Yin, HaoYan, Yu-WeiFang, WeiBrune, Harald2024-03-182024-03-182024-03-182024-02-2010.1021/acsnano.3c11400https://infoscience.epfl.ch/handle/20.500.14299/206566WOS:001173730000001The 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 FeO2-x /Ir(111) surface. Combining scanning tunneling microscopy (STM), isotope-labeled pulse reaction measurements, and DFT calculations, we identified both FeO2/Ir and FeO2/FeO sites as active sites with different reactivity. The trilayer O-Fe-O structure with its Moire pattern can be fully recovered after O-2 exposure, where molecular O-2 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.Physical SciencesTechnologyIron OxidesCo OxidationSurface ScienceHydrogen SpilloverModel Catalysttext::journal::journal article::research article