A Triatomic Fe ₂ Co Catalyst for Oxygen Electrocatalysis

ABSTRACT The development of uniformly distributed Fe‐N/C catalysts opens up possibilities for replacing precious metals in the oxygen reduction reaction (ORR). However, the stability is relatively poor due to Fenton‐like reactions. In this study, we employ density functional theory (DFT) calculations to demonstrate that heteronuclear Fe 2 Co triatomic clusters is closest to the vertices of the ΔG *OOH , ΔG *OH, and U L volcano diagrams. Guided by the theoretical insights, we synthesize a series of triangular Fe 2 M (M = Fe, Mn, Co, and Ni) triatomic sites anchored on nitrogen‐doped hollow carbon nanocages (HNC) via a strain‐confined thermal imprinting strategy. Fe 2 CoN 6 /HNC as the optimal ORR catalyst, achieves high half‐wave potentials of 0.971 V in alkaline media and 0.80 V in acidic media, significantly outperforming commercial Pt/C. DFT calculations combined with in situ XAS and Raman spectra demonstrate that the triangular Fe 2 Co architecture drives charge redistribution, wherein Fe 2 atoms function as the primary active sites while the Co atom acts as an electronic modulator to tailor the local electronic structure, downshifting the d‐band center and weakening * OH adsorption to promote the 4e − ORR pathway. This work provides atomic‐level design strategies for favorably tuning scaling relations in multi‐atom catalysts, tackling the key stability concerns of Fe‐N/C systems.