Adsorption Interface-Induced H...F Charge Transfer in Ultramicroporous Metal–Organic Frameworks for Perfluorinated Gas Separation
Yue Wu, Tong Yan, Wenxiang Zhang, Shu‐Hui Chen, Yu Fu, Zhonghui Zhang, Heping Ma
Abstract
Fluorinated electron gases (F-gases) are widely used in semiconductor manufacturing because of their unique plasma reactivity with silicon-based semiconductor materials. However, the low conversion efficiency of these F-gases in the plasma process makes the vent gases contain a certain concentration of F-gases, which causes environmental pollution and global warming. In this study, three ultramicroporous metal–organic frameworks M3(HCOO)6 (M = Co, Ni, Mn) were prepared for the separation and purification of F-gases through H...F interaction-induced charge transfer on the pore surface. Impressive F-gas adsorption capacities and record breakthrough selectivities for NF3/N2, CF4/N2, and SF6/N2 mixtures were achieved in M3(HCOO)6 MOFs. Density-functional theory (DFT) calculations and grand canonical Monte Carlo (GCMC) simulation studies demonstrated that the adsorption-induced charge exchange between the F atom in F-gases and the H atom in HCOO– accounts for the high performance of F-gases/N2 separation. Systematic experimental investigations including equilibrium gas adsorption, instant adsorption rates, and dynamic breakthrough experiments also confirmed the efficient performance of M3(HCOO)6 MOFs for F-gas capture.