Synergistic Effects of Fe3O4/N‐Doped Porous Carbon Nanospheres for Enhanced Oxygen Reduction Reaction

Designing transition metal oxide (TMO)/porous carbon composite materials for the oxygen reduction reaction (ORR) is a promising strategy in high‐performance fuel cell technology. In this study, we used the isolation effect and pore‐creating properties of Zn2+ to fabricate a composite material comprising ultrasmall Fe3O4 particles anchored on hierarchically N‐doped porous carbon nanospheres. This material, referred to as CPZ1.0‐Fe0.1, serves as an efficient ORR electrocatalyst in alkaline fuel cells. CPZ1.0‐Fe0.1 exhibits outstanding ORR catalytic activity with a half‐wave potential of 0.86 V in a 0.1 M KOH solution, surpassing that of the Pt/C catalyst (0.82 V). Furthermore, CPZ1.0‐Fe0.1 exhibited excellent stability with minimal current degradation after 18 h of continuous testing. The superior ORR catalytic performance can be attributed to the synergistic effect between the catalytic sites and the high conductivity of porous carbon. The porous carbon nanospheres effectively address the low conductivity of Fe3O4 nanoparticles, while the ultra‐small Fe3O4 nanoparticles anchored on the carbon surface provide efficient catalytic sites for the ORR.