Rapid Synthesis of Ultramicroporous Potassium-Pyrenetetracarboxylate Framework with Confined-Space-Charge-Driving CO₂ Capture

Upgrading and optimizing carbon capture technology and materials may significantly enhance the development of industry. Herein, a specific confined-space-charge-driving CO 2 capture strategy is pioneered in a MOF adsorbent, SNNU-117, an anionic potassium-pyrenetetracarboxylate complex obtained via a simple, mild, rapid, and scalable salting-out method. As expected, the regularly shaped ultramicropores (about 3.6 Å) comparable to those of CO 2 molecules effectively restrict gas molecule reorientation, while the multiple active protons on the pore surface provide a positive electrostatic potential for polarized oxygen in CO 2 molecules. Such synergy between pore size and electrostatic potential clearly promotes the CO 2 adsorption and separation performance. Under 298 K, 1 bar, SNNU-117 exhibits high affinity for CO 2 with exceptional IAST selectivity of CO 2 /C 2 H 2 (2744), CO 2 /N 2 (6.3 × 10 4 ), and CO 2 /CH 4 (5.6 × 10 6 ) surpassing nearly all MOF adsorbents. Density functional theory (DFT) calculation, Grand Canonical Monte Carlo (GCMC) simulation, and dynamic breakthrough experiments further support the specific confined-space-charge-driving CO 2 capture ability of SNNU-117.