Cluster Density-Dependent Electronic Metal–Support Interactions in Rh/CeO₂ for Enhanced Styrene Hydroformylation

Electronic metal-support interactions (EMSI) play a critical role in determining the performance of supported noble metal catalysts. While conventional strategies focus on modulating the size of noble metals or the properties of supports, the influence of the metal cluster density on EMSI remains unexplored. Herein, we demonstrate that precise control over Rh cluster density on CeO₂ nanorods (NR-CeO₂) provides a powerful handle to systematically tune interfacial charge transfer, thereby establishing a negative correlation between Rh cluster density and its electron richness. Low-density Rh clusters exhibit significantly enhanced electron donation from NR-CeO₂, inducing an upward shift in the <i>d</i>-band center of Rh clusters and thus achieving a turnover frequency (TOF) of 603 h^-1 for styrene hydroformylation at 70 °C. This study introduces cluster density engineering as a novel and effective strategy for optimizing EMSI, complementing traditional size- and support-driven approaches.