S. L. Zhang, Pengyang Jiang, Qiaoyun Wang, Caijin Huang, Kaining Ding
Abstract In recent years, the demand for catalytic devices in renewable energy applications has grown rapidly. HEMs characterized by their distinct atomic configurations, exhibit excellent chemical stability, corrosion resistance, mechanical properties, and favorable thermal stability, making them advantageous for modern catalytic technologies. This article summarizes the fundamental definition and synthetic approaches of HEMs and investigates the influencing factors of photocatalytic activity from four aspects: semiconductor band structure, charge carrier separation and migration characteristics, catalyst surface activity, and environmental parameters. Moreover, the design and preparation of HEM photocatalysts by adjusting component ratio, optimizing lattice defects, and regulating electronic structure are mainly introduced. Finally, the broad application prospects of HEMs in fields such as photocatalysis, energy conversion and storage are presented. Given the rapid development and transformative potential of HEMs in photocatalysis, a systematic review is essential to consolidate recent advances, clarify design principles, and guide future research toward efficient and stable photocatalytic systems.