Simultaneous Boost of SF ₆ Adsorption Capacity and Kinetics Through Isoreticular Functionalization of Zinc(II)‐Pyrazolate Frameworks

Abstract

ABSTRACT The capture of sulfur hexafluoride (SF 6 ), the most potent greenhouse gas, is of critical importance. Enhancement of dynamic SF 6 capture capacity presents significant challenges due to its chemical inertness and low concentration in industrial effluent streams. Herein, we demonstrate that the isoreticular functionalization of zinc‐pyrazolate metal‐organic frameworks (MOFs) enables simultaneous enhancement of both SF 6 adsorption capacity and uptake kinetics. Through replacement of benzene with pyridine in the ligand, BUT‐125 (BUT: Beijing University of Technology) achieves a record‐high SF 6 adsorption capacity of 3.57 mmol cm −3 at 0.1 bar and 298 K, representing a 27% improvement over its structural analogue Zn‐DPB (DPB: 1,3‐di(pyrazolate‐4‐yl)benzene). Density functional theory (DFT) calculations reveal that pyridine functionalization increases the positive charge density on hydrogen atoms within molecular trap sites, strengthening C─H···F interactions with SF 6 molecules. Remarkably, BUT‐125 also exhibits outstanding adsorption kinetics, that combined with high equilibrium uptake, leads to an exceptional dynamic SF 6 capture capacity of 3.42 mmol cm −3 from the SF 6 /N 2 (10/90) mixture, surpassing reported porous sorbents.