UV cross-linked CO2–philic MOF–polymer composite membranes with excellent interfacial properties and separation performance are achieved via MOF surface chemistry modification.

Mixed matrix membranes (MMMs) are one of the most promising solutions for energy-efficient gas separation. However, conventional MMM synthesis methods inevitably lead to poor filler–polymer interfacial compatibility, filler agglomeration, and limited loading. Herein, inspired by symbiotic relationships in nature, we designed a universal bottom-up method for in situ nanosized metal organic framework (MOF) assembly within polymer matrices. Consequently, our method eliminating the traditional postsynthetic step significantly enhanced MOF dispersion, interfacial compatibility, and loading to an unprecedented 67.2 wt % in synthesized MMMs. Utilizing experimental techniques and complementary density functional theory (DFT) simulation, we validated that these enhancements synergistically ameliorated CO2 solubility, which was significantly different from other works where MOF typically promoted gas diffusion. Our approach simultaneously improves CO2 permeability and selectivity, and superior carbon capture performance is maintained even during long-term tests; the mechanical strength is retained even with ultrahigh MOF loadings. This symbiosis-inspired de novo strategy can potentially pave the way for next-generation MMMs that can fully exploit the unique characteristics of both MOFs and matrices.

Branched plant root mimicking PEO chains can simultaneously increase the gas separation performance, membrane stability and mechanical strength of CO2-philic membranes for superior carbon capture.

The high fractional free volume (FFV) endowed polymers of intrinsic microporosity (PIMs) with high gas permeability but low selectivity. Herein, an intermediate temperature range was deliberately utilized to tune PIM‐1 membrane microstructure in nitrogen atmosphere to enhance gas separation performance. During intermediate thermal manipulation, the synergistic effects of thermal‐induced cross‐linking and decomposition on PIM‐1 membranes have optimized the micropores for significantly increasing membrane molecular‐sieving ability with the boosted selectivity of 350 (H2/N2), 1,472 (H2/CH4), 3,774 (H2/C3H8), and 197 (CO2/CH4) respectively, with the H2 permeability of 234 Barrer, correspondingly, surpassing the “Robeson's Upper Bound”. The facile strategy simultaneously utilizing the thermal‐induced cross‐linking and decomposition, might provide a new platform to develop the high‐performance membranes for highly‐efficient hydrogen purification and CO2 separations.

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Enhancing the monodispersity and surface properties of nanoporous zeolitic imidazolate frameworks (ZIFs) are crucial for maximizing their performance in advanced nanocomposites for separations. Herein, we developed an in situ method to synthesize monodispersed ZIF-8 nanocrystals with unique dopamine (DA) surface decoration layer (ZIF-8-DA) in an aqueous solution at room temperature. Interestingly, the in situ formation of the monodispersed ZIF-8-DA nanocrystals experiences a triple-stage crystallization process, resulting in a rhombic dodecahedron architecture, which is greatly different from the synthesis of conventional ZIF-8. The crystallinity and abundant microporosity of ZIF-8-DA nanocrystals is well maintained even with the DA surface decoration. Owing to the advanced surface compatibility and pore properties of ZIF-8-DA, ZIF-8-DA/Matrimid mixed-matrix membranes exhibit both higher gas permeability and selectivity than the pristine Matrimid polyimide membrane, which breaks out the traditional “trade-off” phenomena between permeability and selectivity.

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The separation mechanism and material design of advanced PEO membranes for CO2 capture have been reviewed in detail and further directions in this field have been provided.