Chemical Ordering of High-Entropy Nanomaterials for Pathway-Directed Electrocatalysis

Conspectus High-entropy nanomaterials (HEMs) have emerged as versatile electrocatalytic platforms, because their multielement compositions provide diverse electronic configurations and coordination environments. However, high configurational complexity alone does not define the catalytic sites. Differences in elemental interactions and reduction kinetics can lead to segregation, phase separation, and structural heterogeneity, while random site occupation complicates the identification of catalytic sites and structure–activity correlations. High-entropy chemical ordering (HECO) addresses this challenge by organizing selected elements over defined spatial scales while retaining the multielement diversity. Drawing on our studies and related works, this Account describes three connected strategies. Electrospinning-enabled coordination confinement uses metal–polymer coordination and a polymer-derived carbon matrix to establish homogeneous multielement phases and regulate atomic transport. Directional atomic migration organizes selected elements at surfaces and interfaces through segregation, exsolution, and migration trapping. Diffusion-mediated bulk ordering produces preferential occupation of crystallographic sublattices and long-range ordered high-entropy intermetallics (HEIs). Local electronic polarization and intermediate adsorption help determine the elementary steps favored at different sites, while structural evolution under operating conditions can modify these relationships. Spatial organization can influence the intermediate transfer, reaction selectivity, and competing pathways. These considerations can guide the design of new surface-, interfacial-, and bulk-ordered HEMs with catalytic functions tailored to pathway-directed electrocatalysis.