Effect of hydrothermal temperature on microstructure and optical properties of znin<inf>2</inf>S<inf>4</inf>microspheres and their photocatalytic degradation of methylene blue

Abstract

© 2017, Hanyang University. All rights reserved. ZnIn2S4microspheres were synthesized via a hydrothermal method using zinc chloride (ZnCl2), indium chloride tetrahydrate (InCl3·4H2O) and L-cysteine (C3H7NO2S). The effect of hydrothermal temperatures (160°C, 200°C and 240°C) on the crystallinity, morphology and optical properties of the synthesized powders was investigated. The synthesized products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). The results showed that the synthesized powders were pure ZnIn2S4with a hexagonal structure. The ZnIn2S4powders were microspheres with diameters of 8.3-9.5 µm, constructed from several nanosheets. These nanosheets interconnected with each other, forming a pore structure. With increasing hydrothermal temperature, the nanosheets increased in thickness and the width of the pores between the nanosheets expanded. The ZnIn2S4powder synthesized at 240°C exhibited stronger UV-Vis absorption and photoluminescence (PL) intensities than the other samples. The photocatalytic activity of the ZnIn2S4photocatalyst was investigated by photodegradation of methylene blue under blue light irradiation; 97% of the methylene blue degraded within 210 min. Photostability of the ZnIn2S4photocatalyst was also investigated.