Electronegativity of Doped Metals Determines the Stability of PtFeM Intermetallic Catalysts for Oxygen Reduction Reaction

The long-term stability of Pt-based alloy catalysts in fuel cells is severely limited by transition metal leaching, which degrades the oxygen reduction reaction (ORR) performance. Herein, we demonstrate that the stability of ternary PtFe0.5M0.5 (M = 3d transition metals) catalysts is primarily governed by the electronegativity of M. Density functional theory calculations and experimental results reveal a strong correlation between transition metal retention rates after accelerated degradation tests and the electronegativity of M-elements: PtFe doped with high-electronegativity metals (Ni, Cu, Co) exhibits severe ORR mass activity loss (∼30%), while the medium/low-electronegativity variants show remarkable retention (e.g., 89.2% for PtFe0.5Sc0.5). The low-electronegativity M suppresses both Fe and M leaching by stabilizing Pt valence states through enhanced charge accumulation, rather than via traditional sacrificial anode mechanism, as evidenced by electron localization function analysis and structural characterizations. This study establishes electronegativity as a key descriptor of durable Pt-based ORR catalyst design for fuel cell applications.