Fabrication of Pillar‐Cage Fluorinated Anion Pillared Metal–Organic Frameworks via a Pillar Embedding Strategy and Efficient Separation of SO <sub>2</sub> through Multi‐Site Trapping
Wenli Xu, Liangjun Li, Mengwei Guo, Fuzhao Zhang, Pengcheng Dai, Xin Gu, Dandan Liu, Tao Liu, Kuitong Zhang, Tao Xing, Muzhou Wang, Zhi Li, Mingbo Wu
Abstract
Abstract Flue gas desulfurization is crucial for both human health and ecological environments. However, developing efficient SO 2 adsorbents that can break the trade‐off between adsorption capacity and selectivity is still challenging. In this work, a new type of fluorinated anion‐pillared metal–organic frameworks (APMOFs) with a pillar‐cage structure is fabricated through pillar‐embedding into a highly porous and robust framework. This type of APMOFs comprises smaller tetrahedral cages and larger icosahedral cages interconnected by embedded [NbOF 5 ] 2− and [TaOF 5 ] 2− anions acting as pillars. The APMOFs exhibits high porosity and density of fluorinated anions, ensuring exceptional SO 2 adsorption capacity and ultrahigh selectivity for SO 2 /CO 2 and SO 2 /N 2 gas mixtures. Furthermore, these two structures demonstrate excellent stability towards water, acid/alkali, and SO 2 adsorption. Cycle dynamic breakthrough experiments confirm the excellent separation performance of SO 2 /CO 2 gas mixtures and their cyclic stability. SO 2 ‐loaded single‐crystal X‐ray diffraction, Grand canonical Monte Carlo (GCMC) simulations combined with density functional theory (DFT) calculations reveal the preferred adsorption domains for SO 2 molecules. The multiple‐site host–guest and guest‐guest interactions facilitate selective recognition and dense packing of SO 2 in this hybrid porous material. This work will be instructive for designing porous materials for flue gas desulfurization and other gas‐purification processes.