(763a) Adsorbate-Mediated Strong Metal-Support Interactions in Oxide Supported Rh Catalysts

Optimization of supported metal catalysts predominantly focuses on engineering the metal site, where physical insights based on extensive theoretical and experimental contributions have enabled rational design of active sites. While it is well known that supports can influence the catalytic properties of metals, physically transparent insights into how metal-support interactions can be exploited to optimize metal active site properties are lacking. We utilize in-situ FTIR/XAS/EELS spectroscopy and in-situ HRTEM microscopy to identify and characterize a support-effect in oxide-supported heterogeneous Rh catalysts, where strongly bound adsorbates (HCO_x) on reducible oxide supports (TiO₂ and Nb₂O₅) induce oxygen-vacancy formation in the support, causing HCO_x functionalized support encapsulation of Rh nanoparticles. The encapsulation layer is permeable to reactants, stable under reaction conditions, and strongly influences the catalytic properties of Rh, enabling rational and dynamic tuning of CO₂ reduction selectivity.