State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, China.
Advanced Membranes and Porous Materials (AMPM) Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia.
Nat Mater. 2023 Jun;22(6):769-776. doi: 10.1038/s41563-023-01541-0. Epub 2023 May 11.
Metal-organic framework (MOF) membranes are energy-efficient candidates for molecular separations, but it remains a considerable challenge to eliminate defects at the atomic scale. The enlargement of pores due to defects reduces the molecular-sieving performance in separations and hampers the wider application of MOF membranes, especially for liquid separations, owing to insufficient stability. Here we report the elimination of lattice defects in MOF membranes based on a high-probability theoretical coordination strategy that creates sufficient chemical potential to overcome the steric hindrance that occurs when completely connecting ligands to metal clusters. Lattice defect elimination is observed by real-space high-resolution transmission electron microscopy and studied with a mathematical model and density functional theory calculations. This leads to a family of high-connectivity MOF membranes that possess ångström-sized lattice apertures that realize high and stable separation performance for gases, water desalination and an organic solvent azeotrope. Our strategy could enable a platform for the regulation of nanoconfined molecular transport in MOF pores.
金属-有机骨架（MOF）膜是用于分子分离的节能候选材料，但在原子尺度上消除缺陷仍然是一个相当大的挑战。由于缺陷导致的孔径增大降低了分离过程中的分子筛性能，并阻碍了 MOF 膜的更广泛应用，特别是对于液体分离，因为其稳定性不足。在这里，我们报告了基于高概率理论配位策略的 MOF 膜中晶格缺陷的消除，该策略创造了足够的化学势来克服完全将配体连接到金属簇时发生的空间位阻。通过实空间高分辨率透射电子显微镜观察到晶格缺陷的消除，并通过数学模型和密度泛函理论计算进行了研究。这导致了一系列具有高连接性的 MOF 膜，这些膜具有埃级别的晶格孔径，实现了气体、海水淡化和有机溶剂共沸物的高稳定分离性能。我们的策略可以为调节 MOF 孔中纳米受限分子输运提供一个平台。
