Advanced high-entropy nanoalloys toward renewable energy electrocatalysis

Abstract

Alloying has long been recognized as one of the most promising strategies for designing high-performance metal-based electrocatalysts. However, the limited range of available elemental species in conventional alloys often restricts the continuous-tuning of the surface electronic structure of metal catalysts. High-entropy nanoalloys (HENAs), with their diverse compositional and structural characteristics, offer a pathway to overcome the limitations of traditional binary or ternary alloys, providing adsorption/desorption energies towards reaction intermediates closer to the optimum. Therefore, HENAs have emerged as promising candidates for electrocatalytic reactions integral to various renewable energy technologies, such as fuel cells, water electrolyzers, etc., and have witnessed remarkable progress in recent years. This review summarizes recent advances in HENA-based electrocatalysts for energy-related applications and highlights the crucial role of rational structural design in enhancing their performance. It begins with an introduction to the fundamental concepts, physicochemical properties, and structural characterizations of HENAs. Then, we categorize state-of-the-art HENA electrocatalysts based on their dimensionality, with particular emphasis on understanding their formation mechanisms at the nanoscale and atomic-scale. Furthermore, we discuss the rational underlying the structural regulation of electronic structures, electrocatalytic properties, and functional mechanisms of HENAs in several key electrocatalytic reactions. Finally, we outline the remaining challenges and future perspectives in this field, aiming to inspire the development of more advanced HENA-based catalysts to touch the ceiling of electrocatalytic activity and stability.