5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Structural And Electrical Characterizations Of Double Perovskite System Sr2comoo6−δ

A widespread research work on Mo based double perovskite systems have been reported as potential application for electrode materials of solid oxide fuel cell [1]. Mo based double perovskites studied in form of B-site ordered double perovskite materials, with general formula A2BB″O6 structured by alkaline earth element (A = Sr, Ca, Ba) and heterovalent transition metals (B = Fe, Co, Ni, Cr, etc. and B″ = Mo, W, etc.), are raising a significant interest as potential mixed ionic-electronic conductors in the temperature range of 500-800 °C [2, 3]. Such systems reveal higher electrical conductivity, particularly those assigned in form of Sr2MMoO6 (M = Mg, Mn, Fe, Co, Ni, Zn etc.) which were studied in different environments (air/H2/H2-Ar/CH4) at intermediate temperature [4]. Among them, Sr2CoMoO6-δ system is a potential candidate for anode material in SOFC due to its good electronic conductivity [5]. Therefore, Sr2CoMoO6-δ system has been studied to discover more applications of structural and electrical properties. The double perovskite system Sr2CoMoO6−δ (SCM) was synthesized by the citrate-nitrate auto-combustion synthesis route. Thermal studies were carried out by thermal gravimetry analysis. Phase constitution was observed by powder X-ray diffraction (XRD). A minor phase of SrMoO4 (s.g. I41/a) was identified as secondary phase using JCPDS card no. 85-0586. Rietveld refinement showed the major phase to exist in tetragonal form with space group I4/m and also observed % of volume fraction of SrMoO4. Micro-structural investigations revealed the formation of uniform grains. The average grain size of compositions SCM was calculated by linear intercept method was found to be ⁓3.1 μm. The electrical conductivity studied by impedance spectroscopy in the temperature range 200-600˚C, was found to follow a thermally activated process The electrical conductivity of the system was discussed in terms of identified impurity phases and charge density [[Mo_(Mo^(6+))^(5+)]^ ].
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