Atomically Dispersed Pd–O Species on CeO(2)(111) as Highly Active Sites for Low-Temperature CO Oxidation

[Image: see text] Ceria-supported Pd is a promising heterogeneous catalyst for CO oxidation relevant to environmental cleanup reactions. Pd loaded onto a nanorod form of ceria exposing predominantly (111) facets is already active at 50 °C. Here we report a combination of CO-FTIR spectroscopy and theoretical calculations that allows assigning different forms of Pd on the CeO(2)(111) surface during reaction conditions. Single Pd atoms stabilized in the form of PdO and PdO(2) in a CO/O(2) atmosphere participate in a catalytic cycle involving very low activation barriers for CO oxidation. The presence of single Pd atoms on the Pd/CeO(2)-nanorod, corroborated by aberration-corrected TEM and CO-FTIR spectroscopy, is considered pivotal to its high CO oxidation activity.