Nano-composite of Co3O4 and Cu with enhanced stability and catalytic performance for non-enzymatic electrochemical glucose sensors

Abstract

Nanostructured Co₃O₄ with near-cubic morphology was synthesised using the solvothermal method, and a non-enzymatic electrochemical glucose sensor (Co₃O₄–CuNPs/Pt) was successfully constructed by dropping and potentiostatic depositing technologies. The obtained Co₃O₄ and Co₃O₄–CuNPs were characterised and investigated by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Quantitative analysis of glucose was performed using the amperometric (i–t) method, and a plot of current difference versus concentration of glucose was linear in the range 0.5–336 μM, with a linear correlation coefficient (R²) of 0.9989 and limit of detection (LOD) of 0.43 μM. When the linear range was reduced to 0.5–76.5 μM, R² and LOD were 0.9997 and 0.17 μM, respectively. The sensitivity of the sensor was evaluated as 3.58 × 10⁴ and 4.03 × 10⁴ μA μM⁻¹ cm⁻² for the above two linear ranges, respectively. This novel sensor produced satisfactory reproducibility and stability and was applied to monitor trace amounts of glucose in human serum samples.