Controllable synthesis of hierarchical CuS/ZnS hetero-nanowires as high-performance visible-light photocatalysts

Abstract

Novel hierarchical CuS/ZnS hetero-nanowires were designed and successfully synthesized through a template-free and surfactant-free chemical solution method with a mixed solvent of dimethyl sulfoxide and ethylene glycol. The precursors of CuS and the molar ratio of Cu : Zn, play a crucial role in controlling the morphology of the CuS/ZnS heterostructure. The precursors of CuS serve both as a source material for chemical transformation to CuS and as sacrificial templates for the growth of ZnS nanosheets by adding zinc(II) ions, finally forming a ZnS/CuS hierarchical nanomaterial with p–n heterojunctions. The as-prepared samples were examined by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy and Brunauer–Emmett–Teller measurements. Photocatalytic activities for methylene blue and rhodamine B were investigated under visible-light irradiation, and appreciably increased photocatalytic activity compared to individual counterparts is achieved by the hierarchical CuS/ZnS hetero-nanowires. The p–n heterojunction, one-dimensional nanostructures and large specific surface area are responsible for the improved photocatalytic activities.