Fabrication of Cu@Ag core-shell/nafion/polyalizarin: Applications to simultaneous electrocatalytic oxidation and reduction of nitrite in water samples

In this study, a Cu@Ag core-shell was synthesized using a co-precipitation method. To create a new electrochemical sensor, a Cu@Ag core-shell with conductive polymers such as polyalizarin yellow R (PA) and Nafion (Nf) was immobilized on the surface of a glassy carbon electrode (Cu@Ag-Nf/PA/GCE). X-ray diffraction analysis (XRD), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR) techniques were employed to characterize the Cu@Ag-Nf/PA/GCE. This modified electrode was used to measure nitrite ions in the water samples. Electrochemical analysis of nitrite was conducted using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) methods. For the first time, the results indicated that the Cu@Ag-Nf/PA nanocomposite demonstrated excellent performance in simultaneously electrocatalyzing oxidation at two specific potentials (0.17V and 0.98V denoted as OX1 and OX2 peaks) and one reduction potential (-0.42 V as a Red peak) for nitrite ions. This research showed various advantages, including applications in linear ranges, sensitivities, and detection limits in three potential areas (OX1, OX2, and Red) by elucidating the mechanism of action of the new electrode for detecting nitrite ions in water samples.