关键词: 氧还原反应, Fe-N-C, 杂原子掺杂, 电子调控, 氧传质

Abstract: Fe-N-C catalysts have long suffered from kinetically sluggish oxygen reduction reaction (ORR) due to excessive adsorption strength toward oxygen intermediates and low site utilization. Heteroatom doping effectively accelerates ORR reaction kinetics through electronic structure modulation of metal sites for optimal intermediate adsorption, while chemical vapor deposition (CVD) enhances the turnover frequency (TOF) of active sites. Herein, we develop an FeSNC catalyst featuring abundant FeS₁N₄ sites via a dual-precursor CVD strategy. Experimental and theoretical analyses reveal that S incorporation disrupts the symmetric coordination of active sites, which optimizes OH* adsorption energies from 0.212 eV to 1.194 eV. Moreover, the TOF increased from 1.98 e^-1·site^-1·s^-1 to 6.32 e^-1·site^-1·s^-1, significantly enhancing the intrinsic activity of the catalyst. More notably, the hydrophilic character of S-containing species substantially improved hydrophilicity in the S-doped catalyst, thereby promoting mass transport of oxygen and proton delivery. As a result, FeSNC catalyst exhibits an extremely high half-wave potential of 0.863 V in 0.1 M HClO₄ and achieves a peak power density of 1.2 W·cm^-2 in H₂-O₂ PEMFCs. This work highlight the critical role of coordination engineering.

Key words: Oxygen reduction reaction, Fe-N-C, Heteroatom doping, Electronic regulation, Mass transport