Free-standing and Flexible MoS2/rGO Paper Electrode for Amperometric Detection of Folic Acid

The development of flexible electrodes is of considerable current interest because of the increasing demand for modern electronics, portable medical products, and compact devices. We report a new type of flexible electrochemical sensor fabricated by integrating graphene and MoS2 nanosheets. A highly flexible and free-standing conductive MoS2 nanosheets/reduced graphene oxide (MoS2/rGO) paper was prepared by a two-step process: vacuum filtration and chemical reduction treatment. The MoS2/graphene oxide (MoS2/GO) paper obtained by a simple filtration method was transformed into MoS2/rGO paper after a chemical reduction process. The obtained MoS2/rGO paper was characterized by scanning electron microscopy, X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, electrochemical impedance spectroscopy. The electrochemical behavior of folic acid (FA) on MoS2/rGO paper electrode was investigated by cyclic voltammetry and amperometry. Electrochemical experiments indicated that flexible MoS2/rGO composite paper electrode exhibited excellent electrocatalytic activity toward the FA, which can be attributed to excellent electrical conductivity and high specific surface area of the MoS2/rGO paper. The resulting biosensor showed highly sensitive amperometric response to FA with a wide linear range.