Abstract
An efficient visible-light-driven Ag/AgCl/ZnWO4 photocatalyst was synthesized by a facile ultrasonic-assisted precipitation-photoreduction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and UV-vis diffuse reflectance spectroscopy (DRS) were employed to characterize the composition, morphology, structure, and optical property of the obtained catalysts. The results indicated that the as-prepared photocatalyst, formed by Ag/AgCl nanoparticles dispersed on the surface of ZnWO4 nanorods, demonstrated remarkable absorbance in the visible light region. The Ag/AgCl/ZnWO4 composite displays much superior visible light photocatalytic activity for methyl orange (MO) and methylene blue (MB) degradation compared with pure ZnWO4 and Ag/AgCl nanocrystals, as well as the conventional visible-light photocatalyst N-doped TiO2. On the basis of the active species trapping experimental results and band structure analysis, a photocatalytic mechanism is proposed. The predominantly enhanced performance can be ascribed to the surface plasmon resonance of Ag nanoparticles and the high separation efficiency of photogenerated electron-hole pairs. In addition, the sample of Ag/AgCl/ZnWO4 also exhibits good stability and durability due to it depicts high photocatalytic activity even after five cycles. (C) 2014 Elsevier B.V. All rights reserved.