Probing Catalytic Sites and Adsorbate Spillover on Ultrathin FeO<sub>2-<i>x</i></sub> Film on Ir(111) during CO Oxidation.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38377596.
- Also identified by DOI 10.1021/acsnano.3c11400 and PMC identifier 10919091.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The spatially resolved identification of active sites on the heterogeneous catalyst surface is an essential step toward directly visualizing a catalytic reaction with atomic scale. To date, ferrous centers on platinum group metals have shown promising potential for low-temperature CO catalytic oxidation, but the temporal and spatial distribution of active sites during the reaction and how molecular-scale structures develop at the interface are not fully understood. Here, we studied the catalytic CO oxidation and the effect of co-adsorbed hydrogen on the FeO<sub>2-<i>x</i></sub>/Ir(111) surface. Combining scanning tunneling microscopy (STM), isotope-labeled pulse reaction measurements, and DFT calculations, we identified both FeO<sub>2</sub>/Ir and FeO<sub>2</sub>/FeO sites as active sites with different reactivity. The trilayer O-Fe-O structure with its Moiré pattern can be fully recovered after O<sub>2</sub> exposure, where molecular O<sub>2</sub> dissociates at the FeO/Ir interface. Additionally, as a competitor, dissociated hydrogen migrates onto the oxide film with the formation of surface hydroxyl and water clusters down to 150 K.