Ultrafast one-pot anodic preparation of Co 3 O 4 /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 Co3 O4 /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 H2 O2 reduction in NaOH solution. Under optimized conditions, the electrocatalytic oxidation of glucose exhibits a wide linear range from 2 μM to 2.11 mM with a limit of detection as low as 0.085 μM (S/N = 3) and an ultrahigh sensitivity of 4470.4 μA 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 H2 O2 shows a linear response range from 20 μM to 19.1 mM and a high sensitivity of 1338.7 μA mM-1  cm-2 . The present results demonstrate that the facilely prepared Co3 O4 /NPG is a promising nonenzymatic sensor for rapid amperometric detection of glucose and H2 O2 with ultrasensitivity, high selectivity, satisfactory reproducibility, good stability and long duration.