Synthesis and electrochemical performances of layered tungsten sulfide-graphene nanocomposite as a sensing platform for catechol, resorcinol and hydroquinone

The Layered tungsten sulfide (WS2)-graphene (Gr) composites were prepared by a facile l-cysteine-assisted solution-phase method. Field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations showed that layered WS2 nanosheets were highly wrapped in the creasy Gr. The electrochemical properties of the nanocomposite film were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The as-prepared WS2-Gr composite showed excellent electrochemical catalytic activities toward the oxidation of catechol (CT), resorcinol (RS) and hydroquinone (HQ). The superior electrochemical performances of the composites could be attributed to the robust composite structure and superior conductivity, large surface area and good flexibility of WS2-Gr composites. Some kinetic parameters, such as the electron transfer number (n), charge transfer coefficient (α) and the apparent heterogeneous electron transfer rate constant (ks), were calculated. Differential pulse voltammetry was used for the simultaneous determination of CT, RS and HQ in their ternary mixture. The calibration curves for CT, RS and HQ were obtained in the range of 1 × 10−6 to 1 × 10−4. The detection limits were 1 × 10−7 mol L−1 for RS and HQ, and 2 × 10−7 mol L−1 for CT (S/N = 3). The developed sensor was used to detect CT, RS and HQ in environmental water samples with recoveries of 93.6-104.8%