We investigated the structural and electronic properties of Pt13 nanoparticles on various nitrogen(N)-doped graphene and their interaction with O by density functional theory(DFT)calculations.The results revealed that the N-doping can greatly enhance the binding strength of Pt13 nanoparticles on the graphene surface,thus ensuring their high stability.For NC doping(N atoms directly substituting for C atoms),the enhanced binding strength of the Pt13 cluster is attributed to the activation of the carbon atoms around the N-dopant,while the strong hybridization of the d states of the Pt13 cluster with the sp2 dangling bonds of the N atoms in defective N-doped graphenes contributes to the strong adsorption.Moreover,a certain amount of electrons are transferred from Pt13 to the substrate accompanied by a substantial downshift of the Pt13 d-band center,thus greatly weakening the interaction of O on these composites: the adsorption energy of O is reduced from-3.700 eV on freestanding Pt13 nanoparticles to-1.762,-1.723,and-1.507 eV on deposited Pt13 ones on NC,3NV,and 4ND structures,respectively.Hence,it is expected that N-doped graphene supported Pt nanoparticles exhibit super catalytic reactivity in the ORR.