Facile synthesis of size-tunable Cu39S28 micro/nanocrystals and small-sized configuration enhanced visible-light photocatalytic activity

A simple strategy to synthesize monodispersed and highly-homogeneous Cu39S28 micro/nano-crystals via a solvothermal method was reported. The structure, morphology and size of the products were characterized by X-ray powder diffraction, X-ray energy dispersive spectroscopy, scanning electron microscopy and transmission electron microscopy. It was found that the size of the products could be tuned by the dosage of PVP, reaction temperature and concentration of reactants. A reasonable nucleation-Ostwald ripening-anisotropy growth mechanism was proposed for the formation of the Cu39S28 hierarchical sphere-like structure based on the time-dependent electron microscopy observations. The visible-light photocatalytic activity of different sizes was evaluated by the degradation of Rhodamine B in the presence of H2O2. For their efficient hydroxyl radicals yielding, the small-sized NCs have a superior photocatalytic activity. Universal visible-light photocatalytic activity of the obtained nanocrystals was also demonstrated. Our results may open up an efficient way for treatment of the dye contaminated waste water using solar radiation.