Sonochemical fabrication, characterization and enhanced photocatalytic performance of Ag₂S/Ag₂WO₄ composite microrods

Ag₂S/Ag₂WO₄ composite microrods, with lengths of 0.2-1 µm and diameters of 20-30 nm, were fabricated by a facile sonochemical route. The as-synthesized products were intensively investigated by a series of physicochemical characterizations, such as N₂ physical adsorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, diffuser reflectance spectroscopy, X-ray photoelectron spectroscopy, photoluminescence spectroscopy and photocurrent response measurements. Ultrasonic irradiation yields an obvious improvement in the photocatalyst texture, for example, an increase in crystallinity and surface area. Moreover, sonochemically fabricated Ag₂S/Ag₂WO₄ microrods display strong visible light absorption and a high transient photocurrent response. The produced intimate Ag₂S/Ag₂WO₄ interface between Ag₂S and Ag₂WO₄ crystal phases largely promotes the separation of photogenerated holes and electrons. High photocatalytic activity and stability were obtained over Ag₂S/Ag₂WO₄ composite microrods. The dye degradation rate constant of Ag₂S/Ag₂WO₄ was 4.7 times and 29.8 times higher than that of bare Ag₂WO₄ and Ag₂S, respectively.