Ab-initio study of molybdenum carbide (Mo2C) as an adsorption-based filter

Highlights: • Adsorption of various poisonous gas molecules on various locations of molybdenum carbide monolayer is investigated. • A versatile gas sensing response is noticed for NO and NO₂ gas molecules. • Our results present a conceptual foundation for designing of Mo₂C based gas sensor. Motivated by recent research on adsorption properties of TMCs employed in gas sensing channels, we investigate the adsorption of various poisonous gas molecules (H₂S, SO₂, CO, NH₃, NO, NO₂) on various locations of molybdenum carbide (Mo₂C) monolayer using density functional theory (DFT). Novel gas sensing characteristics were exhibited by the molybdenum carbide sensors which have not been unveiled by foregoing typical sensing materials. Adsorption energy, adsorption distance, Bader charge, and recovery time are calculated. All the molecules, except NH₃ at the Carbon atom and hollow (H_o) site of the monolayer, are chemisorbed on the Mo₂C monolayer with high adsorption energies and apparent charge transfer. The electronic properties of Mo₂C monolayer before and after the adsorption of gas molecules are analyzed. Furthermore, a versatile gas sensing response is noticed for NO and NO₂ gas molecules with higher adsorption energies −3.508 eV and −5.933 eV respectively. Moreover, due to their high adsorption energies and structural stability, TMCs can be availed as channel materials for sensors.