▎ 摘　　要

Density functional theory calculations were performed to cast insight into the mechanism of the activation of O-2 by Pt single atom and Pt-4 nanocluster deposited on single vacancy and different pyridinic N doped graphene. It is found that the graphene by introducing pyridinic N can make supported Pt single atom and Pt-4 nanocluster accumulate more positive polarized charges, which upshift the d-band centers of the supported Pt single atom and Pt-4 nanocluster toward the Fermi level. It is also observed that the more pyridinic N in grapheme is, the more positive polarized charges is accumulated by supported Pt single atom and Pt-4 nanocluster. The positive charged sites is favour the dissociation of O-2. We find that the energy barrier of O-2 dissociation almost decrease linearly with the increase Pt positive polarized charges. Our work reveals that the Pt positive polarized charges can act as microscopic driving force for O-2 dissociation. (C)2017 Elsevier Ltd. All rights reserved.