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

Abstract 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 CO 2 permeance (2070 GPU) as well as high CO 2 /N 2 selectivity (35.4), which surpassed the performance limits of state‐of‐the‐art polycrystalline MOF membranes. In addition, highly (111)‐oriented 180 nm‐thick NH 2 ‐UiO‐66 membrane showing superb H 2 /CO 2 separation performance with H 2 permeance of 1230 GPU and H 2 /CO 2 selectivity of 41.3, was prepared with the above synthetic procedure.