Molybdenum Carbide MXenes as Efficient Nanosensors Towards Selected Chemical Warfare Agents

TL;DR

This study investigates molybdenum carbide MXenes as potential low-cost, reusable sensors for detecting highly toxic chemical warfare agents through computational analysis of their binding and electronic properties.

Contribution

It introduces the use of Mo2CTx MXenes as effective sensors for CWAs, demonstrating strong chemisorption and sensing mechanisms via DFT calculations and thermodynamic analysis.

Findings

Mo2CF2 and Mo2CS2 bind CWAs strongly with energies between -2.33 and -4.05 eV.

Mo2CO2 shows weaker binding energies of -0.29 to -0.58 eV.

Electronic property changes confirm the sensing potential of Mo2CTx materials.

Abstract

There has been budding demand for the fast, reliable, inexpensive, non-invasive, sensitive, and compact sensors with low power consumption in various fields, such as defence, chemical sensing, health care, and safe environment monitoring units. Particularly, an efficient detection of chemical warfare agents (CWAs) is of great importance for the safety and security of the humans. Inspired by this, we explored molybdenum carbide MXenes (Mo2CTx; Tx= O, F, S) as efficient sensors towards selected CWAs, such as arsine (AsH3), mustard gas (C4H8Cl2S), cyanogen chloride (NCCl), and phosgene (COCl2) both in aqueous and non-aqueous mediums. Our van der Waals corrected density functional theory (DFT) calculations reveal that the CWAs bind with Mo2CF2, and Mo2CS2 monolayers under strong chemisorption with binding energies in the range of -2.33 to -4.05 eV, whereas Mo2CO2 results in comparatively weak bindings of -0.29 to -0.58 eV. We further report the variations in the electronic properties, electrostatic potentials and work functions of Mo2CTx upon the adsorption of CWAs, which authenticate an efficient sensing mechanism. Statistical thermodynamic analysis is applied to explore the sensing properties of Mo2CTx at various of temperatures and pressures. We believe that our findings will pave the way to an innovative class of low-cost reusable sensors for the sensitive and selective detection of highly toxic CWAs in air as well as in aqueous media.