Self-Supported Cu/Fe₃O₄ Hierarchical Nanosheets on Ni Foam for High-Efficiency Non-Enzymatic Glucose Sensing

Electrochemical glucose sensors are vital for clinical diagnostics and the food industry, where accurate detection is essential. However, the limitations of glucose oxidase (GOx)-based sensors, such as complex preparation, high cost, and environmental sensitivity, highlight the need for non-enzymatic sensors that directly oxidize glucose at the electrode surface. In this study, a self-supporting hierarchical Cu/Fe₃O₄ nanosheet electrode was successfully fabricated by in situ growth on Ni Foam using a hydrothermal method, followed by annealing treatment. The Cu/Fe₃O₄ hierarchical nanosheet structure, with its large surface area, provides abundant active sites for electrocatalysis, while the strong interactions between Cu/Fe₃O₄ and Ni Foam enhance electron transfer efficiency. This novel electrode structure demonstrates exceptional electrochemical performance for non-enzymatic glucose sensing, with an ultrahigh sensitivity of 12.85 μA·μM^-1·cm^-2, a low detection limit of 0.71 μM, and a linear range extending up to 1 mM. Moreover, the Cu/Fe₃O₄/NF electrode exhibits excellent stability, a rapid response (~3 s), and good selectivity against interfering substances such as uric acid, ascorbic acid, H₂O₂, urea, and KCl. It also shows strong reliability in analyzing human serum samples. Therefore, Cu/Fe₃O₄/NF holds great promise as a non-enzymatic glucose sensor, and this work offers a valuable strategy for the design of advanced electrochemical electrodes.