Emerging High-Entropy Alloy Electrocatalysts for Water Splitting: From Fundamentals to Practical Applications

Abstract

High-entropy alloys (HEAs) have recently emerged as a promising category of electrocatalysts for water electrolysis, attributable to their distinctive multi-principal elements and entropy stabilized structures. In comparison with conventional catalysts, HEAs present unparalleled compositional flexibility and synergistic effects.Facilitating the simultaneous optimization of catalytic activity, stability, and cost, the three factors that traditionally display intrinsic trade-offs in water splitting catalysis. In this review, we systematically summarize the recent advancements in HEAs electrocatalysts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting. Emphasis is laid on the fundamental design principles of HEAs, encompassing high-entropy effects, electronic structure modulation, lattice distortion, and synergistic interactions among constituent elements, as well as their functions in regulating reaction energetics and durability under harsh electrolysis conditions. We further deliberate on the applications of HEAs in complex electrochemical environments, such as high-current-density operation and seawater electrolysis. Finally, future perspectives regarding data-driven catalyst design, advanced characterization, and industrially relevant implementation are presented, highlighting the potential of HEAs to enable cost-effective and large-scale green hydrogen production.