Synergistic Hydrophobic-Polar Microenvironments in Corrugated Channels Enable Exceptional Moisture-Tolerant CO₂...

Overcoming the moisture sensitivity of porous adsorbents remains a critical challenge for industrial carbon capture, hindered by the inherent trade-off between strong CO₂ affinity and competitive water adsorption. Here, we report a series of isostructural porous coordination polymers (PCP-H, PCP-NH₂, and PCP-OH) that realize corrugated channels where confined hydrophobic parallel aromatic walls and tunable isolated polar sites cooperate to form clip-like traps for moisture-tolerant CO₂ capture. PCP-NH₂ is presented as the demonstration that achieves an exceptional CO₂/N₂ selectivity, significantly outperforming its non-functionalized and hydroxylated analogues despite identical framework topologies. Critically, PCP-NH₂ integrates excellent CO₂ breakthrough performance with exceptional moisture tolerance (retained 95% capacity at 70%RH, even with trace SO₂ present) and stable performance over 99 cycles with fast kinetics under simulated flue gas conditions. In situ single-crystal x-ray diffraction and diffuse reflectance infrared Fourier transform spectroscopy, together with grand canonical Monte Carlo simulations, reveal that CO₂ molecules are stabilized through cooperative C═O···H and π···π interactions within the clip-like traps, while hydrophobic channel surfaces and spatially separated polar sites suppress H₂O uptake and preserve CO₂ selectivity at high humidity. These findings reveal a general design principle whereby synergistic hydrophobic-polar microenvironments reconcile strong target binding with hydrolytic robustness for challenging gas separations.