Carbon dioxide capture by planar (AlN)n clusters (n=3-5).

Searching for materials and technologies of efficient CO2 capture is of the utmost importance to reduce the CO2 impact on the environment. Therefore, the (AlN)n clusters (n = 3-5) are researched using density functional theoretical calculations. The results of the optimization show that the most stable structures of (AlN)n clusters all display planar configurations at B3LYP and G3B3 methods, which are consistent with the reported results. For these planar clusters, we further systematically studied their interactions with carbon dioxide molecules to understand their adsorption behavior at the B3LYP/6-311+G(d,p) level, including geometric optimization, binding energy, bond index, and electrostatic. We found that the planar structures of (AlN)n (n = 3-5) can capture 3-5 CO2 molecules. The result indicates that (AlN)n (n = 3-5) clusters binding with CO2 is an exothermic process (the capture of every CO2 molecule on (AlN)n clusters releases at least 30 kcal mol-1 in relative free energy values). These analysis results are expected to further motivate the applications of clusters to be efficient CO2 capture materials.