Size-Matching-Driven SF6 Capture Via Isoreticular Pore Contraction in a Microporous MOF.

Efficient capture of sulfur hexafluoride (SF6) from dilute mixtures remains a critical challenge. Herein, we demonstrate a size-matching strategy via isoreticular pore contraction in a microporous MOF, where the pore aperture is reduced from ∼9 Å to ∼6 Å by ligand substitution. The resulting confined pore environment in Zn(NDC)(TED)0.5 acts as a molecular clamp for SF6, leading to a nearly 4-fold enhancement in uptake, from 12 to 47 cm3 g-1 at 0.1 bar, and a remarkable enhancement in SF6/N2 selectivity from 74 to 558. Enhanced adsorption enthalpy, IAST analysis, and breakthrough experiments confirm superior separation under dilute conditions, while GCMC simulations reveal localized adsorption within confined pockets. This work highlights pore contraction as an effective strategy for high-performance SF6 capture.