One-step wet-chemical synthesis of ternary ZnO/CuO/Co3O4 nanoparticles for sensitive and selective melamine sensor development

Using one-step wet-chemically synthesized ternary ZnO/CuO/Co3O4 nanoparticles (NPs), a sensitive chemical sensor was developed to detect melamine selectively using an electrochemical approach in a phosphate buffer solution. The calcined ZnO/CuO/Co3O4 NPs were investigated using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), ultraviolet visible spectroscopy (UV-vis), and Fourier-transform infrared spectroscopy (FTIR). To fabricate the melamine sensor, a slurry of NPs in ethanol was deposited as a uniform thin layer on a glassy carbon electrode (GCE). The calibration curve of the proposed melamine sensor in the form of current versus concentration (in logarithmic scale) plot is found to be linear over a melamine concentration range of 0.05 nM-0.05 mM. The sensitivity of the sensor is very good (36.98 μA μM-1 cm-2) and the detection limit is very low (9.7 ± 0.5 pM). The melamine sensor with active ZnO/CuO/Co3O4 NPs shows good reliability, precise reproducibility and a short response time in sensing performances. The developed ternary metal oxide nanoparticle based sensor is a new introduction in sensor technology for determining melamine in environmental samples reliably.