CoS2-decorated ionic liquid-functionalized graphene as a novel hydrazine electrochemical sensor.

Cobalt disulfide-decorated ionic liquid-functionalized graphene nanocomposites were prepared herein and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The as-prepared nanocomposites were subsequently used to build a modified glassy carbon electrode serving as a hydrazine (N2H4) electrochemical sensor. The electrocatalytic performance of the prepared sensor towards the N2H4 oxidation reaction was evaluated by cyclic voltammetry (CV) and amperometric methods. A linear dependence was found between the oxidation peak current and the concentration of N2H4. Thus, linear calibration plots were obtained over wide linear ranges of 5-100 μM (R2 = 0.9898) and 100-400 μM (R2 = 0.9852), with a relatively low detection limit of 0.39 μM (S/N = 3). The prepared sensor exhibited good electrocatalytic performance (i.e., sensitivity, reproducibility, and selectivity) towards the detection of N2H4. The sensor was successfully used for the practical determination of N2H4 in lake water samples with satisfactory recoveries.