▎ 摘　　要

Novel NiFe2O4/N-Gr nanohybrid with the nitrogen doped graphene (N-Gr) loading from 40%, 50%, 65%, and 80% were successfully prepared for oxygen reduction reaction (ORR) in fuel cells (FCs) by a simple, scalable hydrothermal method. The obtained X-Ray Powder Diffraction (XRD) images confirm the pure Face Centered Cubic (FCC) single phase of NiFe2O4/N-Gr nanohybrid. The average crystallite size remains within the range 20 +/- 2 nm. Scanning Electron Microscopy (SEM) results showed aggregation of ferrite nanoparticles on N-Gr. X-ray photoelectron spectroscopy (XPS) was used to investigate the surface chemical composition and cation oxidation states of pure NiFe2O4, N-Gr, and the NiFe2O4/N-Gr nanohybrid. The as-prepared NiFe2O4/N-Gr nanohybrid shows better ORR catalytic activity than pure NiFe2O4 and nitrogen doped graphene (N-Gr), which mainly favours a desirable direct 4e(-) reaction pathway during the ORR process. The admirable electrocatalytic activity of the NiFe2O4/N-Gr nanohybrid is attributed to the strong coupling between the NiFe2O4 nanoparticles and the nitrogen doped graphene as well as the network structure.