Synthesis of Two-Dimensional Molybdenum Disulfide Nanostructures Using Molybdenum Trioxide Thin Film Via Chemical Vapor Depostion

Two dimensional (2D) materials-based nanostructures have attracted much attention due to their unique properties which exhibit promising prospects for application in catalysis and energy storage devices. Control growth method is important in synthesizing these nanostructures. Chemical vapor deposition (CVD) is a powerful method that provides scalability and controllable way to grow high quality 2D materials-based nanostructures. Here, we report a novel CVD growth method of 2D molybdenum disulfide (MoS2) based different structures in which thin film of molybdenum trioxide (MoO3) was used as the source of molybdenum (Mo), while sulfur (S) powder was used for the chalcogen precursor. Precise control of Mo precursor which is hard to achieve with MoO3 powder promotes high quality growth of MoS2 based nanostructures. In particular, we observed different MoS2-based nanostructures under different growth conditions. The structures were characterized by a variety of techniques to identify their chemical composition and structural nature. Scanning electron microscopy showed the morphology of the vertical plates, nanocrystals, and triangles structures. Raman spectroscopy indicated that the MoS2 based vertical plates are composed of MoO2 and MoS2. Transmission electron microscopy confirmed the multilayer shell of MoS2 with MoO2 core in the nanocrystal structures. We have successfully grown these nanostructures using precise control of the precursor concentration in confined vapor phase. These nanostructures could be relevant in the application of electrocatalytic materials with insufficient long-range conductivity, such as water oxidation catalysts consisting of poorly conducting metal oxides. Confined vapor phase paves the way to control surface structures of MoS2 at the nanoscale to ultimately develop effective catalyst-based materials with high densities of active edge sites at the surface.