Electrodeposition of copper oxide/polypyrrole/reduced graphene oxide as a nonenzymatic glucose biosensor

We report the synthesis and application of copper oxide/polypyrrole nanofiber/reduced graphene oxide nanocomposite (CuxO/Ppy/rGO/GCE) for the detection of glucose (GLC). CuxO, Ppy and rGO were synthesized via electrodeposition process. The formation of the rGO and Ppy were approved by Fourier Transform Infrared Spectroscopy (FT-IR). Energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) confirmed the formation of copper oxide. The field emission scanning electron microscopy (FESEM) images depicted the existence of wrinkle rGO, Ppy nanofibers with diameter around 100 nm and the uniformity of the CuxO particles deposited on the Ppy nanofibers. Electrochemical impedance spectroscopy (EIS) data also indicated the charge transfer of each layer decreased compared to the underneath layer. By using cyclic voltammetry (CV) and chronoamperometry under pH 7.2, the electrocatalytic activity of CuxO/Ppy/rGO/GCE toward GLC was explored. The sensor presented a linear range of 0.1-100 mM (R2 = 0.991) of GLC, that is higher than most of the present nonenzymatic glucose biosensors based on CuxO, Ppy and rGO. The limit of detection (LOD) reaches 0.03 μM (at S/N = 3). Additionally, the sensor exhibited remarkable reproducibility, stability and selectivity properties which make CuxO/Ppy/rGO/GCE a good nonenzymatic GLC sensor.