Ma Xixi, Wan Zheng, Li Yanhong, He Xiao, Caro Jürgen, Huang Aisheng
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, 200241, Shanghai, China.
Institute of Physical Chemistry and Electrochemistry, Leibniz University, Hannover, Germany.
Angew Chem Int Ed Engl. 2020 Nov 16;59(47):20858-20862. doi: 10.1002/anie.202008260. Epub 2020 Sep 11.
Control of the microstructure grain orientation, grain boundaries and thickness are crucial for MOF membranes. We report a novel synthesis strategy to prepare highly c-oriented ZIF-95 membranes through vapor-assisted in-plane epitaxial growth. In a mixed DMF/water vapor atmosphere, in-plane epitaxial growth of a ZIF-95 seeds layer was achieved to obtain an oriented and well-intergrown ZIF-95 membrane with a thickness of only 600 nm. Demonstrated by both experimental and simulation studies, the c-oriented ZIF-95 membrane displayed superior separation performance because a perfectly oriented structure resulted in a notable reduction of intercrystalline defects and transport pathways. For the separation of equimolar binary mixtures at 100 °C and 1 bar, the mixture separation factors of H /CO and H /CH were 32.2 and 53.7, respectively, with an H permeance of over 7.9×10 mol m s Pa , which was 4.6 times higher than that of a randomly oriented ZIF-95 membrane.
控制金属有机框架（MOF）膜的微观结构、晶粒取向、晶界和厚度至关重要。我们报道了一种新颖的合成策略，通过气相辅助面内外延生长制备高度c取向的ZIF-95膜。在二甲基甲酰胺（DMF）/水蒸气混合气氛中，实现了ZIF-95籽晶层的面内外延生长，从而获得了厚度仅为600 nm的取向良好且生长紧密的ZIF-95膜。实验和模拟研究均表明，c取向的ZIF-95膜表现出优异的分离性能，因为完美的取向结构显著减少了晶间缺陷和传输通道。对于在100°C和1 bar下的等摩尔二元混合物分离，H₂/CO和H₂/CH₄的混合物分离因子分别为32.2和53.7，H₂渗透率超过7.9×10⁻⁷ mol·m⁻²·s⁻¹·Pa⁻¹，比随机取向的ZIF-95膜高4.6倍。
