Fabrication And Electrochemical Properties Of Molybdenum Disulfide-Graphene Nanosheets Composites

Molybdenum disulfide(MoS2), a 2D layered transition metal dichalcogenides that shows similar structure to graphene, have been recognized as promising candidates for application in electronics and catalysis. The outstanding catalytic activity of MoS2 nanosheet which attributed to the abundant exposed edges makes it shows the superior biosensing performance for the detection of biomolecules, together with its excellent electronic properties. The application of MoS2 as electrode material of electrochemical biosensors has been explored widely. The further application of MoS2 nanoflakes in biosensor is impeded by their inherent limitations of inherently low electronic conductivity. Graphene has attracted enormous research interest owing to its unique properties such as superior electrical conductivity, excellent mechanical flexibility and large specific surface area. Chemical vapor deposition(CVD) is an ideal method to prepare graphene with high quality, few-layer and excellent electrical conductivity that suited for applications within electrochemistry. Hybridization with graphene is one efficient method to improving the electrochemical performance of MoS2. Herein, MoS2-graphene hybrid structures was successful fabricated by mixing the MoS2 nanoflakes which was prepared by liquid-phase exfoliation with the aid of ultrasonication and graphene foam. Specifically, the graphene foam(GF) was prepared by chemical vapor deposition(CVD) with a template of nickel foam.The as-prepared MoS2-graphene composites was characterized by scanning electron microscopy(SEM), X-ray diffraction(XRD) and Raman spectroscopy. SEM images show the MoS2-graphene hybrid possesses sheet-like structure with a smooth surface, and the size of the hybrid ranges from several hundred nanometers to a few micrometers. The hybrid composed of two different sizes of sheets, in which the larger graphene sheets support the smaller MoS2 flakes. The XRD analysis found that the presence of graphene sheets effectively prevent restacking of MoS2 flakes. Raman spectra indicate that the graphene was a few layers with high quality and there have a strong interaction between graphene and MoS2 flakes.The MoS2-graphene composites was transferred onto ITO coated glass via a spray coating method. The MoS2-graphene/ITO acting as an electrode for the determination of Levodopa(L-Dopa) in the presence of uric acid(UA). The electrical performance of MoS2-graphene/ITO electrode were investigated by cyclic voltammetry(CV) and differential pulse voltammetry(DPV). The results show that the sensitivity of the MoS2-graphene/ITO electrode is 0.36 ?A·?M-1 for L-Dopa and is 0.39 ?A·?M-1 for UA. The electrode also shows good selectivity, reproducibility and stability. And it is potential for use in clinical research.