Enhanced visible-light photocatalytic activity of plasmonic Ag and graphene co-modified Bi2WO6 nanosheets

Photocatalytic degradation of pollutants in water has received much attention due to increasing environmental problems. In this study, a visible-light-driven plasmonic silver–graphene–bismuth tungsten (Ag–G–Bi2WO6) composite photocatalyst was prepared. Firstly, the graphite oxide (GO)–Bi2WO6 composite was prepared using a hydrothermal process, followed by a chemical reduction process using ethyl glycol (EG) as the reducing agent to form the G–Bi2WO6 composite. Then, Ag nanoparticles (NPs) were loaded onto the G–Bi2WO6 composite using a simple photochemical reduction process under xenon lamp irradiation to form the Ag–G–Bi2WO6 composite. The prepared samples were characterized using X-ray diffraction, transmission electron microscopy, nitrogen adsorption–desorption isotherm, UV-visible diffuse reflectance spectroscopy and electrochemical impedance spectroscopy. The photocatalytic activities of the prepared samples were evaluated by the photocatalytic degradation of rhodamine B (RhB) aqueous solution at ambient temperature under visible-light irradiation. The results showed that the photocatalytic activity of Bi2WO6 was significantly enhanced by the loading of Ag and graphene. The high photocatalytic activity is attributed predominantly to the hybridization of the surface plasmonic resonance (SPR) effect of Ag NPs and the specific electronics effect of graphene on the Bi2WO6 surface, thus enhancing the generation and separation of photogenerated charge carriers of Bi2WO6. Meanwhile, the excellent adsorption capacity of graphene also contributes to the enhancement of photocatalytic activity. This work highlights the design and preparation of new photocatalysts using plasmonic Ag and graphene as cocatalyst.