Dual-Tuning Azole-Based Ionic Liquids for Reversible CO₂ Capture from Ambient Air

A strategy of tuning azole-based ionic liquids for reversible CO₂ capture from ambient air was reported. Through tuning the basicity of anion as well as the type of cation, an ideal azole-based ionic liquid with both high CO₂ capacity and excellent stability was synthesized, which exhibited a highest single-component isotherm uptake of 2.17 mmol/g at the atmospheric CO₂ concentration of 0.4 mbar at 30 °C, even in the presence of water. The bound CO₂ can be released by relatively mild heating of the IL-CO₂ at 80 °C, which makes it promising for energy-efficient CO₂ desorption and sorbent regeneration, leading to excellent reversibility. To the best of our knowledge, these azole-based ionic liquids are superior to other adsorbent materials for direct air capture due to their dual-tunable properties and high CO₂ capture efficiency, offering a new prospect for efficient and reversible direct air capture technologies.