A disordered oxide as an active phase during CO catalytic oxidation on Ru(0001)

Abstract

The identification of the active phase of a catalyst under operando conditions is probably the most relevant task in basic catalysis research. In this respect, the Ru(0001) surface during CO oxidation is a traditional studied model, for both its importance in applied catalysis and for its peculiar behavior. In this work, we study the CO catalytic oxidation reaction on flat and defective Ru(0001) surfaces, concluding that the highest activity is achieved in oxidizing conditions when a disordered and thin Ru oxide is formed at the surface. Also, we find that in defective surfaces, with a high density of surface steps, this reaction is enhanced, related to the facile sub-surface incorporation of atomic oxygen and to the easier formation of the oxide. Thus, the CO catalytic oxidation on Ru(0001) is a structure-sensitive reaction, being active on the surface of the oxide formed in reaction conditions.