Enhanced photocatalytic performance of Au nanoparticles-modified rose flower-like Bi2WO6 hierarchical architectures

摘要

Rose flower-like Bi₂WO₆ hierarchical architectures with average diameter of 7 μm were synthesized via a hydrothermal route. The as-synthesized Bi₂WO₆ hierarchical architectures were decorated with Au nanoparticles (20–110 nm in size) by a photocatalytic reduction method. The prepared samples were systematically investigated by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, electrochemical impedance spectroscopy and photocurrent response. The photocatalytic performance of the samples was evaluated by the degradation of RhB in aqueous solution under simulated sunlight irradiation. It is observed that Au–Bi₂WO₆ composite exhibits a photocatalytic activity much higher (about 2.7 times higher) than that of bare Bi₂WO₆. The enhanced photocatalytic activity of Au–Bi₂WO₆ can be attributed to the enhanced separation of photogenerated electron–hole pairs due to the electron migration from Bi₂WO₆ hierarchical architectures to Au nanoparticles. As a result, more electrons and holes are able to participate in the photocatalytic reactions. The underlying photocatalytic mechanism was discussed.