Faceting Transition at the Oxide-Metal Interface: (13131) Facets on Cu(110) Induced by Carpet-Like Ceria Overlayer
Abstrakt
Structural transitions affect electronic structure of materials and consequently their catalytic properties. We report the observation of faceting of a low index metal surface at an oxide-metal interface in a catalytically relevant system of ceria on Cu(110).
We observe formation of (13 13 1) facets on the Cu(110) surface covered by ceria upon annealing above 500 degrees C. The faceting transition occurs in spite of a weak adsorbate-substrate interaction, which manifests itself in ceria adopting a carpet-like growth mode.
We rationalize the surface faceting under such conditions by oxide overlayer-induced modification of the roughening temperature of Cu(110). We describe the carpet-like ceria film in terms of elasticity theory and show that the specific structure of the ceria supported on Cu(13 13 1) can lead to a periodic modulation of the electronic structure of the ceria-copper interface.
The reported structural transition indicates that surface faceting of metal can occur at the oxide-metal interface at relatively low temperatures with possible consequences for the catalytic properties of the interface. The oxide overlayer induced faceting transition can be expected to occur for other oxide-metal combinations and, as such, has perspective applications in preparation of functional oxide-metal nanostructures.