Nanoscale Fe3O4 Electrocatalysts for Oxygen Reduction Reaction

This study presents a straightforward hydrothermal synthesis approach to fabricate uniform and highly dispersed nanoscale Fe3O4 electrocatalysts for the oxygen reduction reaction (ORR). FeSO4·7H2O is used as the precursor, and sodium dodecyl sulfate (SDS) is incorporated as a dispersing agent to optimize particle size and dispersion. The SDS concentration plays a crucial role in controlling the particle size and distribution, with higher SDS concentrations resulting in smaller, well-dispersed particles (30–40 nm), compared to the agglomerated particles formed without SDS. The Fe3O4 catalyst demonstrates significant enhancement in ORR performance, with a half-wave potential of 0.091 V vs. Hg/HgO and a limiting diffusion current density of −5.50 mA cm2, surpassing the performance of agglomerated Fe3O4 and approaching that of state-of-the-art 20% Pt/C catalysts. Additionally, the Fe3O4 catalyst exhibits superior stability and resistance to methanol and CO poisoning, presenting a promising alternative to platinum-based catalysts for ORR applications. This work introduces an efficient approach for the synthesis of high-performance and evenly distributed Fe3O4 electrocatalysts, offering a new pathway for the development of metal oxide-based ORR catalysts with enhanced activity and durability.