Reversible CO(2) storage and efficient separation using Ca decorated porphyrin-like porous C(24)N(24) fullerene: a DFT study

The search for novel materials for effective storage and separation of CO(2) 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 (C(24)N(24)) as a promising material for CO(2) storage and separation using thorough density functional theory calculations. The results show that CO(2) is physisorbed on bare C(24)N(24), implying that this material cannot be used for efficient CO(2) storage. Coating C(24)N(24) with Ca atoms, on the other hand, can greatly improve the adsorption strength of CO(2) molecules due to polarization and charge-transfer effects. Furthermore, the average adsorption energy for each of the maximum 24 absorbed CO(2) molecules on the fully decorated Ca(6)C(24)N(24) fullerene is −0.40 eV, which fulfills the requirement needed for efficient CO(2) storage (−0.40 to −0.80 eV). The Ca coated C(24)N(24) fullerene also have a strong potential for CO(2) separation from CO(2)/H(2), CO(2)/CH(4), and CO(2)/N(2) mixtures.