Hollow Nitrogen-Doped Carbon Spheres with Fe3O4 Nanoparticles Encapsulated as a Highly Active Oxygen-Reduction Catalyst

The development of nonprecious electrocatalyst with low cost and high efficiency for the oxygen reduction reaction (ORR) is a main challenge for electro-chemical energy technology. In this work, a hierarchical hollow core shell structured N-doped carbon spheres (N-HSCS), in which Fe3O4 nanoparticles are encapsulated (Fe3O4/N-HCSC) has been successfully prepared. The Fe3O4/N-HCSC electrocatalyst exhibits a remarkable catalytic performance toward ORR The porous hollow core shell structure and synergistic effect between Fe3O4 and protective nitrogen doped graphitic layers are mainly responsible for such an excellent ORR catalytic property and stability. This work demonstrates a promising strategy of nanostructure-engineering to the future design and preparation of highly efficient non-noble metal electrocatalysts.