Single‐Nanoparticle Collision Revealing High‐Entropy Suppression of Elemental Segregation in Multi‐Element Alloys During Oxygen Evolution Reaction

In the oxygen evolution reaction (OER), the structural reconstruction and elemental segregation of alloy catalysts are key factors influencing their activity and stability, while the irreversible structural evolution induced by high current density is the primary issue leading to performance degradation. Herein, we designed a multi-element alloy nanoparticle (MEA-NP) model electrocatalyst from binary (FeIr) to quinary alloy (FeCoNiIrRu), modulating the configuration entropy to explore its influence on structural stability. The single-nanoparticle collision (SNC) based on scanning electrochemical cell microscopy (SECCM) was employed to facilitate efficient mass transfer and ultrahigh current density, thereby accelerating structural evolution during OER. By combining multidimensional feature extraction and clustering analysis of transient signals, it was found that increasing the number of constituent elements improves the structural stability under OER conditions, and high entropy effectively suppresses elemental segregation. Transmission electron microscopy (TEM), in situ Raman spectroscopy, and density functional theory (DFT) calculations further confirmed the advantages of the quinary alloy in terms of structural homogeneity and stability. This study established a statistical correlation between elemental segregation and single-particle transient OER signals, proposed a strategy similar to "accelerated testing under extreme conditions", providing new insights for the mechanistic study and rational design of OER catalysts.