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

Abstract

Graphene/Bi2WO6 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, N2 adsorption, and photocatalytic activity evaluation. The effective charge separation of graphene/Bi2WO6 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 Bi2WO6 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/Bi2WO6 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 Bi2WO6. Graphene/Bi2WO6 composites containing an appropriate amount of graphene were proved to exhibit higher adsorptivities and photocatalytic activities for azo dyes. High photocatalytic activities of graphene/Bi2WO6 composites were considered to be the synergetic effects of high adsorption, high light absorption, and high electrical conduction induced by the introduction of graphene.

Nanostructured Graphene-Titanium Dioxide Composites Synthesized by a Single-Step Aerosol Process for Photoreduction of Carbon Dioxide

“…The D/G band ratios of the two samples increased to 1.163 and 1.083, respectively. This is possibly due to the presence of dangling bonds of the sp 2 carbon or soft defects created due to photoreduction (Zhang et al, 2013), as more surface functional groups were presented in the lower temperature samples. Both D and G peaks become more defined than those in the 800°C sample, suggesting that the GO has been photocatalytically reduced to rGO and possibly possesses better electronic properties.…”

Fabrication of novel heterostructured few layered WS2-Bi2WO6/Bi3.84W0.16O6.24 composites with enhanced photocatalytic performance

“…5b. The Raman peaks of BWO mainly appear in the range of 100-300 cm −1 and are assigned to the vibrational mode of Bi-O and WO 4 , and 600-900 cm −1 assigned to the antisymmetric bridging mode (719 cm −1 ), antisymmetric/symmetric A g modes of the terminal O-W-O (796 and 825 cm −1 , respectively) [55][56][57]. By comparison, the Raman spectra of WS 2 -BWO present the characteristic peaks of WS 2 and BWO but show a slight difference from those of pure WS 2 and BWO, which reveals the formation of a heterostructure between WS 2 and BWO in the WS 2 -BWO composite.…”

Highly active magnetic bismuth tungstate/magnetite composite under visible light irradiation in the presence of hydrogen peroxide

“…This could be due to the dark red color of the composites after doping with Fe 3 O 4 [25]. [34]. In addition, the RhB molecules display strong light absorption in the visible light region.…”