Acid-base dual-functional cooperation and molecular sieving in hypercrosslinked porous polymers for CO2 capture

Efficient CO₂ capture and separation are essential to enhance natural gas utilization and reduce coal-fired flue gas emissions, mitigating the climate change. Here, we introduce a novel acid-base dual-functional synergistic adsorption strategy by synthesizing a hypercrosslinked porous polymer (HCP-A-S) containing both amino and sulfonic acid functionalities. The material exhibits 0.34-nm ultramicropores and cooperative –NH₂/–SO₃H groups that preferentially adsorb CO₂, with CO₂ uptake and CO₂/N₂ selectivity doubling that of the corresponding single-site HCP. DFT calculations reveal that the negatively charged amino groups and sulfonic acid moieties synergistically enhance CO₂ affinity through strong electrostatic and dipole–quadrupole interactions, facilitating highly selective capture. Dynamic breakthrough experiments confirm HCP-A-S's superior CO₂/N₂ separation performance, high working capacity, and excellent recyclability. This dual-polar-site approach overcomes limitations of traditional single-site adsorbents and offers a cost-effective, scalable pathway to high-performance carbon capture materials.