Stoichiometry-Controlled Fabrication of CuxS Hollow Structures With Cu2O as Sacrificial Templates

In this work, we report the successful composition-controlled synthesis of copper sulfides hollow structures using Cu 2 O nanocrystals as sacrificial templates via a Kirkendall-based process. The direct introduction of S 2– glycol solution into the Cu 2 O-containing mother solution produced Cu 7 S 4 nanocrystals, while CuS formed with Cu 2 O experienced a separation and drying process as sacrificial templates. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) data reveal that a layer of CuO existed on the surface of the dried Cu 2 O. We believe the surface states of Cu 2 O templates played key roles in the stoichiometry control. The presence of CuO catalyzed the oxidation from Cu + to Cu 2+ . The type of sulfur source is importance for the formation of hollow structures. The UV–vis–NIR absorption investigation demonstrates a significant quantum confinement effect and stoichiometry-dependent features. It may provide a new approach for the stoichiometry-controlled synthesis of chalcogenides and would aid a better understanding of the optical behaviors of copper sulfides.