CO₂ Capture and Separation from N₂/CH₄ Mixtures by Co@B₈/Co@B₈^– and M@B₉/M@B₉^– (M = Ir, Rh, Ru) Clusters: A Theoretical Study

The discovery of advanced materials with high selectivity and efficiency is essential to realize practical carbon capture and sequestration. Here, we have investigated the interactions of the Co@B₈/Co@B₈^– and M@B₉/M@B₉^– (M = Ir, Rh, Ru) clusters with CO₂, N₂, and CH₄ gas molecules theoretically. We found that neutral boron clusters have weak interaction with CO₂, N₂, and CH₄ molecules. Similarly, the clusters with their negative charge states have also weak interaction with N₂ and CH₄ molecules. However, anionic clusters have a strong interaction with CO₂, which can be explained by the Lewis acid–base interaction as CO₂ (Lewis acid) can gain electron easily from the electron-rich anionic clusters. Moreover, the kinetic stability of the formed complexes after CO₂ capture has been validated by ab initio molecular dynamics. In all, the present study demonstrates, for the first time, that the anionic boron wheel ring clusters can be used as potential advanced materials for CO₂ capture and separation from flue gas and natural gas mixtures.