Fast and sensitive analysis of explosive compounds using Co₃O₄–MnO₂@MWCNTs nanocomposite integrated electrochemical sensing platform

Fast and accurate determination of toxic and explosives compounds are necessary. Thus, a portable-electrochemical sensing system was developed for the rapid and sensitive detection of 2,4,6-trinitrotoluene (TNT) using a screen-printed electrode (SPE) modified with a Co₃O₄/MnO₂@MWCNTs nanocomposite. This nanocomposite combines the electrocatalytic activity of the hybrid metal oxides (Co₃O₄ and MnO₂) with the high conductivity and surface area of multi-walled carbon nanotubes (MWCNTs), resulting in enhanced sensor performance. The modified SPE exhibited excellent electrocatalytic activity towards TNT voltammetric reduction, showing a well-defined voltammetric response. Electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated the improved electron transfer kinetics and reduced charge transfer resistance at the modified electrode. Differential pulse voltammetry (DPV) was employed for quantitative TNT detection, achieving a linear response in the concentration range of 0.33 to 50 ppm with a detection limit of 0.153 ppm. The sensor demonstrated good selectivity against common interferents and other nitroaromatic compounds. Furthermore, the newly developed sensor surface exhibited satisfactory stability and reproducibility, making it a promising candidate for on-site and real-time TNT detection in environmental and security applications.