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| Hauptseite > Publikationsdatenbank > Quantifying the oxygen stoichiometry of Pr-doped ceria through X-ray diffraction |
| Hauptseite > Publikationsdatenbank > Quantifying the oxygen stoichiometry of Pr-doped ceria through X-ray diffraction |
| Conference Presentation (Other) | FZJ-2017-04341 |
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2017
Please use a persistent id in citations: http://hdl.handle.net/2128/14790
Abstract: Recent studies on Pr-doped CeO$_{2}$ (PCO) model electrodes suggest that the fast oxygen surface exchange coefficient and high ionic conductivity of PCO hold the potential for a high performance air electrode material for solid oxide fuel cells (SOFCs).[1] PCO behaves as a mixed ionic-electronic conductor (MIEC) in air at elevated temperature due to the reduction of Pr$^{4+}$ to Pr$^{3+}$ and a concomitant polaronic conductivity σpol. In this study, we characterize the reduction behavior of PCO with different Pr contents in air using high temperature X-ray diffraction (HT-XRD) and compare the results to TGA measurements. Rietveld analysis of the HT-XRD data reveals a temperature-dependent micro-strain in the PCO lattice that we associate with lattice disorder due to the different ionic radii of Pr$^{4+}$ and Pr$^{3+}$. This allows us to identify the precise temperature at which the polaronic conductivity σpol is highest for a given Pr-content. We discuss the effect of the temperature dependence of σpol for air electrodes in the context of conductivity and impedance measurements.1. Chen, D., S.R. Bishop, and H.L. Tuller, Praseodymium-cerium oxide thin film cathodes: Study of oxygen reduction reaction kinetics. Journal of Electroceramics, 2012. 28(1): p. 62-69.
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