Reversible CO storage and efficient separation using Ca decorated porphyrin-like porous CN fullerene: a DFT study.

The search for novel materials for effective storage and separation of CO molecules is a critical issue for eliminating or lowering this harmful greenhouse gas. In this paper, we investigate the potential application of a porphyrin-like porous fullerene (CN) as a promising material for CO storage and separation using thorough density functional theory calculations. The results show that CO is physisorbed on bare CN, implying that this material cannot be used for efficient CO storage. Coating CN with Ca atoms, on the other hand, can greatly improve the adsorption strength of CO molecules due to polarization and charge-transfer effects. Furthermore, the average adsorption energy for each of the maximum 24 absorbed CO molecules on the fully decorated CaCN fullerene is -0.40 eV, which fulfills the requirement needed for efficient CO storage (-0.40 to -0.80 eV). The Ca coated CN fullerene also have a strong potential for CO separation from CO/H, CO/CH, and CO/N mixtures.