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Influence of annealing on yttrium dopant distribution in ceria-based nanoparticlesкнига
- Авторы: Shih S.J., Li G., Huang C.K., Borisenko K.B.
- Год издания: 2011
- Место издания: Nova Science Publishers, Inc
- Аннотация: Yttrium is one of the most widely used dopants (e.g. in yttrium-doped ceria (YDC) and yttriastabilized zirconia) for improving performance of solid electrolytes utilized in solid-oxide fuel cells (SOFC). It is well-established that oxygen ion conductivity is a function of yttrium concentration in the electrolytes and detailed knowledge about factors influencing such concentration distribution is important. In this study, we examine the change in distribution of yttrium concentration after annealing in YDC particles. The geometry and morphology of YDC particles, synthesized by spray pyrolysis, were characterized by transmission electron microscopy (TEM), and the distribution of yttrium was investigated by X-ray energydispersive spectroscopy (XEDS) considering electron interaction volume and geometry of the particle in the XEDS profile analysis. In addition, relative concentrations of Ce (III) ions, which are thought to be proportional to the concentrations of oxygen vacancies in the YDC particles, were examined using X-ray photoelectron spectroscopy (XPS) to correlate with yttrium concentration distributions. It was found that in the as-prepared hollow spherical particles the concentration of the yttrium increases linearly from the inner surface towards the outer surface. After annealing the distribution of yttrium becomes non-linear with the dopant migrating to the inner and outer surfaces of the particle. The concentration of Ce(III) ions decreases upon annealing, following the change in the dopant concentration gradient, mostly due to increase in the size of the crystallites in the particles. © 2011 by Nova Science Publishers, Inc. All rights reserved.
- Добавил в систему: Borisenko Konstantin B.