CuS/PANI/GR conductive network with enhanced interfacial charge transfer for non-enzymatic glucose sensing

A CuS/PANI/GR nanocomposite was developed for non-enzymatic glucose sensing and food-related glucose monitoring. This nanocomposite was synthesized through a facile solvothermal method followed by in situ polymerization. Structural and chemical characterization studies revealed that hexagonal CuS was incorporated into polyaniline (PANI) and graphene (GR) nanosheets, forming a hierarchical conductive network. The introduction of PANI and GR effectively suppressed the aggregation of CuS nanosheets, moderately increased the BET surface area, improved the accessibility of electroactive sites, and favored interfacial electron transfer. Benefiting from the synergistic effect of this ternary architecture, where CuS provides abundant active sites, GR provides long-range electron transport pathways, and PANI regulates interfacial coupling and charge transfer between CuS and GR, the CuS/PANI/GR-modified electrode exhibited enhanced electrocatalytic activity toward glucose oxidation. At 0.65 V, the sensor achieved a wide linear range of 0.005-9.82 mM, a sensitivity of 2118 µA mM^-1 cm^-2, and a detection limit of 1.6 µM. Additionally, the sensor showed good operational stability, acceptable storage stability with 88.1% response retention after 15 days, and satisfactory reproducibility. This sensor was successfully applied to glucose detection in commercial beverage samples (milk, iced black tea, Sprite, and latte) with recoveries of 96.5-101.8%. This work demonstrates the role of conductive polymer/carbon networks in regulating interfacial charge transfer and glucose oxidation behavior of CuS-based electrodes.