A non-enzymatic hydrogen peroxide sensor based on a glassy carbon electrode modified with cuprous oxide and nitrogen-doped graphene in a nafion matrix

We have modified a glassy carbon electrode (GCE) with copper(I) oxide nanoparticles (NPs), nitrogen-doped graphene (N-graphene) and Nafion to obtain a novel sensing platform for the non-enzymatic detection of hydrogen peroxide. The deposition of the Cu2O NPs on N-graphene was accomplished by single-step chemical reduction. The nanocomposite was characterized by using X-ray diffraction and scanning electron microscopy which revealed the successful attachment of monodispersed Cu2O NPs to the N-graphene. Electrochemical studies revealed that the composite possesses excellent electrocatalytic activity toward the reduction of H2O2 in pH 7.4 phosphate buffer solution at a working potential of -0.60 V. Nafion obviously enhances the stability of the modified GCE and repels any negatively charged species. Compared to a conventional Cu2O/Nafion-modified GCE, the modified GCE presented here exhibits (a) a higher catalytic activity for the reduction of H2O2 (1.94 times), (b) a wider linear range (from 5.0 mu M to 3.57 mM), (c) a lower detection limit (0.8 mu M at an S/N of 3), (d) higher sensitivity (26.67 mu A mM(-1)) and (e) a shorter response time (2 s). Moreover, the new GCE exhibits good selectivity and stability. These properties make the new hybrid electrode a promising tool for to the development of electrochemical sensors, molecular bioelectronic devices, biosensors, and biofuel cells.