▎ 摘　　要

The effect of gas adsorption on the change in magnetic properties of platinum doped graphene (Pt-graphene) system was investigated using first-principles density-functional theory (DFT). Four chemisorbed gas molecules (N-2, O-2, NO2, SO2) on Pt-graphene each induced a different type of magnetic properties. For N-2 adsorption, there was no spin polarization. However, for the other cases, magnetic properties were altered by occurring spin polarization. O-2 adsorption led to local polarization on the gas molecule, and two types of complete polarization were introduced on Pt-graphene by NO2 and SO2 adsorption. Also, in the latter two cases, an interesting difference was found in the spin direction of gas and Pt-graphene. NO2 adsorption induced the same spin direction on the adsorbate and substrate, while SO2 adsorption introduced the opposite spin directions. Thus, these differences in magnetic properties of the Pt-graphene according to the type of adsorbed gas molecules are expected to play a vital role in application as gas sensor or spintronic devices. (C) 2013 Elsevier B.V. All rights reserved.