Mingled MnO₂ and Co₃O₄ Binary Nanostructures on Well-Aligned Electrospun Carbon Nanofibers for Nonenzymatic Glucose Oxidation and Sensing

Abstract

This work reports on uniformly mingled nanostructures of Co3O4 and MnO2 deposited on a well-aligned electrospun carbon nanofiber (WA-ECNF) mat for rapid glucose electrooxidation and sensing. The hybridization of Co3O4 and MnO2 is synthesized by a simple one-step and template-free electrodeposition technique with a constant low current at 60 μA for 3 h at room temperature in an aqueous solution. The binary MnO2/Co3O4@WA-ECNF nanomatrix electrode exhibits excellent uniformity with high porosity, increased electrochemically active surface areas and conductivity, fast charge transfer, and improved efficiency for glucose electrooxidation in comparison to the monometallic MnO2 or Co3O4 at the WA-ECNFs. The electrochemical performance of the MnO2/Co3O4@ECNF electrode is characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). The MnO2/Co3O4@ECNF electrode shows superior sensing characteristics including a rapid glucose oxidation response within 5 s, a wide range of detection from 5 μM to 10.9 mM, an excellent sensitivity of 1159 μA mM–1 cm–2, and a detection limit of 0.3 μM (S/N = 3) with satisfactory selectivity, great reproducibility, and stability. These results are discussed with mechanisms of glucose absorption to the nanostructure surfaces followed by a fast glucose oxidation reaction.