In Situ Symbiosis of Cerium Oxide Nanophase for Enhancing the Oxygen Electrocatalysis Performance of Single‐Atom Fe─N─C Catalyst with Prolonged Stability for Zinc–Air Batteries

Abstract The Fenton reaction, induced by the H 2 O 2 formed during the oxygen reduction reaction (ORR) process leads to significant dissolution of Fe, resulting in unsatisfactory stability of the iron–nitrogen‐doped carbon catalysts (Fe‐NC). In this study, a strategy is proposed to improve the ORR catalytic activity while eliminating the effect of H 2 O 2 by introducing CeO 2 nanoparticles. Transmission electron microscopy and subsequent characterizations reveal that CeO 2 nanoparticles are uniformly distributed on the carbon substrate, with atomically dispersed Fe single‐atom catalysts (SACs) adjacent to them. CeO 2 @Fe‐NC achieves a half‐wave potential of 0.89 V and a limiting current density of 6.2 mA cm −2 , which significantly outperforms Fe‐NC and commercial Pt/C. CeO 2 @Fe‐NC also shows a half‐wave potential loss of only 1% after 10 000 CV cycles, which is better than that of Fe‐NC (7%). Further, H 2 O 2 elimination experiments show that the introduction of CeO 2 significantly accelerate the decomposition of H 2 O 2 . In situ Raman spectroscopy results suggest that CeO 2 @Fe‐NC significantly facilitates the formation of ORR intermediates compared with Fe‐NC. The Zn–air batteries utilizing CeO 2 @Fe‐NC cathodes exhibit satisfactory peak power density and open‐circuit voltage. Furthermore, theoretical calculations show that the introduction of CeO 2 enhances the ORR activity of Fe‐NC SAC. This study provides insights for optimizing SAC‐based electrocatalysts with high activity and stability.