tert‐Butyl Functionalized Ultra‐Microporous Three‐Dimensional Covalent Organic Framework for Efficient SF₆/N₂ Separation

Efficient capture and recovery of sulfur hexafluoride (SF 6 ) from SF 6 /N 2 mixtures is critical for mitigating greenhouse effects and promoting gas recycling in the electronics industry. Herein, we report a novel ultra‐microporous three‐dimensional covalent organic framework (COF), termed CPOF‐12, enriched with tert ‐butyl groups. CPOF‐12 exhibits a Brunauer−Emmett−Teller (BET) surface area of 1,140 m 2 g −1 , a pore volume of 0.66 cm 3 g −1 , and a uniform pore size of 0.59 nm, which closely matches the kinetic diameter of SF 6 (0.52 nm). Gas adsorption measurements reveal a high SF 6 uptake of 2.20 mmol g −1 at 298 K and 1 bar, along with an exceptional SF 6 /N 2 selectivity of 149.4, calculated using ideal adsorbed solution theory (IAST). This study highlights the effectiveness of pore surface engineering in COFs for high‐performance separation of greenhouse gases.