Two-in-One MOF Structure with Tunable Porosity for Enhanced Separation
Guanxing Li, Yu Han
Abstract
Microporous crystalline materials, such as zeolites and metal–organic frameworks (MOFs), possess well-defined cavities and channels of molecular dimensions. While these micropores offer unique molecular sieving properties, their small size (usually <1.5 nm) constrains molecular diffusion within crystals, thereby limiting their efficiency in separation and catalytic applications. Introducing mesopores (2–50 nm) or macropores (>50 nm) in microporous crystals would facilitate intracrystalline molecular diffusion, but there is a lack of effective methods to achieve this goal for MOF crystals. In this issue of ACS Central Science, Gu and coauthors report a novel metal–organic framework solid solution (MOSS) strategy that enables the homogeneous mixing of microporous MOF NU-901 and mesoporous MOF NU-1000, with tunable ratios, in single nanocrystals. (1) When used as gas chromatography stationary phases for separation of various isomers, the MOSS nanocrystals exhibit unique elution sequences and significantly enhanced separation resolution compared to single-component MOF nanocrystals.