Ultrafast one-pot anodic preparation of Co3O4/nanoporous gold composite electrode as an efficient nonenzymatic amperometric sensor for glucose and hydrogen peroxide

For fabrication of composite electrode, one-pot strategy is highly attractive for convenience and efficiency. Here, a self-supporting Co3O4/nanoporous gold (NPG) composite electrode was one-pot prepared via one-step in situ anodization of a smooth gold electrode in a CoCl2 solution within 100 s. It worked as a bifunctional electrocatalyst for glucose oxidation and H2O2 reduction in NaOH solution. Under optimized conditions, the electrocatalytic oxidation of glucose exhibits a wide linear range from 2 mu M to 2.11 mM with a limit of detection as low as 0.085 mu M (SIN = 3) and an ultrahigh sensitivity of 4470.4 mu A mM(-1)cm(-2). Detection of glucose in human serum samples are also realized with results comparable to those from local hospital. The electrocatalytic reduction of H2O2 shows a linear response range from 20 mu M to 19.1 mM and a high sensitivity of 1338.7 mu A mM(-1)cm (-2). The present results demonstrate that the facilely prepared Co3O4/NPG is a promising nonenzymatic sensor for rapid amperometric detection of glucose and H2O2 with ultrasensitivity, high selectivity, satisfactory reproducibility, good stability and long duration. (C) 2019 Elsevier B.V. All rights reserved.