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

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Explosive detection remains a critical challenge in security and environmental monitoring.
• Conventional detection methods often lack sensitivity, selectivity, or portability.
• Halloysite nanotubes (HAs) offer a versatile platform for developing novel sensing materials.

Purpose of the Study:

• To develop and evaluate amine-surface-functionalized halloysite nanotubes (HAs) for the quantitative electrochemical detection of 2,4,6-trinitrotoluene (TNT).
• To investigate the sensing mechanism and performance characteristics of HA-based electrodes for TNT detection.

Main Methods:

• Amine-functionalization of halloysite nanotubes.
• Fabrication of HA-based plate electrodes.
• Electrochemical impedance spectroscopy (EIS) for TNT detection.
• Evaluation of sensitivity, detection limit, stability, and reversibility.

Main Results:

• HA exhibited selective capture of TNT through amine group interactions.
• Proton conductivity on HA electrodes increased linearly with TNT concentration (1.0 × 10^-11 M to 1.0 × 10^-4 M).
• Achieved a low detection limit of 1.05 × 10^-12 M for TNT.
• Demonstrated high stability, regenerative ability, and reversibility over multiple cycles.

Conclusions:

• Amine-functionalized HAs are effective active materials for sensitive and quantitative electrochemical TNT detection.
• The developed HA-based sensor shows significant potential for practical applications in TNT sensing.
• The material's stability and reusability support its use in repeated detection scenarios.