Interfacial Electronic Modulation and Sensing Mechanisms of CO, C ₂ F ₄ , and COF ₂ on MO x -Modified V ₂ CF ₂ MXene for C ₄ F ₇ N Decomposition Gas Monitoring

To meet the demand for online monitoring of fault byproducts generated from eco-friendly insulating gases in electrical equipment, density functional theory (DFT) calculations were performed to investigate CO, C 2 F 4, and COF 2 adsorption on NiO-, TiO 2 -, and MoO 3 -modified V 2 CF 2 MXene. All oxide modifiers form thermodynamically stable MO x /V 2 CF 2 interfaces and significantly regulate the electronic properties of V 2 CF 2 . Adsorption results reveal distinct oxide-dependent selectivity. CO exhibits the strongest adsorption on NiO–V 2 CF 2 ( E ads = −1.490 eV), while NiO modification also enhances interactions with fluorinated gases, giving adsorption energies of −0.817 eV for C 2 F 4 and −0.687 eV for COF 2 . Density-of-states analysis indicates evident interfacial orbital hybridization and charge redistribution after gas adsorption. Desorption kinetics and ab initio molecular dynamics (AIMD) analyses demonstrate favorable cyclic recoverability within practical temperature windows. NiO–V 2 CF 2 enables rapid COF 2 recovery at 298 K (τ = 0.411 s) and room-temperature recoverability for C 2 F 4 (τ = 65.9 s), whereas CO regeneration is fastest on TiO 2 –V 2 CF 2 at 398 K (τ = 7.27 s) and remains feasible on MoO 3 –V 2 CF 2 at 298 K (τ = 110 s). These results provide theoretical guidance for MXene-based sensing materials for eco-friendly insulating-gas monitoring.