Integration of MOF UiO-66 into Zinc Coordination Polymer Glass Membranes for Enhanced Gas Separation

Membrane-based gas separation technologies have attracted significant attention for their energy efficiency and environmental benefits. As a type of promising candidate material, MOF glass has shown great potential in the gas separation membrane by improving interfacial compatibility with other functional components and processability toward continuous, pinhole-free films. In this study, we report the development of self-supporting MOF crystal-glass composite membranes by integrating UiO-66 crystals into a melt-processable zinc coordination polymer glass (a g ZnCP_bim, where a g represents amorphization by glass formation) matrix. The ZnCP_bim exhibited a low melting temperature and a high glass-forming ability, allowing for in situ melt-quenching to form defect-minimized MOF crystal-glass composite membranes. UiO-66/a g ZnCP_bim composite membranes with varying UiO-66 loadings (up to 50 wt %) were fabricated to investigate the effect of the filler content on membrane properties. Structural characterizations confirmed the preservation of the UiO-66 crystallinity and the amorphous nature of the ZnCP_bim glass matrix. In situ THz-FarIR spectroscopy revealed strong interfacial interactions and irreversible structural transitions during thermal processing. Gas adsorption–desorption of CO 2 and N 2 showed the increased porosity introduced by UiO-66 and enhanced affinity for CO 2 molecules. Gas permeation measurements of self-supporting UiO-66/a g ZnCP_bim membranes for N 2 /CH 4 and H 2 /CO 2 showed a notable improvement in both permeability and selectivity, which exceeded the Robeson upper bound.