Morphology-controllable synthesis and enhanced photocatalytic activity of ZnS nanoparticles

•Morphology-controlled ZnS were achieved by adjusting the Zn/S molar ratios.•Size-related photocatalytic activity of ZnS micro/nanocrystallites was shown.•Different kinds of dyes were used to test the photocatalytic activity of ZnS nanoparticles.•The photocatalysis degradation reaction kinetics of MO was researched.

Well crystallized cubic sphalerite phase ZnS micro/nanocrystallites with controllable morphologies were successfully prepared by a facile and efficient microwave hydrothermal method. The syntheses were carried out by varying the Zn/S molar ratios. The phase compositions, morphologies and optical properties of the as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy and UV–vis diffuse reflectance spectroscopy. Results show that with Zn/S molar ratio ranges from 2:1 to 1:2, the morphology of the prepared ZnS micro/nanocrystallites changed obviously. ZnS nanoparticles with good dispersibility prepared at Zn/S molar ratio of 1:2, which average size is about 20 nm, shows high photocatalytic activity to degrade Methyl orange (MO). The degradation efficiency of ZnS nanoparticles reaches 97.4% under UV irradiation for 20 min. The good ultraviolet absorbing ability and big specific surface area of ZnS nanoparticles are believed to have a positive impact on improving the final degradation rate and degradation efficiency of MO in our research.