Fe3O4 modified Pt/C electro-catalyst was synthesized and studied. Fe3O4 and Fe3O4 with carbon coating (designated as Fe3O4/C) were prepared by co-precipitation method and ethyl acetate pretreatment. Fe3O4 and Fe3O4/C were sprayed onto the Pt/C cathode surface. X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM) results show that Fe3O4 and Fe3O4 with carbon coating nano-particles (Fe3O4/C) are distributed evenly and c.a. 11.2 nm and 14.3 nm, respectively. TEM images show that electrode surfaces with Fe3O4 and Fe3O4/C are of little difference from that with Pt/C only; Fe3O4/C is much more evenly distributed on the electrode surface than Fe3O4 because of the adaptability of carbon coating. Cathodic curves of Rotating Disk Electrode (RDE) tests shows that the adding of Fe3O4 (7 wt %) improves oxygen reduction reaction (ORR) activity about 30 mV in both cases. The adding of Fe3O4/C (Fe3O4: 7 wt %) to the Pt/C catalysts demonstrates the highest peak current of about 13.8 mA•cm-2 in all cases. The promotion of Fe3O4 in O2 enrichment and dispersion of Pt particles are confirmed in the study. The paramagnetism of Fe3O4 and its promotion in 4-electron oxygen reduction reaction (ORR) are the possible reasons for the promotion.his template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.