Nitrogen-doped fullerenes for CO 2 capture: a DFT study

The structural and electronic properties of several nitrogen-doped fullerenes, C 60−2 n N 2n ( n = 1–12), have been studied using density functional theory (DFT) at the M06L/6-311+G(d)//M06L/6-31G(d) level. The electronic features studied using a molecular electrostatic potential (MESP) topology analysis revealed that increasing the N-doping leads to a large improvement in the electron density of the carbon cage. As a result, the N-doped fullerenes showed a stronger interaction with CO 2 molecules than C 60 . Also, the formation of large clusters of CO 2 around the N-doped C 60 is modeled which revealed that the interaction energy per CO 2 is better than the interaction of a single CO 2 with the same system. The improved interaction of CO 2 in the cluster is attributed to the positive cooperative interaction arising between the adsorbed CO 2 molecules. The study also examined the MESP features and the CO 2 binding affinity of the anionic modification of the N-doped C 60 by attaching a CN − unit on a carbon center. Compared to the N-doped C 60 , the highly electron-rich anion (C 60−2 n N 2 n CN) − showed improved affinity to CO 2 . The superior electronic features and CO 2 binding energy data of N -fullerenes and N -cyanofullerides suggest that they are potent CO 2 capturing agents.