A novel nonenzymatic amperometric hydrogen peroxide sensor based on CuO@Cu2O nanowires embedded into poly(vinyl alcohol).

A new, very simple, rapid and inexpensive nonenzymatic amperometric sensor for hydrogen peroxide (H2O2) detection is proposed. It is based on the immobilization of cupric/cuprous oxide core shell nanowires (CuO@Cu2O-NWs) in a poly(vinyl alcohol) (PVA) matrix directly drop casted on a glassy carbon electrode surface to make a CuO@Cu2O core shell like NWs PVA embedded (CuO@Cu2O-NWs/PVA) sensor. CuO nanowires with mean diameters of 120-170nm and length in the range 2-5μm were grown by a simple catalyst-free thermal oxidation process based on resistive heating of pure copper wires at ambient conditions. The oxidation process of the copper wire surface led to the formation of a three layered structure: a thick Cu2O bottom layer, a CuO thin intermediate layer and CuO nanowires. CuO nanowires were carefully scratched from Cu2O layer with a sharp knife, dispersed into ethanol and sonicated. Then, the NWs were embedded in PVA matrix. The morphological and spectroscopic characterization of synthesized CuO-NWs and CuO@Cu2O-NWs/PVA were performed by transmission electron microscopy (TEM), selected area diffraction pattern (SAD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. Moreover a complete electrochemical characterization of these new CuO@Cu2O-NWs/PVA modified glassy carbon electrodes was performed by Cyclic Voltammetry (CV) and Cronoamperometry (CA) in phosphate buffer (pH=7; I=0.2) to investigate the sensing properties of this material against H2O2. The electrochemical performances of proposed sensors as high sensitivity, fast response, reproducibility and selectivity make them suitable for the quantitative determination of hydrogen peroxide substrate in batch analysis.