Bridging-patching c-pores with tetrafluorosuccinate in a csq-type mesoporous Zr-MOF with different crystal dimensions: cycling stability and adsorption kinetics for in-door humidity control

Abstract

Metal–organic frameworks (MOFs) are promising for energy-efficient indoor humidity control, yet their long-term cycling stability is crucial. While Zr-MOFs featuring specific structural parameters—one-dimensional channels with neighbouring coplanar Zr₆ clusters spaced below 5.4 Å—typically demonstrate high hydrolytic stability due to restricted water accessibility, exceptions exist. The framework NU-1008, although meeting these criteria, shows sub-optimal cycling stability due to hydrolysis of its c-pore formate ligands, which compromises structural integrity. To address this, a Solvent Assisted Ligand Incorporation (SALI) strategy is employed to install auxiliary ligands within its c-pore. Modification with tetrafluorosuccinate (TFS) yields NU-1008-TFS, which exhibits exceptional stability, retaining 97.7% of its initial water uptake after four cycles and 99.4% of its original surface area. The derived bulk single-crystal material, NU-1008-SC-TFS, integrates this high stability with a substantial water capacity (0.80 g g⁻¹) and rapid kinetics (0.34 mg g⁻¹ s⁻¹), positioning it as a promising candidate adsorbent for an intelligent humidity management system.