A Superhydrophobic Nanotrap Porous Organic Cage for Efficient Capture of SF ₆ Under Dry and Humid Conditions

ABSTRACT

Effective SF ₆ capture and recovery are essential for reducing greenhouse gas emissions and promoting resource recycling, yet many porous materials exhibit reduced separation performance for SF ₆ /N ₂ mixtures in humid environments due to water adsorption competition or structural instability. To address this challenge, we propose a “superhydrophobic nanotrap” strategy by designing a nitrogen‐rich superhydrophobic porous organic cage (POC) named IMUPOC‐DA. This material incorporates a moisture‐blocking shield of superhydrophobic isobutyl chains and an inner cavity with a π‐system and Lewis base sites that synergistically enhance SF ₆ trapping. At 298 K and 1 bar, IMUPOC‐DA achieves an SF ₆ adsorption capacity of 53.6 cm ³ g ⁻¹ and an SF ₆ /N ₂ uptake ratio of 20.02, a record‐high reported thus far for POC‐based adsorbents. More importantly, the superhydrophobic surface endows the material with an extremely low water uptake (72.1 mg g ⁻¹ ), a high water contact angle (150.11 ^° ), and excellent water stability. Dynamic column breakthrough experiments under 80% relative humidity show nearly unchanged SF ₆ breakthrough time compared with dry conditions, demonstrating outstanding SF ₆ /N ₂ separation performance even in a moist environment. Therefore, this work not only provides a high‐performance candidate for industrial SF ₆ recovery but also presents a general design strategy for developing moisture‐resistant adsorbents for gas separation.