Engineering Cooperative Pore Microenvironments for Alleviating the Capacity‐Selectivity Trade‐Off in Olefin Separation

ABSTRACT Engineering cooperative pore microenvironments offers an attractive strategy for overcoming the long‐standing trade‐off between adsorption capacity and selectivity in molecular separations. However, most porous adsorbents rely on isolated adsorption sites, limiting their ability to simultaneously achieve strong adsorption and precise molecular recognition. Here, we establish a cooperative pore microenvironment engineering strategy by integrating open Fe sites with a multifunctional π‐rich organic linker into a robust Fe‐MOF , creating spatially cooperative adsorption domains for propylene recognition. The synergistic interplay between π‐complexation at the open Fe sites and complementary hydrogen‐bonding interactions within the confined pore environment substantially strengthens host‐guest interactions while preserving high adsorption capacity. Consequently, the material exhibits a high C 3 H 6 uptake of 106.7 cm 3 g −1 at 298 K, an exceptional isosteric heat of adsorption of 67.25 kJ mol −1 , and a remarkable C 3 H 6 /C 2 H 4 selectivity of 18.3 for equimolar mixtures. Dynamic breakthrough experiments further demonstrate efficient polymer‐grade C 2 H 4 purification under humid and elevated‐pressure conditions together with excellent recyclability and scalability. This work establishes cooperative pore microenvironment engineering as a promising strategy for alleviating the capacity‐selectivity trade‐off and achieving a favorable balance among adsorption capacity, molecular recognition, and practical separation performance.