Controllable synthesis and enhanced photocatalytic properties of Cu2O/Cu31S16 composites

Highlights: ► Facile sonochemical route. ► The content of Cu31S16 in the Cu2O/Cu31S16 can be easily controlled. ► Structure and optical properties of Cu2O/Cu31S16 were discussed. ► Enhanced photocatalytic property of Cu2O/Cu31S16. ► Cu2O/Cu31S16 core/shell structures were more stable than single Cu2O particles. -- Abstract: The controlled synthesis of Cu2O/Cu31S16 microcomposites with hierarchical structures had been prepared via a convenient sonochemical route. Ultrasonic irradiation of a mixture of Cu2O and (NH2)2CS in an aqueous medium yielded Cu2O/Cu31S16 composites. The content of Cu31S16 in the Cu2O/Cu31S16 can be easily controlled by adjusting the synthesis time. The Cu31S16 layer not only protected and stabilized Cu2O particles, but also prohibited the recombination of photogenerated electrons–holes pair between Cu31S16 and Cu2O. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) spectra, ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence (PL) spectroscopy were used to characterize the products. Photocatalytic performance of the Cu2O/Cu31S16 hierarchical structures was evaluated by measuring the decomposition rate of methyl orange solution under natural light. To the best of our knowledge, this is the first report on the preparation and photocatalytic activity of Cu2O/Cu31S16 microcomposite. Additionally, the Cu2O/Cu31S16 core/shell structures were more stable than single Cu2O particles during photocatalytic process since the photocatalytic activity of the second reused architecture sample was much higher than that of pure Cu2O. The Cu2O/Cu31S16 microcomposites may be a good promising candidate for wastewater treatment.