Electron Transfer from Encapsulated Fe<sub>3</sub>C to the Outermost N‐Doped Carbon Layer for Superior ORR
Javier Quílez‐Bermejo, Ayoub Daouli, Sergio García‐Dalí, Yingdan Cui, Andrea Zitolo, Jimena Castro‐Gutiérrez, Mélanie Emo, M.T. Izquierdo, William E. Mustain, Michaël Badawi, Alain Celzard, Vanessa Fierro
Abstract
Abstract Encapsulating Fe 3 C in carbon layers has emerged as an innovative strategy for protecting Fe 3 C while preserving its high oxygen reduction activity. However, fundamental questions persist regarding the active sites of encapsulated Fe 3 C due to the restricted accessibility of oxygen molecules to the metal sites. Herein, the intrinsic electron transfer mechanisms of Fe 3 C nanoparticles encapsulated in N‐doped carbon materials are unveiled for oxygen reduction electrocatalysis. The precision‐structured C 1 N 1 material is used to synthesize N‐doped carbons with encapsulated Fe 3 C, significantly enhancing catalytic activity (E ONSET = 0.98 V) and achieving near‐100% operational stability. In anion‐exchange membrane fuel cells, an excellent peak power density of 830 mW cm −2 is reached at 60 °C. The experimental and computational results revealed that the presence of Fe 3 C cores dynamically triggers electron transfer to the outermost carbon layer. This phenomenon amplifies the oxygen reduction reaction performance at N sites, contributing significantly to the observed catalytic enhancement.