Abstract Developing sustainable and cost-effective electrode materials are critical for advancing enzyme-free glucose sensing technologies. In this study, a novel hybrid nanocomposite containing copper nanowires (CuNWs) and iron-oxide functionalized biochar (Fe-BC) was synthesized to fabricate a high-performance electrochemical sensor. The Fe-BC was derived from hazelnut shells via phosphoric acid-assisted pyrolysis at 500 °C, followed by iron chloride (FeCl₂) treatment to incorporate redox-acti