Theoretical study of the interaction of SF6 molecule on Ti3C2Tx surfaces.

[Display omitted] • SF 6 and Ti 3 C 2 (OH) 2 surface have strong interaction during adsorption process. • Structure of SF 6 changes obviously with low-fluorine sulfide formed as a result of chemical adsorption. • Ti 3 C 2 T x terminated by hydroxyl is potential to be a catalyst for SF 6 decomposition. At present, searching for efficient methods to degrade sulfur hexafluoride (SF 6) is a worldwide hotspot. Due to the abundant active groups on the surface, MXene is regarded as an ideal catalyst support. In this paper, the potential active sites of Ti 3 C 2 T x (T = OH, F, O) for SF 6 degradation were studied using density functional theory (DFT) method. The results show the adsorption of SF 6 on Ti 3 C 2 (OH) 2 is significantly stronger than that on Ti 3 C 2 F 2 and Ti 3 C 2 O 2. Among typical adsorption sites on Ti 3 C 2 (OH) 2 , SF 6 exhibited the strongest interaction at OH-1 site. Complex electron orbital interactions occurred between SF 6 and Ti 3 C 2 (OH) 2. Adsorption energy reached −6.739 eV and about 1.414e transferred from Ti 3 C 2 (OH) 2 to SF 6. Structure of SF 6 changed obviously and chemical adsorption occurred in this process. However, on Ti 3 C 2 F 2 and Ti 3 C 2 O 2 , gas–solid interactions were weak and the structures had little change, which was mainly physical adsorption. Compared with common catalysts such as Ag, α ‑Al 2 O 3 and BaTiO 3 , Ti 3 C 2 (OH) 2 showed better catalytic activity for SF 6 degradation. By strong adsorption of the active site on the surface, the degradation products were separated from each other, which weakened SF 6 recombination and promoted the further degradation. The results provide theoretical support for MXene acting as a catalyst to efficiently degrade SF 6. [ABSTRACT FROM AUTHOR]