Research Progress of Ionic Liquids Hybridized with Porous Materials for CO2 Capture: From Bulk to Confinement-Enhanced Adsorbents

The continuous rise in carbon emissions poses a serious threat to the global climate, driving the urgent need for efficient CCUS technologies. Ionic liquids (ILs), with their negligible vapor pressure, excellent thermal stability, and tunable molecular structures, have emerged as promising materials for CO2 capture. However, the high viscosity of bulk ILs severely restricts gas mass transfer. To overcome this limitation, integrating ILs with porous materials featuring large surface areas and well-defined pore structures has emerged as a synergistic strategy, combining the high CO2 affinity and selectivity of ILs with the rapid mass transfer and structural stability of porous supports. This review systematically summarizes the CO2 capture mechanisms and limitations of bulk ILs and further highlights recent advances in the design, synthesis, and applications of IL-based hybrid adsorbents. Particular attention is given to confinement-enhanced mechanisms, whereby nanoscale confinement fundamentally alters the physicochemical behavior of ILs, transforming them from disordered bulk liquids into ordered, interface-dominated systems. In addition, the life-cycle assessment and techno-economic analysis of IL hybrid systems are critically evaluated.