An improved sensitivity non-enzymatic ascorbic acid sensor based on a Ag2O nanowire modified Ag electrode

In this paper, the Ag2O nanowires had been prepared and applied for the fabrication of ascorbic acid sensors with high enhanced sensitivity by using self-assembly technology. The structures and morphologies of Ag2O nanowires were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The direct electrocatalytic oxidation of ascorbic acid in alkaline medium at Ag2O nanowires modified electrodes had been investigated in detail and the condition for determination of ascorbic acid was optimized, such as support-electrolyte, pH and scan speed. The oxidation peak current changed linearly with the concentration of ascorbic acid over the range from 2.0×10-8 mol/L to 1.0 mmol/L, and the detection limit can reach 1.0×10-8mol/L. Compared to a bare Ag electrode, a substantial decrease in the overvoltage of the ascorbic acid oxidation was observed at the Ag nanowires electrodes with oxidation starting at ca. 0.7V vs. Ag/AgCl (saturated KCl). The Ag2O nanowires modified electrode allows highly sensitive, low working potential, stable, and fast amperometric sensing of ascorbic acid, thus is promising for the future development of non-enzymatic ascorbic acid sensors.