Electrocatalytic oxidation of hydrazine and hydroxylamine at gold nanoparticle—polypyrrole nanowire modified glassy carbon electrode

A novel electrochemical sensor was fabricated by electrodeposition of gold nanoparticle on pre-synthesized polypyrrole (PPy) nanowire, forming an Au/PPy composite matrix on glassy carbon electrode (Au/PPy/GCE). Field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS) and powder X-ray diffraction (XRD) techniques were used for characterization of the composite. As an electrochemical sensor, the Au/PPy/GCE exhibited strongly catalytic activity toward the oxidation of hydrazine and hydroxylamine. The kinetic parameters such as the electron transfer coefficient (α) and charge transfer rate constant (k) for the oxidation of hydrazine and hydroxylamine were determined utilizing cyclic voltammetry (CV). The diffusion coefficient (D) of both two species was also estimated using chronoamperometry. Furthermore, the linear range, current sensitivity and detection limit for hydrazine and hydroxylamine were evaluated by differential pulse voltammetry (DPV). The detection limit of hydrazine and hydroxylamine was 0.20 and 0.21 μM (s/n = 3), respectively. In addition, the sensor showed excellent sensitivity, selectivity, reproducibility and stability properties.