TY - JOUR
T1 - Oxygen nonstoichiometry of the perovskite-type oxides BaCe0.9M0.1O3 - δ (M{double bond, short}Y, Yb, Sm, Tb, and Nd)
AU - Oishi, Masatsugu
AU - Yashiro, Keiji
AU - Sato, Kazuhisa
AU - Mizusaki, Junichiro
AU - Kitamura, Naoto
AU - Amezawa, Koji
AU - Kawada, Tatsuya
AU - Uchimoto, Yoshiharu
PY - 2008/6/30
Y1 - 2008/6/30
N2 - The oxygen nonstoichiometry, δ, of B-site doped BaCeO3 - δ under dry condition was determined as a function of oxygen partial pressures, PO2, between 1 bar and 10- 4 bar and temperatures between 773 K and 1373 K. The variation of δ in BaCe0.9Y0.1O3 - δ, BaCe0.9Yb0.1O3 - δ, BaCe0.9Sm0.1O3 - δ and BaCe0.9Tb0.1O3 - δ was very small through the experimental conditions. This indicates that charge imbalance due to the trivalent dopants is compensated essentially by the oxygen vacancy formation. A large variation was found for δ of BaCe0.9Nd0.1O3 - δ by PO2 and temperature. This result indicates that the valence of the metal elements change under the experimental conditions. The X-ray absorption spectroscopy (XAS) measurement was carried out to examine the valence of the B-site elements of BaCe0.9Nd0.1O3 - δ. The samples of different δ were prepared. From the XANES spectra of Ce and Nd, no spectra change for Ce L3-edge was observed, while spectra change was observed for Nd L3-edge and L2-edge. This indicates that the valence of Ce stay unchanged, while the valence of Nd may be changed by the different δ conditions. The measured δ of BaCe0.9Nd0.1O3 - δ was analyzed by considering the valence change of neodymium. By considering the defect equilibrium among Nd′Ce, Nd×Ce, VO••, and OO×, the change of δ against PO2 was well explained by assuming the defect equilibrium frac(1, 2) O2 + VO• • + 2NdCe' = OO× + 2NdCe×.
AB - The oxygen nonstoichiometry, δ, of B-site doped BaCeO3 - δ under dry condition was determined as a function of oxygen partial pressures, PO2, between 1 bar and 10- 4 bar and temperatures between 773 K and 1373 K. The variation of δ in BaCe0.9Y0.1O3 - δ, BaCe0.9Yb0.1O3 - δ, BaCe0.9Sm0.1O3 - δ and BaCe0.9Tb0.1O3 - δ was very small through the experimental conditions. This indicates that charge imbalance due to the trivalent dopants is compensated essentially by the oxygen vacancy formation. A large variation was found for δ of BaCe0.9Nd0.1O3 - δ by PO2 and temperature. This result indicates that the valence of the metal elements change under the experimental conditions. The X-ray absorption spectroscopy (XAS) measurement was carried out to examine the valence of the B-site elements of BaCe0.9Nd0.1O3 - δ. The samples of different δ were prepared. From the XANES spectra of Ce and Nd, no spectra change for Ce L3-edge was observed, while spectra change was observed for Nd L3-edge and L2-edge. This indicates that the valence of Ce stay unchanged, while the valence of Nd may be changed by the different δ conditions. The measured δ of BaCe0.9Nd0.1O3 - δ was analyzed by considering the valence change of neodymium. By considering the defect equilibrium among Nd′Ce, Nd×Ce, VO••, and OO×, the change of δ against PO2 was well explained by assuming the defect equilibrium frac(1, 2) O2 + VO• • + 2NdCe' = OO× + 2NdCe×.
KW - B-site doping
KW - BaCeO
KW - Oxygen nonstoichiometry
KW - Proton conductive perovskite-type oxides
KW - SOFC
KW - XAS
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U2 - 10.1016/j.ssi.2008.03.038
DO - 10.1016/j.ssi.2008.03.038
M3 - Article
AN - SCOPUS:44149128362
VL - 179
SP - 529
EP - 535
JO - Solid State Ionics
JF - Solid State Ionics
SN - 0167-2738
IS - 15-16
ER -