Atomic Adsorption on Nitrogenated Holey Graphene

Two-dimensional (2D) crystals with C₂N stoichiometry have recently been synthesized. This novel material, dubbed nitrogenated holey graphene (NHG), is a semiconductor unlike pristine graphene. For any novel material, it is fundamental to understand the behaviors of different adatoms on its surface, a process responsible for a rich phenomenology. In this work, we employed first-principles calculations and a hybrid quantum mechanics/molecular mechanics method to investigate the adsorption of H, B, and O on NHG sheets. The adsorption of H atoms could prove important for applications in hydrogen storage and gas sensors, whereas the adsorption of O in any new material is important to understand its oxidation process. Both N and B are common dopants in carbon-based systems, such as in BNC structures. We found that H and B prefer to adsorb on top of a nitrogen atom, whereas O prefers to adsorb on top of a carbon–carbon bond. The electronic structure of NHG also changes as a result of the presence of adatoms, with the appearance of midgap states close to the Fermi level. In the case of NHG + H and NHG + B, we observed the appearance of a finite magnetic moment, related to the midgap states, which could give rise to a magnetoresistance effect. Our results provide insight into the adsorption of impurities on this novel 2D carbon-based material, with potential for applications in novel electronic devices.