Au@Cu2O core-shell structure for high sensitive non-enzymatic glucose sensor

A novel and sensitive non-enzymatic glucose sensor was developed based on the modification of Au@Cu2O nanocomposite on the surface of glassy carbon (Au@Cu2O/Nafion/GC) electrode. Au@Cu2O nanocomposites were prepared using a facile chemical reduction method and its core-shell structure was confirmed by transmission electron microscopy (TEM) and element analyses, in which the diameter of Au nanoparticle (NP) is about 14 nm and the thickness of shell is about 30-50 nm, being composed of Cu2O nanoparticles. Electrochemical properties of Au@Cu2O/Nafion/GC electrode were investigated by cyclic voltammetric techniques and electrochemical impedance spectroscopy (EIS). It was found that the Au@Cu2O/Nafion/GC electrode exhibited enhanced electrocatalytic activity towards glucose oxidation in alkaline medium (pH = 12.6), as compared to those of Cu2O/Nafion/GC and Au/Nafion/GC electrodes. Some influence parameters including pH value and Au@Cu2O content on electrocatalytic activity of the modified electrode have been investigated. Under the optimized conditions, the electrochemical sensor has a linear dependence over glucose concentrations from 0.05 to 2.0 mM with a sensitivity of 715 μA mM−1 Cm−2. Moreover, such a glucose sensor demonstrated good stability, reproducibility and selectivity. Our results suggest that Au@Cu2O core-shell structure could be a promising candidate for the construction of non-enzymatic sensor.