Engineering Active CeO <sub>2</sub> /Fe <sub>3</sub> C Interfacial Sites to Generate High‐Charge‐Density Fe for Enhanced Oxygen Reduction Reaction Efficiency
Peng Wang, Yao Xü, L. Yan, Puyang Xie, Haitao Li, Yanhong Zhao, Yuhai Dou, Fengyu Li, Jian Liu
Abstract
Abstract The practical application of Fe 3 C‐based catalysts is hindered by two major challenges: the continuous dissolution of Fe atoms and the strong adsorption of oxygen intermediates. To overcome these limitations, a novel rare earth (RE) oxide/iron carbide heterostructure is designed, featuring abundant active CeO 2 /Fe 3 C interfacial sites anchored on N‐doped carbon substrates (CeO 2 /Fe 3 C@N‐C). The CeO 2 /Fe 3 C@N‐C catalyst exhibits exceptional alkaline oxygen reduction reaction (ORR) performance, with a half‐wave potential ( E 1/2 ) of 0.926 V and remarkable durability, sustaining over 20 000 cycles with minimal degradation. These metrics surpass those of commercial 20% Pt/C and most reported Fe 3 C‐based electrocatalysts. When applied as a cathode catalyst in Zn–air batteries (ZABs), CeO 2 /Fe 3 C@N‐C achieves a high‐power density of 204 mW cm⁻ 2 , demonstrating its practical potential. Through a combination of experimental characterization and density functional theory (DFT) calculations, the mechanistic origins of enhanced performance is uncovered. CeO 2 acts as an electron donor, inducing electron redistribution at the CeO 2 /Fe 3 C interface and resulting in electron accumulation at the Fe active sites. This work not only demonstrates a high‐performance ORR catalyst but also provides fundamental insights into the role of RE oxides in enhancing Fe 3 C‐based electrocatalysts. The findings offer a strategic pathway for designing advanced energy conversion materials with improved activity, stability, and efficiency.