The synthesis of hierarchical nanostructured MoS ₂ /Graphene composites with enhanced visible-light photo-degradation property

Novel two-dimensional materials with a layered structure are of special interest for a variety of promising applications. Herein, MoS ₂ and MoS ₂ /Graphene nanocomposite with hierarchical nanostructure were successfully synthesized employing a one-step hydrothermal method. Photo-degradation of methylene blue (MB) and rhodamine (RHB) were adopted to assess the photo-degradation ability of the products. Comparing with bare MoS ₂ , the hierarchical MoS ₂ /Graphene nanocomposite achieved relatively higher degradation rate of 99% in 28 min for MB as well in 50 min for RHB. These results verified that this proposed hierarchical nanocomposite is a good photo-degradation semiconductor. The excellent performance was mainly ascribed to the synergistic effect of MoS ₂ and graphene layers. The MoS ₂ possessing a band gap of 1.9 eV would provide abundant electron-hole pairs. The graphene layers with excellent electro-conductivity could realize the quick transport of electrons via its extended π-conjugation structure, consequently benefiting the separation of photo-generated carriers. These findings indicate that the graphene layer is a promising candidate as a co-catalyst for MoS ₂ photo-catalyst, and also provide useful information for understanding the observed enhanced photocatalytic mechanism in experiments.