Fluoroalcohol-functionalized MXene for improved detection of sarin simulant

Abstract

Accurate and rapid detection of liquid-phase chemical warfare nerve agents (CWAs) such as Sarin remains a critical priority in environmental and defense applications. Two-dimensional MXenes comprising transition-metal carbides and nitrides have emerged as promising chemoresistive sensing materials owing to their metallic electronic properties and high density of pendant surface species. However, pristine MXenes exhibit limited specificity and adsorption capacity for effective organophosphates (OPs) detection. This study introduces diazonium hexafluoroisopropyl alcohol (HFIPA)-functionalized MXene (DHMX) for label-free electrochemical sensing of the Sarin simulant, dimethyl methylphosphonate (DMMP). The –(CF<inf>3</inf>)<inf>2</inf>C–OH moieties anchored on the MXene surface formed directional hydrogen bonds with the phosphoryl groups of DMMP, enabling enhanced molecular recognition. Owing to the synergistic effect of high surface area and tailored binding sites, DHMX exhibits significantly low detection limit (LOD = 0.012 pM), broad linear detection ranges (0.1–6 pM and 0.01 nM–1 µM), and high sensitivity (∼490 µA nM−1 cm−2), and outperforms pristine MXene (LOD ∼40 pM; sensitivity ∼165.9 µA nM−1 cm−2). This study presents the potential of surface-functionalized MXenes as a high-performance platform for liquid-phase electrochemical sensing of hazardous OPs.