Potential NO2 gas-sensing performance of (Cr, Mo, W)-doped VO-Ti3C2O2-MXenes: a first-principles study

Abstract Typical Ti 3 C 2 O 2 MXenes materials have been widely studied in the field of gas sensors due to their excellent properties in optoelectronics. The adsorption properties of four gases (NO 2 , NO, NH 3 , H 2 O) on the intrinsic Ti 3 C 2 O 2 , Ti 3 C 2 O 2 with oxygen vacancy (V O -Ti 3 C 2 O 2 ) and (Cr, Mo, W) doped V O -Ti 3 C 2 O 2 were studied by density functional theory (DFT). The geometric structure, molecular dynamics, adsorption energy, differential charge density, and band structure of four gas molecules (NO 2 , NO, NH 3 , H 2 O) adsorbed in the intrinsic Ti 3 C 2 O 2 , V O -Ti 3 C 2 O 2 , and (Cr, Mo, W) doped V O -Ti 3 C 2 O 2 were analyzed systematically. The results show that the adsorption energy and charge transfer properties of the V O -Ti 3 C 2 O 2 doped with Cr, Mo, W are stronger than those of the intrinsic Ti 3 C 2 O 2 . Among them, the maximum adsorption energy of W-doped Ti 3 C 2 O 2 for NO 2 adsorption is −7.67 eV. Therefore, the inclusion of metal atoms in Ti 3 C 2 O 2 material can improve the adsorption and selectivity of NO 2 and other gases. In addition, W-doped Ti 3 C 2 O 2 MXenes is a promising material for NO 2 gas detection.