A first-principles study of gas adsorption on monolayer AlN sheet

The monolayer AlN is one of graphene-like 2D material. On the basis of density functional theory (DFT) calculations, the adsorption of CO2, CO, H2, N2, CH4, O2 and NO on the monolayer AlN was investigated. Due to the dipole moment of the Al-N bond, the gas molecules can be adsorbed directly on the AlN sheet. This avoids the problem about formation of metal clusters using metal decorated carbon nanostructures as gas storage materials. Among all the gas molecules, only CO2 on the AlN sheet has strong interaction with adsorption energy of 0.91 eV. While other gas molecules bind to the AlN sheet much weakly with the adsorption energy being less than 0.5 eV. Due to the charge transfer between gas molecules and the AlN sheet, the AlN sheet can be used to gas sensors for CO2, CO, H2, O2 and NO. Moreover, the AlN sheet can be taken potential applications as sorbent materials for CO2 separation and capture from gas mixture.