Navigating Complexity to Design Nanostructured High‐Entropy Alloy Catalysts

Abstract Nanostructured high‐entropy alloys (nHEAs) are a prominent subclass of high‐entropy materials (HEMs). They exhibit a high specific surface area and vast morphological space enabled by their nanoscale dimensions, making them highly promising catalytic materials. Despite these merits, the nanostructure also introduces additional structural complexities and increases reconstruction during catalysis, which pose major challenges to their rational design. In this review, this inherent duality of nHEAs in catalysis is highlighted, and a comprehensive overview of recent advances aimed at addressing their structural complexities is provided. It is begun by elucidating the origins of these complexities, which mainly arise from the nearly infinite compositional possibilities, diverse atomic stacking configurations, and the intricate structures at the (sub)nanometer scale. Then, state‐of‐the‐art tools and methods are presented for managing these complexities and accelerating the discovery of next‐generation nHEAs catalysts, including high‐throughput synthesis and screening, first‐principle calculations, and machine learning. More importantly, emerging design principles are summarized that move beyond simple, trial‐and‐error compositional and configurational tuning, toward holistic and systematically integrated design strategies. This review delves into the intricate complexities of nHEAs and their corresponding strategies, aiming to provide valuable insights for their rational design in a variety of chemical transformations.