Cuprous oxide microspheres on graphene nanosheets: An enhanced material for non-enzymatic electrochemical detection of HO and glucose

We report here a facile one-step green synthesis of cuprous oxide microspheres (CuOMS) on reduced graphene oxide (RGO) by reducing Cu ions and GO with sodium ascorbate synchronously in the presence of sodium hydroxide. CuOMS with different sizes on the surface of RGO were successfully synthesized by adjusting the mass ratio of GO to CuSO·5HO in this reaction system. It was found that uniform CuOMS were formed on RGO by increasing the mass ratio from 1:20 to 1:80. The synthesized CuOMS-RGO composites with different structures were immobilized onto glassy carbon electrodes and applied to construct electrochemical hydrogen peroxide (HO) and glucose sensors. The results indicate that the CuOMS-RGO composite created with the mass ratio of 1:80 presents the best sensor performances. The fabricated HO sensor exhibits a fast amperometric response to HO with a linear detection range from 0.005 to 2.775 mM and a detection limit of 0.0108 mM, and the glucose sensor has a linear detection range from 0.001 to 0.419 mM and a detection limit of 7.288 × 10 mM. The superior performance is ascribed to the unique structure of the synthesized CuOMS and the excellent conductivity of the RGO content. In addition, the synthesized CuOMS-RGO composites exhibited improved electrochemical stability. Such novel CuOMS-RGO hybrid materials represent promising non-enzymatic electrochemical glucose and HO sensors with high sensitivity and selectivity, improved stability, and fast amperometric response.