▎ 摘　　要

In this paper we have investigated the adsorption of the gas molecules (NO2, NO) on graphene, using first-principles methods. For full geometric relaxation of the molecules in the vicinity of a graphene sheet, we obtain the adsorption geometry, adsorption energies, charge transfer and density of states (DOS). We can identify which of the adsorbate molecules is acting as donor or acceptor. We find that the conductance of graphene at the Fermi level decreases with adsorbing NO2 molecules and increases with adsorbing NO molecules.