High-entropy alloys in water electrolysis: Recent advances, fundamentals, and challenges

As a clean energy carrier, hydrogen energy has become part of the global clean energy strategy and one of the necessary routes to achieve global carbon neutrality. Driven by renewable electricity, water electrolysis promises to be an ideal long-term hydrogen production method that can realize net zero carbon emissions. Compared with conventional alloys, high-entropy alloys (HEAs) have much more catalytic active sites due to their unique structural features including occupation disorder and lattice ordering. They have various promising applications in the field of hydrolysis catalysts. Herein, in this review, the mechanisms of electrolysis of water, catalytic principles of HEAs in hydrolysis processes and latest research progress of HEAs as water electrolysis catalysts are summarized. We also provide perspectives on the difficulties and potential linked to novel HEA design approaches in this attractive sector, with a focus on the connection between both the surface morphology and the catalysis activity. The compositions and possible applications of HEAs in water electrolysis and other emerging fields are outlined. © 2023, Science China Press.