In this paper, we presented a hybrid composite of graphene quantum dots (GQDs)-modified three-dimensional graphene nanoribbons (3D GNRs) composite linked by Fe3O4 and CoO nanoparticles through reflux and ultrasonic treatment with GQDs, denoted as 3D GQDs-Fe3O4/CoO@GNRs (3D GFCG). In this hybrid, the 3D GNRs framework strengthened the electrical conductivity and the synergistic effects between GQDs and 3D GFCG enhanced the oxygen reduction reaction (ORR) activity of the nanocomposite. The results imply that decorating GQDs with other electro-catalysts is an effective strategy to synergistically improve their ORR activity.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Synthesis of GNRs
        2.2 Synthesis of GQDs
        2.3 Synthesis of 3D GQDs-Fe3O4CoO@GNRs
        2.4 Electrochemical measurement
        2.5 Sample characterization
    3 Results and Discussion
    4 Conclusion
    Acknowledgements 
    References

• Xiyu Zhao(School of Chemistry and Chemical Engineering, Key Laboratory of Hexi Corridor Resources Utilization of Gansu, Hexi University)
• Changrui Lu(School of Chemistry and Chemical Engineering, Key Laboratory of Hexi Corridor Resources Utilization of Gansu, Hexi University)
• Jing Li(School of Chemistry and Chemical Engineering, Key Laboratory of Hexi Corridor Resources Utilization of Gansu, Hexi University)
• Caiyun Liu(School of Chemistry and Chemical Engineering, Key Laboratory of Hexi Corridor Resources Utilization of Gansu, Hexi University)
• Cheng Cao(School of Chemistry and Chemical Engineering, Key Laboratory of Hexi Corridor Resources Utilization of Gansu, Hexi University)
• Tianli Wu(Henan Key Laboratory of Photovoltaic Materials, Henan University)