High-entropy catalysts: new opportunities toward excellent catalytic activities

High-entropy catalysts (HECs) have been increasingly used in various applications in recent years. Owing to their multi-element composition and high-entropy mixing structure, HECs exhibit excellent catalytic performance in thermocatalysis, electrocatalysis, and photocatalysis. This comprehensive review focuses on the synthesis and catalytic applications of high-entropy alloys (HEAs), high-entropy oxides (HEOs), high-entropy sulfides (HESs), and other high-entropy catalytic systems. In this review, we point out several issues that require further exploration, including the controllable synthesis of HECs, identification of active centers, and regulation of elemental composition and structure of HECs. We hope that this review can help to further advance the development of HECs, in terms of optimizing the catalytic activities of HECs. Moreover, the "high-entropy" design concept behind these materials may also provide insights and solutions for addressing the challenges encountered in traditional simple systems. High-entropy catalysts (HECs) have been increasingly used in various catalytic applications.