Preparation of Sr2Fe1–xScxMoO6–δ nanopowders and its electrical conductivity

Double-perovskite Sr2Fe1–xScxMoO6–δ (x=0, 0.05, 0.1, 0.2, 0.3, 0.4) powders applied to the cathode of solid oxide electrolysis cells were synthesized by the sol-gel citrate combustion method. Initial powders were calcined at different temperatures under different atmosphere (air, H2(4 vol.%)/Ar), and the effects of the preparation process on the structure and the morphology of the powders were investigated by thermal analysis (TG/DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and surface area analysis. The electric conductivity of the materials was measured by electrochemical work station using wafers prepared by dry pressing. It was found that the formation of perovskite structure was related to the content of Sc and combustion improver (NH4NO3), pH value, calcining temperature and atmosphere. A single perovskite phase of Sr2Fe1–xScxMoO6–δ could be formed after 3 h calcining in reducing atmosphere of H2 (4 vol.%)/Ar at 1100 °C. The electrical property indicated that, this material had a potential to be used in medium/high temperature solid oxide fuel cells or electrolysis cells.