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Received: 16 January 2017/Accepted: 2 June 2017/Published online: 4 July 2017 © Shiraz University 2017
Abstract Recently, the GDC samples have been synthesized as promising materials for applying in solid oxide fuel cells. In the present research, two different kinds of gadolinium-doped ceria (GDC) nano-composites were prepared by a wetchemical method based on the sol-gel process and new precursors such as CeLH2, (pyda.H)2[(Ce(pydc)3].2CH3OH and (pyda.H)2[(Gd(pydc)3].2CH3OH, [pydc (2,6-Pyridinedicarboxylic acid), and GdLH2, pyda (2,6-diaminopyridine)]. The CeLH2 and GdLH2 coordination compounds have been prepared by high-energy ultrasound irradiation. The X-ray powder diffraction (XRD) results showed that the crystal lattice of the compounds (I), (II) was obtained cubic fluorite structures. The scanning electron microscope (SEM) analyses of the compounds (I), (II) indicated that the average grain sizes obtained about 20-30 and 50-70 nm, respectively. The results showed that using high intensity ultrasound can be utilized successfully for the synthesis of supramolecular coordination compounds.
Keywords Nanoparticles Gadolinium-doped ceria Ce(III) complex Gd(II) complex Solid oxide fuel cell
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1 Introduction
Solid oxide fuel cells have a great potential for being the cleanest, most efficient, significant environmental, and high electrical efficiency for the conversion of chemical to
electrical power generation (Neelima et al. 2015; Arabacı and Faruk Oksuzomer 2012). Yttria stabilized zirconia (YSZ) is the most commonly used for the SOFCs, which should be operated at 700-900 °C to ensure the sufficient ionic conductivity. However, at high operating temperatures, some destructive factors, such as thermal mismatch between material interfacial reactions at the electrodeelectrolyte and electrode-interconnector, may occur (Arabacı and Faruk Oksuzomer 2012). For this reason, the operating temperature should be reduced to intermediate temperatures (500-700 °C). The less expensive materials, such as steel, could be used in these secondary components (Ghourashia and Jadhav 2011). Ceria-based electrolytes have more oxygen vacancies which show a higher oxide ionic conductivity than YSZ at lower operating temperatures (500-800 °C) (Liu et al. 2013). The ionic section of the conductivity occurs by anion motion via vacancy mechanism. Comparing zirconia- and ceria-based systems' display, ceria has a higher ionic conductivity at intermediate temperature (600-800 °C). This is due to Ce4? radius (0.97 A) which is...