CuO/Co₃O₄@Co₃O₄/g-C₃N₄ screen-printed portable electrochemical sensor for non-enzymatic glucose detection

The development of high-performance glucose sensors is of great significance for blood glucose monitoring and diabetes management. In this work, we designed and synthesized a novel nanocomposite electrocatalyst featuring hierarchical yolk–shell structured CuO/Co₃O₄@Co₃O₄ hybridized with graphitic carbon nitride (g-C₃N₄). The electrocatalytic performance for glucose oxidation was significantly enhanced by optimizing the mass ratio of the CuO/Co₃O₄@Co₃O₄ yolk–shell nanocubes to g-C₃N₄. The optimized composite electrode (with a 5:1 mass ratio) demonstrated exceptional sensing with an ultra-fast response (2 s) and recovery (4 s), outstanding reproducibility and excellent anti-interference capability. When engineered into a screen-printed electrode platform, this sensor achieved a sensitivity of 0.12 μA/(μM·cm²) with a wide linear detection range from 0.001 to 2.0 mM. Density functional theory (DFT) calculations reveal that the combination of CuO and Co₃O₄ can break the charge symmetry on Co atoms, enhance the material’s activity, as well as stronger adsorption for glucose, accelerating the accumulation of target molecules on the sensor surface during detection. Furthermore, a portable sensing device was successful developed by integrating this fabricated sensor with a miniaturized potentiostat. The superior electrocatalytic activity of CuO/Co₃O₄@Co₃O₄/g-C₃N₄ nanocomposite establishes a highly promising candidate for non-enzymatic glucose sensing technologies.