Chlorine-terminated Titanium Carbide MXene as Nitrogen Oxide Gas Sensor: A First-Principles Study

A first-principles study was employed to investigate the gas sensing properties of chlorine-terminated titanium carbide (Ti
2
CCl
2
) MXene. Using density functional theory (DFT) calculations, the adsorption energy (E
ads
), the density of states (DOS), and charge density difference isosurfaces were analyzed to understand the interactions between nitrogen oxide (NO) gas molecule and the Ti
2
CCl
2
MXene. A lattice constant of 3.22 Å was obtained for the Ti
2
CCl
2
MXene. The Eads for the most favorable configuration of the NO molecule physisorption on the Ti
2
CCl
2
MXene was calculated as -0.50 eV. DOS calculations demonstrated that the adsorption of the NO molecule on the Ti
2
CCl
2
MXene introduced new states close to the Fermi energy level, which can modulate the electronic properties of the Ti
2
CCl
2
MXene, significantly. In addition, the iso-surfaces representation of charge density difference supported the charge transfer from the NO molecule to the Ti
2
CCl
2
MXene. The detailed first- principles study of the Ti
2
CCl
2
MXene and its gas sensing properties is analyzed and reported in this paper.