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

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.