Reversible CO2 Capture by Conjugated Ionic Liquids through Dynamic Covalent Carbon–Oxygen Bonds

Graphical Dual-tuning method : Through the introduction of a large π-conjugated structure into the anion, a dual-tuning approach to improve CO 2 capture by anion-functionalized ionic liquids (ILs) results in high capacities of up to 0.96 ; and excellent reversibility. Quantum chemical calculations, spectroscopic investigations, and thermogravimetric analysis indicate that the increased capacity is a result of stronger dynamic covalent bonds. The strong chemisorption of CO 2 is always accompanied by a high absorption enthalpy, and traditional methods to reduce the absorption enthalpy lead to decreased CO 2 capacities. Through the introduction of a large π-conjugated structure into the anion, a dual-tuning approach for the improvement of CO 2 capture by anion-functionalized ionic liquids (ILs) resulted in a high capacity of up to 0.96 mol and excellent reversibility. The increased capacity and improved desorption were supported by quantum chemical calculations, spectroscopic investigations, and thermogravimetric analysis. The increased capacity may be a result of the strengthened dynamic covalent bonds in these π-electron-conjugated structures through anion aggregation upon the uptake of CO 2 , and the improved desorption originates from the charge dispersion of interaction sites through the large π-electron delocalization. These results provide important insights into effective strategies for CO 2 capture.