Highly sensitive shape dependent electro-catalysis of TNT molecules using Pd and Pd–Pt alloy based nanostructures

Abstract

This study demonstrates the fabrication of a highly sensitive electrochemical sensor designed for the quantification of 2,4,6-trinitrotoluene (TNT). The devised sensor system relies on the electro-catalytic reduction of TNT molecules achieved at the surface of palladium (Pd) and palladium-platinum (Pd–Pt) alloy nanostructure modified glassy carbon electrodes (GCEs). The electrode based reduction was studied in a competitive manner with Pd nanocubes (Pd NCs) in comparison to Pd hollow nanospheres (Pd HNS) and Pd–Pt alloy nanostructures (Pd–Pt NA). The experiments revealed Pd NCs to possess high catalytic capability in comparison to their other competitors where relatively greater signal sensitivity suggested the importance of shape-dependence electro-catalysis. The Pd NCs based sensor was found to be highly sensitive towards TNT molecules with detection limits up to 0.01 ppm and a working window of 0.1–7.0 ppm. Moreover, the Pd NCs based sensor demonstrated excellent selectivity in the presence of other common nitro-aromatic compounds. In addition, the excellent recoveries obtained in the real matrix environment (tap water) further promise the real-time application of the developed sensor for trace level detection of TNT.