Metal-organic cages improving microporosity in polymeric membrane for superior CO<sub>2</sub> capture.

Guan, Jian; Du, Jingcheng; Sun, Qian; He, Wen; Ma, Ji; Hassan, Shabi Ui; Wu, Ji; Zhang, Hongjun et al. · Sci Adv · 2025

basic_science · Level V

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Abstract

Mixed matrix membranes, with well-designed pore structure inside the polymeric matrix via the incorporation of inorganic components, offer a promising solution for addressing CO<sub>2</sub> emissions. Here, we synthesized a series of novel metal organic cages (MOCs) with aperture pore size precisely positioned between CO<sub>2</sub> and N<sub>2</sub> or CH<sub>4</sub>. These MOCs were uniformly dispersed in the polymers of intrinsic microporosity (PIM-1). Among them, the MOC-Ph cage effectively modulated chain packing and optimized the microporous structure of the membrane. Remarkably, the PIM-Ph-5% membrane shows superior performance, achieving an excellent CO<sub>2</sub> permeability of 8803.4 barrer and CO<sub>2</sub>/N<sub>2</sub> selectivity of 59.9, far exceeding the 2019 upper bound. This approach opens opportunities for improving the porous structure of polymeric membranes for CO<sub>2</sub> capture and other separation applications.