Use of carbon supports with copper ion as a highly sensitive non-enzymatic glucose sensor

•A new non-enzyme glucose sensing system is developed using carbon material-modified electrode and Cu2+ ion.•It is demonstrated to show high sensitivity (2,149 mA M−1 cm−2 on carbon paper), low detection limit, large linear range, and high stability.•The sensitivity and linear range can be tuned by the applied potential, Cu2+ concentration, and carbon material type.•By anchoring nanomolar Cu2+ ions on the carbon support, a practical glucose sensor of ultra-high sensitive (1,732 mA M−1 cm−2) is demonstrated. Nearly all current non-enzymatic electrochemical glucose sensors involve carefully designed metal/metal oxide nanomaterials and the complications of preparing electrocatalyst increase the fabrication cost and reduce the reproducibility of a sensor. Thus, a simple yet reliable and cost-effective glucose sensing system is much desired. Inspired by the glucose oxidation mechanism of copper-based nanomaterials, we developed a series of highly sensitive electrochemical glucose sensors using micromol level Cu2+ ions as an electrocatalyst. High sensitivities are achieved on various carbon-based electrodes (GCE: 614 mA M−1 cm−2; activated carbon: 1627 mA M−1 cm−2; carbon paper: 2149 mA M−1 cm−2; graphite powder: 1695 mA M−1 cm−2, and functionalized multi-walled carbon nanotube: 1842 mA M−1 cm−2). With short response time (