Azo Dyes

Graphene/ Bi 2 WO 6 composites have been synthesized by hydrothermal reduction at 160°C for 24 h using ethanol as the reducing agent. All as‐prepared composites were characterized using X‐ray diffraction ( XRD ), UV –vis diffuse reflectance spectroscopy, FT ‐ IR spectroscopy, Raman spectroscopy, scanning electron microscopy, high‐resolution transmission electron microscopy, N 2 adsorption, and photocatalytic activity evaluation. The effective charge separation of graphene/ Bi 2 WO 6 composites was caused by the electrical conduction of graphene which is the most important factor. The results have proved the formation of interfacial contact between graphene nanosheets and Bi 2 WO 6 nanoplates. The adsorptivity for azo dyes was enhanced greatly with the introduction of graphene. The oxy‐functional groups located at the edges of graphene were responsible for the enhanced adsorptivity. As‐prepared graphene/ Bi 2 WO 6 composites exhibited enhanced light absorption from UV to visible‐light region. In addition, the introduction of graphene would also result in smaller crystalline size and lower crystallinity of Bi 2 WO 6 . Graphene/ Bi 2 WO 6 composites containing an appropriate amount of graphene were proved to exhibit higher adsorptivities and photocatalytic activities for azo dyes. High photocatalytic activities of graphene/ Bi 2 WO 6 composites were considered to be the synergetic effects of high adsorption, high light absorption, and high electrical conduction induced by the introduction of graphene.