Amperometric sensing of hydroquinone using a glassy carbon electrode modified with a composite consisting of graphene and molybdenum disulfide

Well-dispersed composites of graphene and molybdenum disulfide were synthesized without using a mediator. The composites were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The electrochemical properties of a glassy carbon electrode (GCE) modified with the graphene/MoS2 composite were investigated by electrochemical impedance spectroscopy and cyclic voltammetry. Hydroquinone was selected as a model target to show the sensing capability of the modified GCE. The GCE, best operated at a working voltage of 0.10 V (vs. Ag/AgCl), exhibits excellent catalytic activity towards hydroquinone, with a linear response in the 0.5 to 300 mu M concentration range and a 37 nM detection limit (at an S/N ratio of 3). The superior performance of the GCE is attributed to the synergistic effects of graphene and MoS2.