CO Oxidation on Gold-Supported Iron Oxides: New Insights into Strong Oxide–Metal Interactions

Very active FeO x –Au catalysts for CO oxidation are obtained after depositing nanoparticles of FeO, Fe 3 O 4, and Fe 2 O 3 on a Au(111) substrate. Neither FeO nor Fe 2 O 3 is stable under the reaction conditions. Under an environment of CO/O 2, they undergo oxidation (FeO) or reduction (Fe 2 O 3 ) to yield nanoparticles of Fe 3 O 4 that are not formed in a bulk phase. Using a combined experimental and theoretical approach, we show a strong oxide–metal interaction (SOMI) between Fe 3 O 4 nanostructures and Au(111), which gives the oxide special properties, allows the formation of an active phase, and provides a unique interface to facilitate a catalytic reaction. Our work highlights the important role that the SOMI can play in enhancing the catalytic performance of the oxide component in metal–oxide catalysts.