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
Hao Luo, Jiajun Wang, Shiyu Zhang, Buwei Sun, Zanyu Chen, Xixi Ren, Ziyi Luo, Xiaopeng Han, Wenbin Hu
Abstract
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.