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.