Two-Step Facile Preparation of MoS2·ZnO Nanocomposite as Efficient Photocatalyst for Methylene Blue (Dye) Degradation

Abstract

In this work, we report the synthesis of binary semiconductor nanocomposite (NC) comprising spherical ZnO nanoparticles stacked with two-dimensional MoS2 nanosheets, utilizing a facile microwave assisted synthesis technique. The fabricated product was characterized by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy instrument, scanning electron microscopy, Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDAX), inductively coupled plasma analysis and Fourier transform infrared spectroscopy to distinguish the structure and morphology of arranged NC. Ultraviolet–visible spectroscopy was used to understand the optical properties of MoS2·ZnO NC. Optical transmission spectra gave a distinct red shift in the band gap of ZnO after making composition with MoS2 nanosheets which eventually shows higher retention of visible light. This occurs due to effective separation of photogenerated charge carriers and rapid charge transfer to reactions sites of conduction band potentials of both ZnO and MoS2 both. We plot that MoS2·ZnO NC has a band gap of 2.73 eV which is fundamentally a long way from the band gap of ZnO (~ 3.3 eV). The outcomes recommended the effective fading out of methylene blue (more than 95%) in 1 h on the illumination of visible light. Besides, the association of MoS2 prevents photo-corrosion of the ZnO bringing about upgraded photostability of the catalyst during the reaction. Moreover, we presented a recyclability test of the photocatalyst for five subsequent times to get the efficient dye degradation.