The influence of adsorbates on the electronic and magnetic properties of graphene possessing the H-vacancy defects was investigated using the quantum-chemistry methods. It was found that the H vacancies in graphene significantly improve its chemical reactivity to environment due to the unpaired electron left on the vacancy. Therefore, depending on the type of molecule adsorbed, the interaction between the adsorbate and the vacancy could occur with or without the formation of the bond. In case of the bond formation the unpaired electron supplied by the vacancy was removed and the electronic and magnetic properties of graphene became similar to that of pure defect-free graphene. Moreover, adsorption led to degradation or vanishing of magnetism induced by the H vacancies in graphene, except in the case when the CO2 molecule was attached, which was found to generate localized state with the unpaired electron after bonding with the H vacancy. Stability of ferromagnetism induced by the CO2 molecules bound to the vacancies was found to be low. There were two reasons for low stability: localization of the spin density of the localized state entirely on adsorbate that minimize the interference of the spin tails of these states and the possibility of pairing of two neighbouring CO2 molecules to C2O4.

Influence of Adsorbates on the Electronic and Magnetic Properties of Graphene with H-Vacancy Defects. J.Berashevich, T.Chakraborty: Physical Review B, 2010, 82[13], 134415