An study of the selective adsorption and separation of CO from a flue gas mixture (CH, CO, N) by ZnLi clusters.

Due to the increasing concentration of CO in the atmosphere and its negative effect on the environment, selective adsorption of CO from flue gas has become significantly important. In this study, we have considered a Zn-doped lithium cluster, ZnLi cluster, featuring a planar pentacoordinate Zn centre, as a potential candidate for selective CO capture and separation from a flue gas mixture (CH, CO, N). The binding energy calculation and non-covalent interaction study showed that CO molecules bind relatively strongly as compared to N and CH molecules. The metal cluster can bind five CO, five CH, and four N molecules with average binding energies of -9.2, -4.4, and -6.1 kcal mol, respectively. Decomposition of the binding energy through symmetry-adapted perturbation theory analysis reveals that the electrostatic component plays a major role. The cationic cluster may be a promising candidate for selective CO capture and can be used as a pollution-controlling agent. The calculated adsorption energy of HS is quite closer to that of CO, suggesting competitive adsorption between CO and HS. The adsorption energies of HO and NH are higher compared to CO, indicating that these gases may be a potential threat to CO capture.