Preparation of reduced graphene oxide/Cu nanoparticle composites through electrophoretic deposition: application for nonenzymatic glucose sensing

The paper reports on the simultaneous reduction/deposition of reduced graphene oxide/copper nanoparticles (rGO/Cu NPs) on a glass/Ti/Au electrode using an electrophoretic deposition (EPD) technique from a colloidal suspension of graphene oxide (GO) and copper sulphate (CuSO4) in ethanol. The method allows controlling the nanoparticle density by adjusting the deposition time. Structural characterization and chemical composition analysis of the modified electrode showed the simultaneous reduction of GO with the concomitant deposition of metallic CuNPs with a Cu(OH)(2) shell. The electrocatalytic activity of the modified electrode was evaluated for non-enzymatic glucose sensing in alkaline medium. While the Au electrode modified only with rGO did not show obvious electrocatalytic activity, the electrode coated with rGO/CuNPs exhibited excellent electrocatalytic behavior towards glucose oxidation with a high sensitivity of 447.65 mu A mM(-1) cm(-2). The response current of the sensor is linear to glucose concentrations up to 1.2 mM with a detection limit of 3.4 mu M. Furthermore, the interference from various oxidizable molecules such as dopamine, uric acid, ascorbic acid and carbohydrate molecules such as fructose, lactose and galactose was negligible, indicating a good selectivity of detection. The application of this glucose sensor in real samples has also been demonstrated successfully.