Development of an ultra-sensitive para-nitrophenol sensor using tri-metallic oxide MoO2·Fe3O4·CuO nanocomposites

Abstract

A tri-metal oxide, MoO₂·Fe₃O₄·CuO (TMO), was synthesized by the co-precipitation method and characterized by XRD, SEM-EDS, and FTIR. The average particle size of the nanocomposite was found to be 34.85 nm. The zeta potential and hydrodynamic size of the MoO₂·Fe₃O₄·CuO nanocomposite were studied in acidic and basic pH respectively. A glassy carbon electrode (GCE) was modified by MoO₂·Fe₃O₄·CuO to develop a chemical sensor for para-nitrophenol (p-NP). A simple I–V method was employed for this study. Excellent sensitivity, an ultra-low detection limit, long-term stability, and reproducibility of the MoO₂·Fe₃O₄·CuO/Nafion/GCE sensor were observed towards p-NP. A linear calibration plot (r²: 0.9995) was obtained for 1.0 pM to 0.01 mM aqueous p-NP solution, with a sensitivity value of 5.2430 μA μM⁻¹ cm⁻² and remarkably low detection limit (LOD) of 0.2 pM.