Improved photocatalytic activity of RGO/MoS2 nanosheets decorated on TiO2 nanoparticles

Abstract

In this work we have synthesized a heterogeneous hybrid junction of reduced graphene oxide (RGO)/MoS₂ and hybrid composites of TiO₂–RGO/MoS₂ using a hydrothermal method. The hybrid composites were characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and electron paramagnetic resonance spectroscopy (EPR). Raman spectroscopy displays that the hybrid junction was formed between two dimensional RGO and few layer MoS₂ nanosheets. In the TiO₂–RGO/MoS₂ hybrid composite, EPR studies show that the lattice Ti³⁺ signal was decreased and at the same time equivalent amounts of the O˙⁻ signal increased under UV light irradiation. These results suggested that the interfacial charge transferred from the TiO₂ surface to the MoS₂ surface active sites directly or through the RGO nanosheets toward suppressing the recombination rate of the electron–hole pairs for an enhanced methylene blue degradation. RGO behaves like a conductor, it accepted only electrons and transported to the active sites through separating the potential level distance between the two semiconductors.