Absorption of nitrogen oxides by ionic liquids: a mini review

Nitrous oxide (N 2 O) is a potent greenhouse gas, whereas nitrogen oxides (NOx) are major atmospheric pollutants. Owing to their significant environmental impacts, ionic liquids (ILs) have attracted considerable attention as highly tunable absorbents for nitrogen oxide capture and separation. This mini‐review summarizes recent advances in the absorption of N 2 O, nitric oxide (NO), and nitrogen dioxide (NO 2 ) by ILs, with emphasis on absorption performance, molecular interaction mechanisms, and structure–property relationships. Mechanistically, N 2 O absorption is primarily governed by anion–N 2 O electrostatic interactions, whereas weakened cation–anion interactions enhance N 2 O solubility. In contrast, NO capture relies predominantly on chemical absorption, while NO 2 exhibits significantly higher physical solubility than NO, suggesting that catalytic oxidation of NO prior to absorption represents a potential strategy. Recent advances in amino‐functionalized ILs and transition metal‐assisted systems have substantially improved NO capture through chemical interactions. Current challenges and future perspectives are also highlighted to facilitate the rational design of task‐specific IL‐based absorbents for industrial gas purification.