The Adsorption and Preliminary Degradation Performance of SF6 on Mixed Terminal Ti2CTx: A DFT Study

Considering the excellent insulation and arc extinguishing characteristics, strong greenhouse gas SF 6 is widely used in power equipment like Gas Insulated Substation (GIS) and Gas Insulated Transmission Line (GIL). Searching for an efficient SF6 degradation treatment has been a hotspot. With abundant active terminals on the surface, two-dimensional MXene has a considerable catalytic application prospect. Herein, gas-solid adsorption configurations were constructed based on $\mathrm{Ti}_{2} \mathrm{CT}_{\mathbf{I}}(\mathrm{T}=\mathrm{OH}, \mathrm{F}, \mathrm{O})$ MCene with complete terminal of one type and mixed terminals of three different average site occupancies. Density Functional Theory (DFT) calculations including adsorption energy, charge transfer, deformation charge density and density of states (DOS) were carried out to analyze the potential active sites on $\mathrm{Ti}_{2} \mathrm{CT}_{\mathrm{I}}$ for SF 6 catalytic degradation. Results showed that hydroxyl groups possessed strong activity for preliminary degradation of SF 6 . On the $\mathrm{Ti}_{2} \mathrm{CT}_{\mathbf{I}}$ surface containing 44 % hydroxyl groups, SF 6 had a chemisorption behavior and then degraded to form SF 4 and HF. The adsorption energy reached -1.138eV level and about 0.901 electrons transferred from the surface to SF 6 . This study provides theoretical support for MXene as a catalyst for SF6 degradation.