Fluorinated tetraphenyladamantane-based microporous organic polymers for efficient CO2 and organic vapors capture

Abstract

The development of advanced microporous organic polymers with high CO₂ capture efficiency and efficient removal of toxic volatile organic compounds under high-humidity conditions remains a significant challenge. In this work, three highly hydrophobic fluorinated tetraphenyladamantyl microporous organic polymers (FMOPs) were fabricated via C–H arylation of 1,3,5,7-tetra(4-bromophenyl)adamantane with 1,2,4,5-tetrafluorobenzene, 1,2,4,6-tetrafluorobenzene, and 1,3,5-trifluorobenzene, respectively. The effects of fluoroaromatic linking units on the porosity, chemical properties, static and dynamic gas/vapor adsorption performance under dry and high humidity conditions were systematically investigated. It was found that fluoroaromatic linkers with isomerism and higher functionality facilitate the formation of highly porous network. The fluorinated FMOPs demonstrated strong hydrophobicity with minimal water vapor adsorption (0.06–0.17 wt%, 298 K/0.9 P/P₀). Among them, FMOP-3 exhibited the highest BET surface areas of 1373 m²/g and a narrow pore size distribution (0.55 nm and 0.93 nm). FMOP-3 also showed remarkable CO₂ uptake (12.2 wt%, 273 K/1.0 bar) and CO₂/N₂ selectivity (46.4). Notably, the FMOPs simultaneously possess exceptional adsorption capacities for benzene (122.5–149.6 wt%) and cyclohexane (95.3–122.8 wt%), significantly surpassing most previously reported porous organic polymers. Moreover, dynamic breakthrough experiments under high humidity (85 % RH) confirmed the high capture efficiency of FMOPs. Experimental characterizations and theoretical calculations confirmed that fluorination enhances the interactions of CO₂@FMOPs and benzene@FMOPs through dipole–quadrupole interactions and fluorine-induced strengthened π-π interactions. These findings highlight the potential of FMOPs for highly efficient CO₂ capture and toxic volatile organic vapor removal under high-humidity conditions. In addition, this work also provides some insights into developing advanced functional adsorbents for gas molecule capture under high-humidity conditions.