A highly sensitive non-enzymatic glucose electrode based on truncated octahedral CuO-modified Cu2O@Cu composite

A highly sensitive non-enzymatic glucose electrode based on truncated octahedral CuO-modified Cu2O@Cu composite was fabricated by a simple hydrothermal method combined with a two-step liquid-phase reduction process. Research on utilizing nanostructures to increase the contact opportunities between electroactive materials and target analytes, thereby enhancing electrocatalytic activity, is currently insufficient. In this study, we employed a reduction method to create a core–shell structure with copper shells encapsulating internal nanomaterials. This structure was designed to provide more active sites for glucose molecules, thereby enhancing the electrocatalytic response current of glucose. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the morphology and components of the products obtained from each step, while the CuO/Cu2O@Cu ternary composites were specifically analyzed using transmission electron microscopy (TEM). For glucose detection, CuO/Cu2O@Cu composite was modified onto a glassy carbon electrode (GCE) as a working electrode for electrochemical performance testing. The cyclic voltammetry (CV) test results indicate that the CuO/Cu2O@Cu-GCE electrode exhibits a sensitivity of 771 μA cm−2 mM−1 within the glucose concentration range of 0 to 10 mM, with a detection limit of 3.39 μM. Chronoamperometry (CA) results demonstrate that the electrode achieves a sensitivity of 1067 μA cm−2 mM−1 in the glucose concentration range of 0 to 1 mM, with a detection limit of 0.56 μM. Exhibiting a broad linear response range, high sensitivity, minimal detection limit, and robust selectivity against common interferents, the electrode maintained 99 % stability over four days and retained more than 85 % of its current response for two weeks, also showing notable sensitivity in artificial sweat samples. Owing to its simple fabrication, cost-effectiveness, and outstanding electrochemical properties, the CuO/Cu2O@Cu composite offers significant potential for application in non-enzymatic glucose sensing.