Oriented growth of large-area metal-organic framework ZIF-8 membrane for hydrogen separation

Optimal orientation is the key factor to optimize the gas separation performance of metal-organic framework (MOF) membranes. However, it is still greatly challenging to prepare large-area oriented MOF membranes for industrial applications. Herein, we prepared compact and (100) oriented zeolitic-imidazolate framework-8 (ZIF-8) membranes with membrane area up to 500 cm 2 on the graphite substrate via support-induced strategy within 2 h. With membrane thickness of only 620 nm, the (100) oriented ZIF-8 membranes exhibit high gas separation performances due to the reduction of inter-crystalline defects and permeation resistance. At 100 °C and 1 bar, the separation factors of H 2 /CO 2 , H 2 /CH 4 and H 2 /C 3 H 8 are 18.5, 58.2 and 101.6, respectively, with H 2 permeance of about 160 x 10 −9  mol m −2  s −1 ·Pa −1 . The different positions of the 500 cm 2 ZIF-8 membrane show complete consistency in orientation and separation performance, recommending this membrane suitable for future industrial applications. Further, also oriented ZIF-67 and MOF-303 membranes can be consistently prepared by this strategy, confirming its versatility for the preparation of large-area MOF membranes.