Sensing properties of defective and transition metal-doped Ti₂CF₂ toward C₂H₂: a DFT study

Abstract In this study, we systematically investigated the potential of transition metal (TM)-doped Ti 2 CF 2 as a sensor for acetylene (C 2 H 2 ) gas using first-principles calculations. Owing to the introduction of F-vacancies and TM doping, the adsorption performance of Ti 2 CF 2 toward C 2 H 2 was significantly enhanced. Ti 2 CF 2 with Nb and Mo doping exhibited optimal adsorption capacity and stability, making them promising candidates for high-performance C 2 H 2 gas sensors. Analysis of the adsorption energy, charge transfer, and density of states revealed that the underlying mechanism of TM doping on C 2 H 2 adsorption was enhanced electron transfer, increased adsorption energy, and orbital hybridization, which strengthened interactions between the C 2 H 2 molecule and the Ti 2 CF 2 substrate. This study provides a theoretical basis for designing novel high-performance gas sensors.