Rh‐based high‐entropy alloy nanoclusters unlock superior hydroformylation performance through multi‐site synergy

Abstract Rh‐metal clusters, characterized by an ultrahigh surface‐to‐volume ratio approaching 100%, serve as pivotal active centers in hydroformylation. However, such Rh clusters containing numerous Rh–Rh metallic bonds typically exhibit limited selectivity for oxygenated products. Herein, we report the architectural engineering of high‐entropy‐alloy Rh nanoclusters (Rh‐HEACs) confined within MCM‐41 mesopores, achieving a remarkable styrene turnover frequency (TOF) of 7377.0 h −1 , 3‐fold over that of RhMg@MCM‐41 (2675.0 h −1 ). The Rh‐HEA architecture not only reduces the surface density of Rh–Rh assemblies but also modifies adsorption behavior through its distinctive electronic configuration. Specifically, the interfacial coupling among Rh, Cu, Co, Zn, and Mg induces electron transfer from the transition metals to Rh centers. This unique electronic structure weakens CO binding while preserving styrene affinity, optimizing reaction pathways. Our findings convincingly demonstrate that HEA nanoclusters bridge the critical performance gap between heterogeneous and homogeneous Rh‐based catalytic systems in hydroformylation applications.