Fabrication of Highly Oriented Ultrathin Zirconium Metal‐Organic Framework Membrane from Nanosheets towards Unprecedented Gas Separation

• Published in: Angewandte Chemie Vol. 135; no. 15
• Main Authors: Sun, Yanwei, Yan, Jiahui, Gao, Yunlei, Ji, Taotao, Chen, Sixing, Wang, Chen, Lu, Peng, Li, Yanshuo, Liu, Yi
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 03-04-2023
• Subjects: Carbon dioxide; Chemistry; Crystallography; Diffusion barriers; Epitaxial growth; Etching; Fabrication; Gas Separation; Membranes; Metal-organic frameworks; MOF Membrane; Nanosheets; Orientation; Performance enhancement; Reluctance; Seeds; Selectivity; Thickness; Zirconium
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202216697

Concurrent regulation of crystallographic orientation and thickness of zirconium metal–organic framework (Zr‐MOF) membranes is challenging but promising for their performance enhancement. In this study, we pioneered the fabrication of uniform triangular‐shaped, 40 nm thick UiO‐66 nanosheet (NS) seeds by employing an anisotropic etching strategy. Through innovating confined counter‐diffusion‐assisted epitaxial growth, highly (111)‐oriented 165 nm‐thick UiO‐66 membrane was prepared. The significant reduction in thickness and diffusion barrier in the framework endowed the membrane with unprecedented CO2 permeance (2070 GPU) as well as high CO2/N2 selectivity (35.4), which surpassed the performance limits of state‐of‐the‐art polycrystalline MOF membranes. In addition, highly (111)‐oriented 180 nm‐thick NH2‐UiO‐66 membrane showing superb H2/CO2 separation performance with H2 permeance of 1230 GPU and H2/CO2 selectivity of 41.3, was prepared with the above synthetic procedure.
Highly oriented sub‐200‐nm‐thick UiO‐66 and NH2‐UiO‐66 metal–organic framework membranes showed unprecedented CO2/N2 and H2/CO2 separation performances, respectively. Their formation was aided by the preparation of uniform triangular‐shaped UiO‐66 nanosheet seeds via anisotropic etching, confined counter‐diffusion‐assisted epitaxial growth, and the use of a ZrS2 source during epitaxial growth.