DFT study of sensing properties of defected and transition-metal doped V2CF2 towards CH4.

As a new type of gas sensor, MXenes material is of great significance in indoor harmful gas detection. The geometric, electronic, and magnetic properties of CH 4 adsorbed on intact, F-vacancy defected, and transition-metal (TMs: Mn, Co, Ni, Zn, Nb, Mo) doped V 2 CF 2 have been investigated based on density functional theory. Perfect V 2 CF 2 and F-vacancy defected substrates exhibited low charge transfer, long adsorption distance, and small adsorption energy for CH 4. The adsorption mechanism was physical adsorption. After introducing Co and Ni dopants, the adsorption mechanism of CH 4 changed to be chemisorption. Additionally, the asymmetric electron spin distribution between the dopant and V atom caused the substrate to change from being non-magnetic to magnetic, as shown by the electronic density of states diagrams. The hybridization between TM-3d orbitals and the p orbitals of the CH 4 molecule significantly improved the adsorption stability. It is hoped that the results could provide ideas for creating new CH 4 gas sensors based on MXenes. • The adsorption of CH 4 on intact V 2 CF 2 and F-vacancy defected V 2 CF 2 is physical adsorption. • The introduction of F-vacancy enhanced the adsorption stability of CH 4 molecule. • The doping of transition-metal atoms (Mn, Co, Ni, Nb, Mo) significantly improves the adsorption stability of CH 4 gas. • The adsorption of CH 4 on Co- and Ni-doped systems is chemical adsorption. • The F-vacancy defected V 2 CF 2 doped with Ni can be used to detect the presence of CH 4. [ABSTRACT FROM AUTHOR]