As a novel electrocatalyst for oxygen reduction reaction (ORR), nitrogen-doped graphene aerogel supported cobalt nanoparticles (Co-NGA) is archived by a hybrid-assembly of graphene oxide (GO), o-phthalonitrile and cobalt acetate and the following thermal treatment. The hybrid-assembly process successfully combines the ionic assembly of GO sheets and Co ions with the coordination between o-phthalonitrile and Co ions, which can be converted to nitrogen doped carbon and Co nanoparticles in the pyrolysis process under nitrogen flow. Remarkable features of Co-NGA including the macroporous graphene scaffolds, high surface area, and N/Co-doping effect can lead to a high catalytic efficiency for ORR. As the results, the composites pyrolyzed at 600 degrees C (Co-NGA(600)) shows excellent electrocatalytic activities and kinetics for ORR in basic media, which are comparable with those of Pt/C catalyst, together with superior durability. (C) 2015 Elsevier Inc. All rights reserved.