Y-doped barium cerate protonic conductors with composition BaCe1 − xYxO3 − δ (x=0.02, 0.1, 0.2, 0.3) have been synthesized by sol–gel route, giving by X-ray diffraction tests a homogeneous crystalline phase. A commercial sample BaCe0.8Y0.2O3 − δ produced by combustion spray pyrolysis was also provided for comparison aim. The local structure around the cations was studied by X-ray absorption spectroscopy at the K-edges of Ba, Ce and Y. It is demonstrated that the insertion of yttrium in the site of cerium produces a remarkable local distortion of the dopant first-shell octahedral environment that affects also the next coordination shells by a static disorder increasing with dopant amount. For a dopant concentration estimated as x N 0.17, a poorly crystallized yttrium oxide phase that cannot be detected by X-ray diffraction is segregated. The static disorder around Y noticeably increases in the protonated samples and can be related to a preferential location of protons near the dopant.
F GIANNICI, A LONGO, F DEGANELLO, A BALERNA, A ARICO', MARTORANA A (2007). Local environment of Barium, Cerium and Yttrium in BaCe1-xYxO3-d ceramic protonic conductors. SOLID STATE IONICS, 178, 587-591 [10.1016/j.ssi.2007.01.015].
Local environment of Barium, Cerium and Yttrium in BaCe1-xYxO3-d ceramic protonic conductors
GIANNICI, Francesco;MARTORANA, Antonino
2007-01-01
Abstract
Y-doped barium cerate protonic conductors with composition BaCe1 − xYxO3 − δ (x=0.02, 0.1, 0.2, 0.3) have been synthesized by sol–gel route, giving by X-ray diffraction tests a homogeneous crystalline phase. A commercial sample BaCe0.8Y0.2O3 − δ produced by combustion spray pyrolysis was also provided for comparison aim. The local structure around the cations was studied by X-ray absorption spectroscopy at the K-edges of Ba, Ce and Y. It is demonstrated that the insertion of yttrium in the site of cerium produces a remarkable local distortion of the dopant first-shell octahedral environment that affects also the next coordination shells by a static disorder increasing with dopant amount. For a dopant concentration estimated as x N 0.17, a poorly crystallized yttrium oxide phase that cannot be detected by X-ray diffraction is segregated. The static disorder around Y noticeably increases in the protonated samples and can be related to a preferential location of protons near the dopant.File | Dimensione | Formato | |
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