Specificity of the Local Structure of Nanocrystalline Doped Ceria Solid Electrolytes
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Specificity of the Local Structure of Nanocrystalline Doped Ceria Solid Electrolytes Vladislav A. Sadykov, Yulia V. Frolova, Vladimir V. Kriventsov, Dmitrii I. Kochubei, Ella M. Moroz, Dmitrii A. Zyuzin, Yulia V. Potapova, Vitalii S. Muzykantov, Vladimir I. Zaikovskii, Elena B. Burgina, Holger Borchert, Sergei Trukhan, Vyacheslav P. Ivanov, Stylianos Neophytides1, Erhard Kemnitz2, Kerstin Scheurell2 Boreskov Institute of Catalysis SB RAS, Lavrentieva, 5, 630090, Novosibirsk, Russia 1 Institute of High Temperature Processes & Chemical Engineering, GR-26500, Patras, Greece 2 Institute of Chemistry, Humboldt University, Brook-Taylor-Str. 2, D-12489 Berlin, Germany ABSTRACT This work presents results of studies of the structural features of nanocrystalline doped Ce1xMexO2-y samples (Me = Sm, Bi, Gd; x = 0-0.5) prepared via the polymerised precursor (Pechini) route by using a combination of diffraction (XRD, TEM, WAXS on SR) and spectroscopic (EXAFS, Raman, FTIRS of lattice modes, XPS, SIMS) methods. INTRODUCTION Nanocrystalline ceria doped with low-valence cations is known to possess a high oxygen–ion conductivity due to the presence of anion vacancies [1]. This makes ceria-based systems attractive for various applications like intermediate-temperature solid oxide fuel cells [2], electrochemical oxygen pumps and components of oxygen-conducting membranes [3], catalytic systems for partial oxidation of methane or other hydrocarbons to syngas [4], etc. These applications are due to the possibility of easy sintering into mechanically strong dense ceramics as well as specific defect/transport properties associated with high surface/grain boundary areas. However, only little is known about the specificity of the real/defect structure of nanocrystalline doped ceria due to difficulties of its characterization by traditional diffraction methods. The aim of this paper is the study of the real/defect structure of ceria doped with Bi, Sm and Gd cations by using more sophisticated diffraction and spectroscopic methods. EXPERIMENTAL DETAILS Dispersed samples of ceria-based solid solutions with Sm, Bi or Gd content in the range of 10–50 at.% were prepared by a polymerized complex precursor route as in [5, 6] and calcined at 500 oC. Samples were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Wide-Angle X-ray Scattering (WAXS) on synchrotron radiation (SR) as well as by spectroscopic methods such as Extended X-ray Absorption Fine Structure Spectroscopy (EXAFS), Raman, Fourier –transform Spectroscopy of Lattice Modes (FTIRS), X-ray Photoelectron Spectroscopy (XPS), and Secondary Ions Mass-Spectrometry (SIMS). XRD experiments were performed using an URD-6 diffractometer with monochromatized Cu Kα radiation, and a JEOL JEM-2010 transmission electron microscope operating at 200kV was used for TEM studies [6]. The EXAFS spectra of the Ce-L3, Sm-L3, Gd-L3 and Bi-L3 edges were obtained at the EXAFS Station of the Siberian Synchrotron Radiation Center. The storage
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ring VEPP-3 with an electron
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