Highly sensitive detection of gallic acid based on 3D interconnected porous carbon nanotubes/carbon nanosheets modified glassy carbon electrode

Carbon materials have great significance to improve the detection performance of electrochemical sensors. It is still a great challenge to prepare the carbon-based gallic acid (GA) electrochemical sensor with excellent detection performance based on a simple, economical and scalable synthetic strategy. In this work, we fabricated a highly sensitive GA electrochemical sensor by modifying the glassy carbon electrode (GCE) with a hybrid carbon composite of 3D interconnected porous carbon nanotubes/carbon nanosheets (3D IPCNT/CNS) for the first time. The hybrid carbon composite was prepared via a scalable ball-milling strategy followed by thermal decomposition. The whole synthesis process did not involve the use of template and complex morphology control process. In this hybrid carbon material, carbon nanotubes and carbon nanosheets were integrated into a 3D interconnected hierarchical porous structure, which served as a conductive network with large specific surface area and surface functional groups. These advantages provided sufficient electrolyte-electrode interface, facilitated the electron transport, and enhanced the surface affinity for GA at the interface between the modified electrode and electrolyte. The fabricated 3D IPCNT/CNS/GCE sensor showed satisfactory linear relationship between peak current and GA concentration in the broad range of 0.05−20 μM with relatively low detection limit of 0.016 μM and limit of quantification of 0.053 μM (S/N=3). Moreover, the fabricated sensor exhibited good reproducibility, high stability, and excellent selectivity. A satisfactory GA recovery and detection in green tea as well as black tea suggested practical application possibility of the 3D IPCNT/CNS/GCE sensor for highly sensitive determination of GA.