Investigations of an electrochemical platform based on the layered MoS2-graphene and horseradish peroxidase nanocomposite for direct electrochemistry and electrocatalysis.

The self-assembly of layered molybdenum disulfide-graphene (MoS2-Gr) and horseradish peroxidase (HRP) by electrostatic attraction into a novel hybrid nanomaterial (HRP-MoS2-Gr) is reported. The properties of the MoS2-Gr were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). UV-vis and Fourier transform infrared spectroscopy (FT-IR) indicate that the native structure of the HRP is maintained after the assembly, implying good biocompatibility of MoS2-Gr nanocomposite. Furthermore, the HRP-MoS2-Gr composite is utilized as a biosensor, which displays electrocatalytic activity to hydrogen peroxide (H2O2) with high sensitivity (679.7 μA mM(-1)cm(-2)), wide linear range (0.2 μM-1.103 mM), low detection limit (0.049 μM), and fast amperometric response. In addition, the biosensor also exhibits strong anti-interference ability, satisfactory stability and reproducibility. These desirable electrochemical properties are attributed to the good biocompatibility and electron transport efficiency of the MoS2-Gr composite, as well as the high loading of HRP. Therefore, this biosensor is potentially suitable for H2O2 analysis in environmental, pharmaceutical, food or industrial applications.