Size of cerium dioxide support nanocrystals dictates reactivity of highly dispersed palladium catalysts

The catalytic performance of heterogeneous catalysts can be tuned by modulation of the size and structure of supported transition metals, which are typically regarded as the active sites. In single-atom metal catalysts, the support itself can strongly affect the catalytic properties. Here, we demonstrate that the size of cerium dioxide (CeO2) support governs the reactivity of atomically dispersed palladium (Pd) in carbon monoxide (CO) oxidation. Catalysts with small CeO2 nanocrystals (similar to 4 nanometers) exhibit unusually high activity in a CO-rich reaction feed, whereas catalysts with medium-size CeO2 (similar to 8 nanometers) are preferred for lean conditions. Detailed spectroscopic investigations reveal support size-dependent redox properties of the Pd-CeO2 interface.

Automated summary

The size and structure of supported transition metals, which act as active sites, can be adjusted to optimize the catalytic performance of heterogeneous catalysts. In single-atom metal catalysts, the support itself has a significant impact on catalytic properties. In this study, we demonstrate that the size of the CeO2 support determines the reactivity of atomically dispersed Pd in CO oxidation. Small CeO2 nanocrystals (around 4 nanometers) show high activity in CO-rich conditions, while medium-sized CeO2 (around 8 nanometers) is preferred for lean conditions. Detailed spectroscopic investigations reveal size-dependent redox properties at the Pd-CeO2 interface.