One-step synthesis of hydroxyl-functionalized ionic hyper-cross-linked polymers with high surface areas for efficient...

Ionic liquid-based functional materials have attracted significant attention for their distinctive structure in the field of CO₂ capture and conversion. In this work, a series of hydroxyl-functionalized ionic hyper-cross-linked polymers are prepared through a one-step Friedel-Crafts reaction involving hypoxanthine (HX) and benzimidazole (BI) as the monomers, along with various halohydrocarbon crosslinking agents. These polymers demonstrate a high specific surface area (558-1480 m²·g^-1), well-developed microporous structure, and unique ion sites, enabling them to exhibit remarkable and reversible CO₂ adsorption properties. Particularly noteworthy is their CO₂ adsorption capacity, which surpasses that of similar ionic polymers documented in the literature, reaching 157.5 mg·g^-1 at 273 K and 1 bar. Additionally, these polymers function as recyclable catalysts in the cycloaddition reaction of CO₂ and epoxides, enabling the conversion of CO₂ into cyclic carbonates with yields of up to 99 % even without a co-catalyst. Mechanism investigation reveals that the introduction of hydroxyl groups in the polymer is the key to improving catalytic activity through a synergistic catalytic effect. This research provides a novel concept for designing ionic functional materials with capabilities in both CO₂ adsorption and catalytic activity.