Strain-induced formation of arrays of catalytically active sites at the metal-oxide interface

Ultrathin layers of cerium oxide on a Rh(1 1 1) surface develop an ordered array of surface defects when subjected to reducing conditions by annealing in vacuum. We show, using scanning tunneling microscopy images with atomic resolution and ab initio density functional theory calculations, that the defects are related to oxygen vacancies. It is suggested that the defect formation is facilitated by the lattice mismatch between the oxide overlayer and the metal substrate. This demonstrates an interface strain-induced mechanism for the formation of arrays of catalytically active centers at a metal-oxide interface. (C) 2004 Elsevier B.V. All rights reserved.