Microporous covalent organic frameworks for sulfur hexafluoride capture and separation

Sulfur hexafluoride (SF6) is the most potent greenhouse gas whose emission is in great need of reducing during the indus-trial processes. Here, a variety of covalent organic frameworks with varying topologies, surface areas, pore size distribu-tions is designed and synthesized for systematically studying structure-property relationships of COF-based SF6 adsor-bents. Surface area was found to be a prerequisite for achieving high SF6 uptakes, and small pore size at ca. 0.9 nm could effectively enhance the adsorbate-adsorbent interaction and hence the SF6/N2 selectivity. With a large specific surface area and a suitable pore size, RCOF-1 showed superior SF6 adsorption capacities up to 4.13 mmol g-1 and large SF6/N2 se-lectivity up to 125 (273 K, 100 kPa), which can be considered one of the most high-performance porous materials for SF6 capture and separation. This work not only provides a series of high-performance SF6 adsorbents, but also broadens the horizon of applications of the emerging COFs, pointing out their development direction in the field of SF6 capture and separation.