Microwave-assisted hydrothermal synthesis of marigold-like ZnIn2S4 microspheres and their visible light photocatalytic activity

Marigold-like ZnIn2S4 microspheres were synthesized by a microwave-assisted hydrothermal method with the temperature ranging from 80 to 195 °C. X-ray diffraction, X-ray photoelectron spectroscopy, nitrogen sorption analysis, UV–visible spectroscopy, scanning electron microscopy and transmission electron microscopy were used to characterize the products. It was found that the crystallographic structure and optical property of the products synthesized at different temperatures were almost the same. The degradation of methyl orange (MO) under the visible light irradiation has been used as a probe reaction to investigate the photocatalytic activity of as-prepared ZnIn2S4, which shows that the ZnIn2S4 sample synthesized at 195 °C shows the best photocatalytic activity for MO degradation. In addition, the photocatalytic activities of all the samples prepared by the microwave-assisted hydrothermal method are better than those prepared by a normal hydrothermal method, which could be attributed to the formation of more defect sites during the microwave-assisted hydrothermal treatment.