Simultaneous and Selective Electrochemical Determination of Catechol and Hydroquinone on A Nickel Oxide (NiO) Reduced Graphene Oxide (rGO) Doped Multiwalled Carbon Nanotube (fMWCNT) Modified Platinum Electrode

A new electrochemical sensor is reported based on a modified platinum (Pt) electrode sequentially drop-casting doped with functionalized multi-walled carbon nanotubes (fMWCNTs) decorated by reduced graphene oxide (rGO) and nickel oxide (NiO) nanoparticles (NPs). The NiO/rGO/fMWCNTs nanohybrid was characterized by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). This sensor was employed for the simultaneous determination of catechol and hydroquinone. In the cyclic voltammetry (CV) results for a binary mixture of catechol and hydroquinone, the peak potentials of the two dihydroxybenzene isomers were separated by more than 105 mV, demonstrating the ability of the fabricated sensor to simultaneously determine the analytes. The NiO/rGO/fMWCNTs/Pt electrode exhibited a wide linear range of 10–300 μM with detection limits of 19.86 and 40.18 nM based upon a signal-to-noise ratio of 3 for catechol and hydroquinone, respectively. Furthermore, using differential pulse voltammetry (DPV), the sensor maintained well-defined peaks, demonstrating suitable selectivity. In addition, the NiO/rGO/fMWCNTs/Pt nanocomposite exhibits stability values of 92.3% and 91.6% for catechol and hydroquinone with excellent repeatability. The sensor analyzed water samples with spike recoveries from 90% to 106.66% for catechol and 88% to 98.66% for hydroquinone, respectively.