ZIF-L membrane with a membrane-interlocked-support composite architecture for H₂/CO₂ separation

Metal-organic framework (MOF) membranes hold great promise in energy-efficient chemical separations. The outstanding challenges of the microstructural design stem from (1) thinning of membranes to immensely reduce the mass-transfer resistance (for high permeances); (2) tuning of orientation to optimize the selective transport of gas molecules, and (3) reinforcement of intercrystalline structure to subside leakage through defective gaps (for high selectivity). Here, we propose the ZIF-L membrane that is completely confined into the voids of the alumina support through an interfacial assembly process, producing an appealing membrane-interlocked-support (MIS) composite architecture that meets the requirements of the microstructural design of MOF membranes. Consequently, the membranes show average H₂ permeances of above 4000 GPU and H₂/CO₂ separation factor (SF) of above 200, representing record-high separation performances of ZIF-L membranes and falling into the industrial target zone (H₂ permeance > 1000 GPU and H₂/CO₂ SF > 60). Furthermore, the ZIF-L membrane possessing the MIS composite architecture that is established with alumina particles as scaffolds shows mechanical stability, scraped repeatedly by a piece of silicon rubber causing no selectivity loss.