RHEED structural study of the novel tin-cerium oxide catalyst

We present our study of Sn interaction with CeO2 (1 1 1) thin film supported by a Cu (1 1 1) single crystal. After deposition of metallic tin, tin-cerium mixed oxide is formed in the subsurface region by substitution of cerium atoms by tin in the cerium oxide crystal lattice. This process leads to transformation of the original fluorite structure of cerium dioxide to a simple cubic structure. The excessive metallic tin remaining on the surface forms three populations of small epitaxial clusters with tetragonal structure and the (0 1 0) crystallographic plane parallel to the surface. Two of these populations are favored over the third one, due to their better accommodation to the substrate lattice. After annealing the sample at 400 °C in oxygen atmosphere the metallic Sn clusters disappear and a very thin film of polycrystalline tin dioxide is formed.