A Rational Design of Microporous Aerogel for Excellent CO2 Capture and Selectivities via Co-Synergistic Effects of Electrostatic In-plane and π-π Stacking Interactions1, 2

Microporous aerogel (PEINK) with a nitrogen-containing framework, high CO2 capture and selectivity were obtained through the condensation polymerization of 1,3,5-tris-(4-fluorobenzoyl)benzene with 5-hydroxyindol. The uptake capacity for CO2 reached up to 17.7 wt % (1.0 bar, 273 K), and the high CO2/N-2 = 16, CO2/CH4 = 29 selectivity. Density functional theory illustrated that a CO2 molecular was captured via synergistic efforts with pi-pi stacking of indole group and electrostatic in-plane binding of an adjacent ether unit, thus the selectivity and adsorption of CO2 were strengthen. The proposed co-synergistic effect on one CO2 molecular is expected to be a new theory for the design of high CO2 capture materials.