Recent progress in high-entropy alloys for catalysts: synthesis, applications, and prospects

In recent years, high-entropy alloys (HEAs) have been attracting great interests in the development and application of electro/thermo-catalytic clean energy conversion due to their unique microstructures, impressive thermal stability and excellent catalytic activities for various reactions. Recently, much effort has been devoted to the synthesis and catalytic applications of HEAs. It is of great significance and urgency to explore new HEAs for the applications in clean energy conversion and beyond. In this review, we discuss the recent development of HEAs in terms of their synthesis methodologies and catalytic applications. Four novel synthetic strategies relating to HEAs are discussed, which include carbothermal shock, fast moving bed pyrolysis (FMBP), electro-shock, and theoretical prediction methods. Importantly, we highlight the importance of computationally aided methods, e.g. density functional theory (DFT) calculations, high-throughput, and machine learning (ML), to the discovery and design of HEAs. In addition, we focus on the applications of HEAs in the field of catalytic clean energy conversion reactions, including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), and ammonia (NH3) decomposition. Furthermore, the prospects and future opportunities for utilization of HEAs from the experimental and theoretical aspects as well as their future applications in various catalytic processes have been thoroughly discussed.