Efficient CO₂ Capture under Humid Conditions on a Novel Amide-Functionalized Fe-soc Metal-Organic Framework

CO₂ is the main source of the greenhouse gases, and its capture from flue gas under humid conditions is challenging but important for promoting carbon neutrality. Herein, we report a novel soc topology Fe-based metal-organic framework (Fe-dbai) with highly efficient postcombusion CO₂ capture performance by integrating multiple specific functionalities, such as unsaturated metal sites and amide functional groups. The CO₂ adsorption capacity and CO₂/N₂ selectivity of Fe-dbai are high up to 6.4 mmol/g and 64 (298 K, 1 bar), respectively, superior to many other reported MOFs. More importantly, the CO₂ working capacity of Fe-dbai under 60% RH conditions preserves 94% of that under dry conditions in the breakthrough experiments of CO₂/N₂ (15:85, v/v) mixtures. The molecular simulation highlights that the electronegative amide CO- group has a good affinity for CO₂ and can improve the interaction between Fe UMS and CO₂. Although H₂O molecules will occupy a small fraction of the adsorption sites, the confinement effect it produces can enhance the adsorption affinity of the framework for CO₂, which results in Fe-dbai retaining most of the CO₂ adsorption capacity under humid conditions. The excellent CO₂ capture performance makes Fe-dbai a potential candidate for the practical application of CO₂ capture.