Search results for "Characterization techniques"
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The local structure of SOFC materials investigated by X-Ray absorption spectroscopy
2016
This chapter is devoted to the analysis of the local atomic structure of solid oxide fuel cell (SOFC) electrolyte and electrode materials. Among the experimental techniques able to provide information about the local structure of materials, the X-ray absorption spectroscopy has the peculiarity of element selectivity, allowing to investigate the chemical environment of specific atoms embedded in a matrix. Solid oxide electrolytes allow the conduction of ionic charge carriers between the electrodes of a SOFC device; the mechanism of ion conduction depends on the type of carrier, and it is finely tuned-or even only possible-if the solid matrix is suitably tailored by insertion of doping specie…
Effect of Pre-Reduction on the Properties and the Catalytic Activity of Pd/Carbon Catalysts: A Comparison with Pd/Al2O3
2013
The effect of pre-reduction in solution with chemical reagents on the catalytic performance and catalyst properties of Pd/carbon catalysts was systematically investigated with a multitechnique approach. The results are critically discussed in comparison to those recently obtained on analogous Pd/alumina catalysts. It was proved that the Pd phase on the carbon surface is characterized by a high mobility, opposite to what occurs on alumina. As a result, the Pd particles on carbon aggregate together during pre-reduction, with a consequent decrease in available metal surface. Pd particles remain aggregated also in reaction conditions; the decreased Pd dispersion negatively affects the catalyst …