Interfacial Curvature-Induced Electronic Modulation in Carbon-Encapsulated Fe ₃ C for the Oxygen Reduction Reaction

Precise control of the interfacial electronic structure is crucial for designing high-performance metal carbide catalysts. Herein, we report an N-doped carbon-encapsulated Fe3C catalyst (Fe3C@NC), in which the intrinsic curvature of the carbon shell induces significant interfacial electronic modulation. Structural characterization and density functional theory (DFT) calculations reveal that curvature-driven electron redistribution optimizes Fe 3d states and enhances oxygen adsorption and conversion to *OOH at the active sites. This electronic regulation promotes the dissociative oxygen reduction pathway under alkaline conditions, leading to a high onset potential (Eonset: 1.03 V vs RHE) and half-wave potential (E1/2: 0.90 V vs RHE) with excellent durability. When tested in a Zn–air battery, Fe3C@NC achieves a high peak power density of 187.5 mA cm–2, demonstrating the practical relevance of the catalyst. These results highlight interfacial curvature as an important structural parameter for tuning the electronic properties of metal carbides and provide new insights into the rational design of advanced inorganic electrocatalysts.