Effect pH Variation of Powder Materials of the Composite Oxide Ba_(x)Sr_(1-x)Co_(y)Fe_(1-y)O_3-dObtained by Citrate-EDTA Method

Abstract

The Ba(x)Sr(1-x)Co(y)Fe(1-y)O3-d (BSCF) powder, used with cathode in intermediated temperature solid oxide fuel cells (ITSOFCs), has been prepared by Citrate-EDTA method and calcined at 900°C for 5h. Among the parameters to be checked in a liquid phase reaction, the pH of precursor solution is very important to control the disposal of organic, crystal structure and powders morphology. In this work, precursor solution pH has been variegated 2, 4, 6 and 8. The thermal decomposition has been observed in infrared, two absorption peaks are observed at 1436 and 860 cm-1, after calcination, corresponding to the presence of CO32-, in the samples with pH 2, 6 and 8. The single phase of Perovskite crystalline structure is seen only in the synthesis at pH 4 and 6, verified by X-ray diffraction (XRD). Morphological analysis, by scanning electron microscope (SEM), shows the powder is agglomerated and has similar trend independent of precursor solution pH.

Ba₀.₅Sr₀.₅Co₀.₈Fe₀.₂-SDC Carbonate Composite Cathode for Low-Temperature SOFCs

“…It is generally believed that reduction of operation at low temperature (LT) (400 to 600 ºC) is a possible solution for the commercialization of SOFCs. However, working at LT limits the electrochemical performance of BSCF [2,3]. To overcome this limitation, an electrolyte material must be added.…”