Engineering Active CeO ₂ /Fe ₃ C Interfacial Sites to Generate High‐Charge‐Density Fe for Enhanced Oxygen Reduction Reaction Efficiency

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.