Supplementary material from "Three-dimensional Co3O4@MWNTs nanocomposite with enhanced electrochemical performance for nonenzymatic glucose biosensors and biofuel cells"

Three-dimensional nanoarchitectures of Co₃O₄@multi-walled carbon nanotubes (Co₃O₄@MWNTs) were synthesized via a one-step process with hydrothermal growth of Co₃O₄ nanoparticles onto MWNTs. The structure and morphology of the Co₃O₄@MWNTs were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, scanning electron microscopy and transmission electron microscopy. The electrocatalytic mechanism of the Co₃O₄@MWNTs was studied by X-ray photoelectron spectroscopy and cyclic voltammetry. Co₃O₄@MWNTs exhibited high electrocatalytic activity towards glucose oxidation in alkaline medium and could be used in nonenzymatic electrochemical devices for glucose oxidation. The open circuit voltage of the nonenzymatic glucose/O₂ fuel cell was 0.68 V, with a maximum power density of 0.22 mW cm⁻² at 0.30 V. The excellent electrochemical properties, low cost, and facile preparation of Co₃O₄@MWNTs demonstrates the potential of strongly coupled oxide/nanocarbon hybrid as effective electrocatalyst in glucose fuel cells and biosensors.