Impedimetric detection of 2,4,6-trinitrotoluene using surface-functionalized halloysite nanotubes

Herein, we report the application of amine-surface-functionalized halloysite nanotubes (HAs) as active materials for the quantitative detection of 2,4,6-trinitrotoluene (TNT). The findings indicated that HA could selectively capture TNT via a strong reaction between the amine groups on its surface and the TNT molecules. Plate electrodes were fabricated from HA to evaluate its TNT-sensing capacity by electrochemical impedance spectroscopy. Upon binding with TNT, the proton conductivity on the HA plate electrodes increased linearly with the TNT concentration from 1.0 × 10^-11 M to 1.0 × 10^-4 M. The HA plate electrodes exhibited good sensitivity with a detection limit of 1.05 × 10^-12 M. Subsequently, the cycling measurements of the TNT binding/removal were performed on the HA plate electrode, and the material exhibited high stability, good regenerative ability, and good reversibility without a significant decrease in efficiency. The present work highlights the significant application potential of HAs for the electrochemical detection of TNT.