Ag/Bi2WO6 plasmonic composites with enhanced visible photocatalytic activity

Three-dimensional flower-like Bi2WO6 microspheres with the diameter of about 4 μm were prepared by a facile hydrothermal method using bismuth nitrate pentahydrate and sodium tungstate dihydrate as raw materials. A novel Ag-modified Bi2WO6 was synthesized through a simple and practical photoreduction process. The UV–vis diffuse reflectance spectra indicate that the Ag/Bi2WO6 samples have a significantly enhanced optical absorption in the visible light region than that of pure Bi2WO6 microspheres due to the surface plasmon resonance (SPR) of Ag nanoparticles on the surface of pure Bi2WO6. The photocatalytic activities of the as-prepared samples were evaluated by the decolorization of rhodamine B under simulated sun-light irradiation. The results reveal that the photocatalytic activities of the Ag/Bi2WO6 samples increase first and then decrease with increasing amount of loading Ag and the 1.0 wt% Ag-loaded Bi2WO6 sample exhibits the best photocatalytic activity compared with the other samples. The enhanced photocatalytic activity could be attributed to the synergistic effect of the strong SPR and the effective separation of photogenerated electrons and holes caused by Ag nanoparticles.