Iron oxide; Nanocomposite; Nanochips; Ultrasonication; Electrochemical sensor

In this study, bare iron oxide nanochips (NCs), carbon-supported iron oxide nanochips (C@alpha-Fe2O3), and glutathione-supported C@alpha-Fe2O3 nanocomposite (Glu/C@alpha-Fe2O3) were synthesized. As-synthesized materials were inspected using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and a UV-visible absorption approach. Physical investigations confirmed the synthesis of rhombohedral phased alpha-Fe2O3, whereas FESEM certified nanosized material formation. Voltammetry and impedance studies were used to evaluate and compare the electrochemical sensing activities. The electrochemical behavior of the Glu/C@alpha-Fe2O3 nanohybrid was investigated using differential pulse voltammetry (DPV) to identify their sensitivity towards 2-nitrophenol (2-NP) and 4nitrophenol (4-NP). The stability of the square wave voltammetry SWV signals was detected in the range of 50-0.05 mu M for both 2-NP and 4-NP. All electrochemical factors that influence the effectiveness of the developed sensors, including pH of the medium, accumulation time, and the influence of supporting electrolytes were thoroughly investigated. The sensor-based on our prepared electroactive material demonstrated remarkable electrocatalytic activity and good conductivity with a broad linear range, a low detection limit and high sensitivity for nitrophenol isomer reduction. We also tested the sensor for practical applications in water samples. These results showed that the suggested method could be used in the future to detect potentially dangerous environmental pollutants in water samples.