Energy-Efficient CO ₂ Desorption of Ionic Liquid Solvents Facilitated by Homogeneous Lewis Acid Catalysts

Ionic liquids (ILs) show great potential for carbon dioxide (CO 2 ) capture due to their designable structures and dual roles as absorbents and catalysts. Our previously designed IL solvent ([Cho][Triz]/TMS) showed good absorption performance but a slow regeneration rate. Here, a novel strategy to promote CO 2 desorption in IL absorbents at lower temperatures using homogeneous Lewis acid IL (LAIL) catalysts was proposed. The cobalt (Co)-based LAIL [Bmim] 2 [CoCl 4 ] exhibited superior performance, with the CO 2 desorption amount enhanced by 54.1% and activation energy reduced by 30.3% compared with the blank test, leading to low regeneration energy consumption (0.90 GJ/t CO 2 ), which was ascribed to a simultaneous increase in Brønsted and Lewis acid sites, promoting C–N bond cleavage by C2–H in [Bmim] 2 2+ and Co sites in [CoCl 4 ] 2– . The environmental impact of IL-based CO 2 capture processes, evaluated by the green degree method, demonstrated that the green degree production value of the IL-LAIL system is 79.6 and 673.6 gd/h higher than that of the IL and MEA systems, respectively, indicating greater environmental sustainability. This study provides a viable strategy for employing homogeneous catalysts to facilitate energy-efficient CO 2 capture.