Molybdenum Carbide MXenes as Efficient Nanosensors toward Selected Chemical Warfare Agents

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 defense, chemical sensing, healthcare, and safe environmental monitoring units. Particularly, efficient detection of chemical warfare agents (CWAs) is of great importance for human safety and security. Inspired by this, we explored molybdenum carbide MXenes (Mo2CT x ; T x = O, F, and S) as efficient sensors toward selected CWAs, such as arsine (AsH3), mustard gas (C4H8Cl2S), cyanogen chloride (NCCl), and phosgene (COCl2) both in aqueous and non-aqueous media. Our calculations based on van der Waals-corrected density functional theory (DFT) revealed 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 resulted in comparatively weak bindings of −0.29 to −0.58 eV. We further reported the variations in the electronic properties, electrostatic potentials, and work functions of Mo2CT x upon the adsorption of CWAs, which authenticated an efficient sensing mechanism toward CWA detection. Statistical thermodynamic analysis was applied to explore the sensing properties of Mo2CT x at various temperatures and pressures. These 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.

Oxidation of Molybdenum-Based Single-Metallic/bimetallic Carbide MXenes in Aqueous Suspensions: Mechanistic Insights

“…MXenes are two-dimensional (2D) metal carbides, nitrides, and carbonitrides with the general formula M n +1 X n T x , where M is an early transition metal, such as Ti, Mo, V, Nb, and Ta; X denotes carbon and/or nitrogen; T x represents surface functional groups (such as −OH, =O, and −F); and n = 1–4. − MXenes are derived from three-dimensional (3D) M n +1 AX n (MAX)-phase crystals by selective chemical etching of “A” elements such as Al, Si, or Ga under strongly acidic or basic conditions. ,− MXenes exhibit a unique combination of properties, such as excellent metallic conductivity, − strong hydrophilicity, ,, considerable flexibility, , tunable surface chemistry, and adjustable electronic characteristics. − Consequently, they are promising materials for various applications including energy storage and conversion, , − electromagnetic interference shielding, − water purification, , catalysis, − thermoelectricity generation, , and sensing. − …”

Identification of Lung Cancer Biomarkers by Nanosensors Based on Titanium Carbide (Ti3C2Tx) MXenes

“…Bestowed with unique electrical, electronic, optical, and transport properties, two-dimensional (2D) nanostructures have emerged as promising candidates in numerous scientific fields, including nanoelectronics, optoelectronics, spintronics, battery-energy materials, sensing, and even in biomedical applications. − These single to few atom thick layered 2D structures, with high aspect ratios, tuned band gaps, and high surface reactivities are the most attractive candidates for sensing various toxic gas molecules, VOCs, chemical warfare agents (CWAs), and various biological molecules. , Various graphene-like 2D materials with tweaked electronic properties are being reported as efficient materials for sensing toxic gases. , Besides, beyond graphene with high carrier mobility and ionic conductivity, , various 2D transition metal dichalcogenides, − and the modeled sheets from group 15 materials like bismuthene, phosphorene, and arsenene, are investigated progressively for their sensing propensity toward various toxic gases and biomolecules.…”

2D Molybdenum Carbide MXene Cocatalyst: Synthesis, Modification, and Photocatalysis

“…Different from the accordion-like structure of other MXenes, the as-fabricated Mo 2 C MXene with a hexagonal crystal structure is consisted of thick lamellae stacked together by Van der Waals forces. [56][57][58] Thus, additional exfoliation procedure is necessary to obtain dispersed single-layer Mo 2 C MXene (Figure 1B). [59,60] Generally, the as-obtained Mo 2 C MXene is composed of the gathered Mo-C-Mo layers through the interlinked Mo-C bonds, which endows Mo 2 C MXene with a typical nanosheet structure with superior physical character.…”