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First stages of growth of cerium oxide deposited on alumina and reduced titania surfaces
Author(s) -
Mansilla C.,
Yubero F.,
Zier M.,
Reiche R.,
Oswald S.,
Holgado J. P.,
Espinós J. P.,
GonzálezElipe A. R.
Publication year - 2006
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.2269
Subject(s) - x ray photoelectron spectroscopy , cerium oxide , cerium , oxide , nucleation , deposition (geology) , substrate (aquarium) , materials science , microstructure , chemistry , analytical chemistry (journal) , chemical engineering , metallurgy , environmental chemistry , paleontology , oceanography , organic chemistry , sediment , biology , geology , engineering
Abstract We have studied the first nucleation steps and the chemical interactions of small amounts of cerium oxide deposited on two surfaces with different chemical nature, alumina and a partially reduced titania. Cerium oxide was deposited by electron bombardment of CeO 2 pellets in ultra‐high vacuum conditions. All experiments were done in situ in order to avoid contamination related to exposure to air. The relative amounts of Ce 3+ and Ce 4+ species present at the successive deposition steps have been quantified. It is found that for initial steps of deposition, high amounts of Ce 3+ are stabilised at the CeO x /TiO x interface, while an approximately even mixture of Ce 3+ and Ce 4+ species appear at the CeO x /Al 2 O 3 interface. Thicker deposits are characterised by the presence of only Ce 4+ species independently of the substrate. It is found that cerium oxide grows in the form of islands on both substrates. These islands are taller in the case of deposition on reduced titania than on alumina. This result is confirmed by both angle resolved X‐ray photoelectron spectroscopy (XPS) and inelastic XPS peak shape analysis. The correlation between the growing microstructure and the chemical interaction at the interfaces is discussed. Copyright © 2006 John Wiley & Sons, Ltd.