Recent developments in Metal-organic framework-based mixed matrix membranes for hydrogen separation

Membrane separation is one of the low-energy hydrogen purification technologies that effectively mitigates the carbon footprint and is eco-friendly process for large-scale integration. Conventional membranes, such as polymeric ones, typically suffer from the trade-off between permeability and selectivity demonstrated by the Robeson's upper bound. Metal organic frameworks (MOFs) are recognized as promising fillers to fabricate the mixed matrix membranes (MMMs) for hydrogen separation due to their high porosity, large internal surface area, and structural tunability. Herein, this review offers a comprehensive summary of the related literature that explores the challenges in developing MMMs, and presents an in-depth discussion on fabrication and modification strategies of MOF-based MMMs specifically for H2/N2, H2/CH4, and H2/CO2 separation. Advanced characterization techniques for understanding membrane properties, specifically the MOF-polymer interface, are outlined. Subsequently, the hydrogen separation performance of MOF-based MMMs under harsh operating conditions and improvement in robustness and long-term durability properties are emphasized. The outlook and future directions for MOF-based MMMs are also proposed. It is anticipated that this review will serve as a stepping stone for the coming MOF-based MMMs research on sustainable and large-scale application for hydrogen separation.