Multivariate Synergy and Two-Dimensional Confinement: Research Progress and Opportunities of Two-Dimensional High-Entropy Alloys.

As an emerging material system that integrates high-entropy alloys with two-dimensional (2D) materials, 2D high-entropy alloys (HEAs) have attracted significant research interest. They combine the compositional tunability and multivariate synergy of HEAs with the quantum confinement and high specific surface area of 2D materials. This review comprehensively summarizes recent advances in 2D HEAs. We begin by elaborating on their fundamental concepts, structural characteristics, and performance advantages. Subsequently, we delve into various synthesis strategies, such as chemical vapor deposition, solvothermal methods, template-assisted approaches, and space-confined chemical vapor transport, critically analyzing their strengths and limitations. The review also provides a detailed analysis of key structural features, including crystal structure, elemental distribution, and surface morphology. Furthermore, we highlight the promising applications of 2D HEAs in electrocatalysis (e.g., hydrogen evolution, oxygen evolution, and oxygen reduction reactions), energy storage (batteries and supercapacitors), sensing, and organic catalysis. Finally, we discuss the current challenges and future research directions, aiming to offer a systematic reference for further development and practical application of 2D HEA materials.