Metal-organic cages improving microporosity in polymeric membrane for superior CO 2 capture

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 2 emissions. Here, we synthesized a series of novel metal organic cages (MOCs) with aperture pore size precisely positioned between CO 2 and N 2 or CH 4 . 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 2 permeability of 8803.4 barrer and CO 2 /N 2 selectivity of 59.9, far exceeding the 2019 upper bound. This approach opens opportunities for improving the porous structure of polymeric membranes for CO 2 capture and other separation applications.