▎ 摘　　要

The construction and surface modification of three-dimensional (3D) graphene structures have been recognized as effective ways to prepare high-performance graphene-based composites in energy-related applications. Herein, on the basis of well-defined morphology and efficient electron conduction, the 3D highly-stable graphene hollow nanospheres have been synthesized by using sacrificial template method. The asprepared 3D graphene nanospheres exhibit superior mechanical stability, electrochemical stability, and strong hydrophobicity, which may accelerate the emission of H2O in acidic medium-based ORR. Accordingly, the 3D highly-stable graphene nanospheres are used to confine tiny Pt nanoparticles (3D r-GO@Pt HNSs) for ORR in acidic medium, exhibiting superior activity with 4-electron-transfered pathway. Meanwhile, dramatically improved durability are achieved in terms of both ORR mass activity and electrochemically surface area compared to those of commercial Pt/C. (C) 2019, Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V.