Exploring the Gas Sensing Performances of O-Functionalized TiVC MXene: Mechanistic Insights from Computations

The detection of toxic gases remains a critical challenge for environmental safety, and MXenes have rapidly emerged as innovative materials for sensor development. In this work, we break new ground by exploring the sensing capabilities of O-functionalized TiVC MXene, a material not yet studied for gas sensing applications. Ab initio molecular dynamics (AIMD) simulations confirm the monolayer's dynamical stability at 300 K. Using first-principles-based DFT calculations, we systematically analyze the interaction of H2, CO, NO, NO2, and SO2 gas analytes with the TiVCO2 surface. Our study highlights key parameters such as adsorption strength, charge transfer, change in work function, and gas desorption time, critical to sensitivity and selectivity-core elements of the 4-S principle (sensitivity, selectivity, stability, and speed). The robust interaction energies (≤-48 kJ mol-1), short interaction distances, and significant charge transfer suggest that NO adsorption on TiVCO2 is characterized by strong physisorption, governed by hybridization of the 3d-orbitals of titanium and vanadium with the p-orbital of nitrogen. Notably, the change in work function upon interaction comes out to be >0.1 eV and the calculated desorption time of NO at 300 K is 1.74 s, making this MXene a highly promising candidate for NO gas detection at room temperature. Other gases exhibited much weaker physisorption with nanosecond desorption times, reinforcing the selective nature of TiVCO2 for NO detection. These findings offer insights into the use of O-functionalized TiVC MXene for gas sensors, with the potential to revolutionize the design of high-performance sensing devices in environmental monitoring and industrial applications.