Strong chemical adsorption of CO2 and N2 on a five-vacancy graphene surface

Carbon dioxide adsorption on a five-vacancy graphene surface was mainly studied using density functional theory. Molecular nitrogen was also studied in order to analyze the selectivity for CO2 of this surface with respect to N-2. Strong chemical adsorption energies were observed for CO2 (-6.09 eV) and N-2 (-4.34 eV). A planar heterocyclic system together with a metal-semimetal (an apparent gap of 0.17 eV) electronic transition was obtained after CO2 adsorption. No electronic transition was observed after N-2 adsorption. Electronic charge transfer from the five-vacancy graphene surface to CO2 and N-2 is consequence of the leftward shift of the Fermi energy of the five-vacancy graphene surface with respect to the Dirac point indicating p-doping charge transfer mechanism. On the other hand, a decrease in the magnetic moment was observed as a consequence of the adsorption of both molecules. The former findings could be used to create surfaces with strong and more sensitive CO2 adsorption and CO2 electronic sensors.