Functional liquid absorbents for CO₂ capture and catalytic conversion: from organic amines to porous liquids

The continuous rise in CO₂ emissions has led to severe global climate challenges, making the capture and conversion of CO₂ a critical pathway toward carbon neutrality and sustainable development. This review systematically summarizes recent advances in CO₂ capture and catalytic conversion using four representative media, including organic amine solutions, ionic liquids (ILs), deep eutectic solvents (DESs), and porous liquids (PLs). Organic amine solutions, as the most mature CO₂ absorption technology, are still limited by high regeneration energy consumption and severe equipment corrosion. ILs can not only achieve efficient and selective capture but also enable catalytic activation of CO₂. DESs offer the advantages of simple preparation and low cost while retaining the benefits of ILs to synergistically activate CO₂ and substrates through ionic sites and hydrogen-bonding networks. PLs, as an emerging class of functional liquid materials, combine permanent porosity with macroscopic fluidity. They enable a synergistic adsorption-absorption effect and provide unique catalytic microenvironments for CO₂ conversion. This review systematically elucidates the capture mechanisms, activation pathways, and conversion characteristics of four media, and compares their respective advantages and application limitations. The aim is to provide theoretical guidance for the design and optimization of high-performance absorbents and catalysts, and to promote the development of low-energy, high-efficiency integrated CO₂ capture and conversion technologies.