Flexible self-supported non-enzymatic sensors based on metal sulfides/CuO nanocomposites for efficient glucose detection

Designing low-cost, preparation-simple and flexible self-supported non-enzymatic glucose sensing electrodes provides great promise for batch preparation and realistic applications of portable glucose sensors. Both transition metal oxide-based and transition metal sulfide-based glucose sensors exhibit good electrocatalytic properties and high electron transfer rates, and combining them will result in glucose sensors with higher electrocatalytic activity and sensitivity. In this work, nitrogen-doped carbon cloths (NCCs) modified with metal sulfides/CuO nanocomposites were obtained as flexible self-supported non-enzymatic sensing electrodes (NiCu-S/CuO/NCC) by hydrothermal and successive ionic layer adsorption reaction methods. The effects of growth time and Ni/Cu molar ratio in the growth solution on the electrochemical properties of nanocomposites were discussed. The CuO nanorods prepared by hydrothermal method had good electrocatalytic activity, while the introduction of metal sulfides improved the conductivity of sensing materials and increased the active sites. As a flexible non-enzymatic glucose sensing electrode, NiCu-S/CuO/NCC showed significant sensitivity (5.103 mA mM^-1 cm^-2), low limit of detection (0.30 μM) and good selectivity, demonstrating the great potential of constructing metal sulfides/CuO for glucose sensing applications.