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
N1 - Funding Information:
Author thanks Mr. David Tuerp of RWTH Aachen University, for his help in carrying out the experiments. This work was supported by the 21st Century COE Program “International COE of Flow Dynamics and the Grant-in-aid for Scientific Research on Priority Area, Nanoionics (439)” by the Ministry of Education, Culture, Sports, Science, and Technology of Japan.
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 -