Hydrothermal deposition of CuO/rGO/Cu2O nanocomposite on copper foil for sensitive nonenzymatic voltammetric determination of glucose and hydrogen peroxide

A nanocomposite consisting of CuO, reduced graphene oxide (rGO) and Cu2O nanoparticles was hydrothermally and in-situ deposited on a copper foil. The composite contains 3 kinds of interfaces, namely CuO/rGO, rGO/Cu2O and Cu2O/Cu. This facilitates redox reactions to occur between graphene oxide and the copper foil, and also leads to electrostatic attraction between the positively charged copper ions and negatively charged rGO. This, in turn, leads to improved electron and ion transfer. The modified foil is shown to directly act as a sensor for amperometric detection of both glucose (at 0.65 V vs SCE) and hydrogen peroxide (at -0.3 V). Figures of merit for sensing glucose (in 0.1 M NaOH) include (a) an ultrahigh sensitivity of 3401 A mu A center dot mM(-1)center dot cm(-2), (b) a limit of detection as low as 0.10 mu M, (c) a linear detection range extends from 0.5 mu M to 8.3 mM, and (d) a response time of < 0.5 s. As for sensing hydrogen peroxide (at pH 7), the sensitivity is 366.2 A mu A center dot mM(-1)center dot cm(-2), the limit of detection is 0.05 mu M, the linear range extends from 0.5 mu M to 9.7 mM, and the response time is 0.8 s.