CO and NO selective adsorption by a C16Mg8O8 nanocage: A DFT Study

Abstract

Density functional theory (DFT) calculations were performed to stabilize a representative C16Mg8O8 nanocage derived from C32 and Mg16O16 counterparts for selective adsorption of carbon monoxide (CO) and nitrogen monoxide (NO) gaseous molecules. After obtaining optimized structures, molecular features were evaluated for describing the model systems. Diagrams of density of states (DOS) revealed that the energy differences between frontier molecular orbital levels of the highest occupied and the lowest unoccupied molecular orbitals (HOMO and LUMO) of the stabilized C16Mg8O8 nanocage could provide a more proper semiconductor in comparison with each of the original C32 and Mg16O16 cages. To explore the advantage of such C16Mg8O8 nanocage for CO and NO gases adsorption, molecular descriptors such as energies, geometries, and electronic structures were characterized for all possible adsorption configurations of bimolecular formation of gas . . . nanocage. Significant changes of HOMO and LUMO levels besides the values of corresponding energy gaps of C16Mg8O8 nanocage in singular and bimolecular systems could help to recognize adsorption of each of CO and NO gaseous molecules. Furthermore, more variations of energy gaps in the process of gas . . . nanocage bimolecular formation could lead to more sensitivity of nanocage for detection of adsorbed gases. As a consequence, the investigated C16Mg8O8 nanocage was introduced for differential recognition of CO and NO gases regarding several environmental health issues.