Evidence for the stabilization of FeN4 sites by Pt particles during acidic oxygen reduction
- Nicolas A. Ishiki
- Keyla Teixeira Santos
- Nicolas Bibent
- Kavita Kumar
- Ina Reichmann
- Yu-Ping Ku
- Tristan Asset
- Laetitia Dubau
- Michel Mermoux
- Hongxin Ge
- Sandrine Berthon-Fabry
- Viktoriia A. Saveleva
- Vinod K. Paidi
- Pieter Glatzel
- Andrea Zitolo
- Tzonka Mineva
- Hazar Guesmi
- Serhiy Cherevko
- Edson A. Ticianelli
- Frédéric Maillard
- Frédéric Jaouen
2025-07-11
While Fe–N–C materials have shown promising initial oxygen reduction reaction (ORR) activity, they lack durability in acidic medium. Key degradation mechanisms include FeN 4 site demetallation and deactivation by reactive oxygen species. Here we show for mainstream Fe–N–Cs that adding 1 wt.% Pt nanoparticles via a soft polyol method results in well-defined and stable Pt/Fe–N–C hybrids. The Pt addition strongly reduces the H 2 O 2 production and Fe leaching rate during ORR, while post mortem Mössbauer spectroscopy reveals that the highly active but unstable Fe(III)N 4 site is partially stabilized. The similar H 2 O 2 electroreduction activity of Pt/Fe–N–C and Fe–N–C and other analyses point toward a long-distance electronic effect of Pt nanoparticles in stabilizing FeN 4 sites. Computational chemistry reveals that spin polarization of distant Pt atoms mitigates the structural changes of FeN 4 sites upon adsorption of oxygenated species atop Fe, especially in high-spin state.