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XPS investigation of surface oxidation and reduction in nanocrystalline Ce x La 1 − x O 2 − y
Author(s) -
Trudeau M. L.,
Tschöpe A.,
Ying J. Y.
Publication year - 1995
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.740230405
Subject(s) - nanocrystalline material , x ray photoelectron spectroscopy , stoichiometry , catalysis , analytical chemistry (journal) , redox , chemistry , materials science , inorganic chemistry , crystallography , chemical engineering , engineering , biochemistry , chromatography
Inert gas condensation was used to generate nanocrystalline La‐doped CeO 2 − x . Non‐stoichiometric CeO 2 − x ‐based materials were found to be excellent catalysts in recent studies for the selective reduction of SO 2 . To understand better the stoichiometry‐related catalytic properties, the surface chemistry of nanocrystalline La‐doped CeO 2 − x was investigated through in situ oxidation‐reduction thermal treatments. Oxidation in CO 2 and reduction in H 2 atmospheres were performed between 30°C and 600°C in a reaction chamber connected to a x‐ray photoelectron spectrometer analytical chamber. Curve fitting and target factor analysis were used to obtain a semi‐quantitative measurement of the transformation between +3 and +4 oxidation states during these reactions. Target factor analysis was found to be a very useful tool for analyzing the contributions corresponding to Ce +3 and Ce +4 .