A Sensitive Electrochemical Platform Based on Co/Co9S8/Nitrogen-Doping Carbon for Portable Glucose Detection

Abstract

Non-enzymatic electrochemical glucose sensors represent attractive alternatives to conventional enzyme-based devices; however, their practical performance is often limited by insufficient exposure of active sites and sluggish interfacial charge-transfer kinetics. Herein, a heterostructured Co/Co₉S₈/nitrogen-doped carbon (Co/Co₉S₈/NC) composite is rationally constructed using ZIF-67 as a sacrificial template through sequential high-temperature pyrolysis and controlled sulfidation. Benefiting from the synergistic integration of metallic Co, Co₉S₈, and a conductive N-doped carbon matrix, the resulting Co/Co₉S₈/NC electrode exhibits markedly enhanced electrocatalytic activity toward glucose oxidation in alkaline media. The sensor delivers a high sensitivity of 174.38 µA mM⁻¹ cm⁻², a wide linear detection range of 0.2–16 000 µM, and a low detection limit of 0.12 µM, along with excellent selectivity, reproducibility, and long-term stability. Furthermore, by integrating the electrode into a smartphone-assisted portable electrochemical platform, reliable glucose detection in serum samples is achieved. This work demonstrates the effectiveness of MOF-derived heterostructure engineering for constructing high-performance Co-based electrocatalysts and highlights their strong potential for portable non-enzymatic glucose monitoring.

Graphical Abstract