The strategies for improving carbon dioxide chemisorption by functionalized ionic liquids

CO₂ capture and storage (CCS) has attracted worldwide interest because CO₂ makes a significant contribution to global warming and climate change as a major greenhouse gas. Ionic liquids are promising absorbents for carbon capture due to their negligible vapour pressures, wide liquid range, high thermal stabilities and tunable properties. This perspective review focuses on the recent advances in chemical absorption of CO₂ using functionalized ionic liquids, including amino acid-based ionic liquids, azole-based ionic liquids, phenol-based ionic liquids, and so on. Strategies for how to enhance CO₂ absorption capacity, reduce CO₂ absorption enthalpy, and improve CO₂ absorption kinetics are presented. The absorption mechanisms of these functionalized ionic liquids are explained at the molecular level through a combination of theoretical calculation and spectroscopic investigation. Particular attention is paid to the latest developments in carbon capture by non-amino anion-functionalized ionic liquids. In the last section, future directions and prospects for CO₂ capture by functionalized ionic liquids are outlined.