title: Growth and composition of nanostructured and nanoporous cerium oxide thin films on a graphite foil.
abstract: The morphology and composition of CeOx films prepared by r.f. magnetron sputtering on a graphite foil have been investigated mainly by using microscopy methods. This study presents the formation of nanocrystalline layers with porous structure due to the modification of a carbon support and the formation of cerium carbide crystallites as a result of the deposition process. Chemical analyses of the layers with different thicknesses performed by energy dispersive X-ray spectroscopy, electron energy loss spectroscopy and X-ray photoelectron spectroscopy have pointed to the reduction of the cerium oxide layers. In the deposited layers, cerium was present in mixed Ce(3+) and Ce(4+) valence. Ce(3+) species were located mainly at the graphite foil-CeOx interface and the chemical state of cerium was gradually changing to Ce(4+) going to the layer surface. It became more stoichiometric in the case of thicker layers except for the surface region, where the presence of Ce(3+) was associated with oxygen vacancies on the surface of cerium oxide grains. The degree of cerium oxide reduction is discussed in the context of particle size.
authors: Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University in Prague, V Holešovičkách 2, 180 00 Prague 8, Czech Republic. jaroslava.lavkova@gmail.com.
authors: Jaroslava
authors: J
authors: Lavkova
authors: Ivan
authors: I
authors: Khalakhan
authors: Mykhailo
authors: M
authors: Chundak
authors: Mykhailo
authors: M
authors: Vorokhta
authors: Valerie
authors: V
authors: Potin
authors: Vladimir
authors: V
authors: Matolin
authors: Iva
authors: I
authors: Matolinova