High‐Entropy Materials for Water Electrolysis

Green hydrogen production by renewables‐powered water electrolysis holds the key to energy sustainability and a carbon‐neutral future. The sluggish kinetics of water‐splitting reactions, namely, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), however, remains a bottleneck to the water electrolysis technology. High‐entropy materials, due to their compositional flexibility, structural stability, and synergy between various elemental components, have recently aroused considerable interest in catalyzing the water‐splitting reactions. Herein, a timely review of the recent achievements is provided in high‐entropy materials for water electrolysis. An overview of different kinds of high‐entropy materials for catalyzing the HER and OER half‐reactions is introduced, followed by a discussion of theoretical and experimental efforts in understanding the fundamental origins of the enhanced catalytic performance observed on high‐entropy catalysts. Various materials design strategies, including control of size and shape, construction of a porous structure, engineering of defect, and formation of hybrid/composite structure, to develop high‐entropy catalysts with improved catalytic performance are highlighted. Finally, the remaining challenges are pointed out and the corresponding perspectives to address these challenges are put forward to promote the development of the research field of high‐entropy water‐splitting catalysts.