Interwoven MOF gel – polymer network mixed matrix membranes for enhanced H2/CO2 separation

Abstract

The scalable fabrication of large-area, defect-free metal-organic framework (MOF) membranes for precise gas separation is hindered by their intrinsic brittleness and polycrystalline defects. Herein, we present a molecular weaving strategy to construct an interwoven mixed matrix membrane of rigid 3D UiO-66 gel and flexible polyethyleneimine (PEI) polymers, achieving both structural robustness and tunable porosity. Glutaraldehyde crosslinking further stabilizes the hybrid framework, enhancing mechanical durability while refining pore dimensions to 0.35 nm, ideal for H₂/CO₂ sieving. The resultant ultrathin (∼50 nm) but flexible membranes, with UiO-66 content up to 46 wt%, exhibit superior separation performance, achieving a H₂ permeance of 845 GPU and H₂/CO₂ selectivity of 16.8, surpassing the 2008 Robeson upper bound. Additionally, we demonstrated the fabrication of defect-free membranes ∼160 cm², showcasing the scalable potential of this method. This work introduces a promising strategy for designing flexible, high-performance MOF-based separation systems, addressing urgent challenges in energy-efficient gas purification and carbon capture.