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Nanocomposites are a cohesive class of materials, which have many technological applications due to their excellent properties, realizable within the range of 1–100 nm sizes. Ferrite nanocomposites have been used as the potential candidate materials for photocatalytic and electrocatalytic anodes for oxidation of organic compounds like phenol, anodes for lithium batteries, inert anode for aluminium electrolysis, etc. Recently these are envisaged as an eco-friendly substitute for carbonaceous materials in electrochemical applications. In the present study the CuFe 2 O 4 /SnO 2 nanocomposites have been prepared by a novel combustion method. The TEM figure confirms the nanocrystalline nature of the as-synthesized product. XRD spectra show the well-defined crystalline nature and a phase transition of tetragonal to cubic on increased SnO 2 substitution. The band gap values calculated from the UV-Vis spectra are in the vicinity of semiconducting range. The maximum a.c. electrical conductivity of 1.75×10 -3 S · cm -1 was obtained for CuFe 2 O 4 /5% SnO 2 composition. The impedance spectrum also confirms the semiconducting behavior of the materials. [ABSTRACT FROM AUTHOR]

The non-stoichiometric perovskite-type oxide SrFeO3−δ was prepared by Co-precipitation method using metal nitrate salts as cation precursors and NaOH solution as the precipitating agent. From the thermogravimetric analysis, the strontium orthoferrite phase formation was found to be complete at 550 °C. The XRD spectra showed the synthesized compound to be of orthorhombic structure. The FTIR spectra confirm the characteristic peaks of SrFeO3−δ stretching and bending vibrations. The submicron size of the synthesized compound was showed by scanning electron microscope. The physical properties such as density, porosity and hardness were also carried out. The DC electrical conductivity measurements gave the maximum value of 84 S cm−1 for the 1000 °C sintered sample. The electrochemical behavior of the 800 and 1000 °C sintered SrFeO3−δ electrode was performed in alkaline KOH solution by potentiostatic polarization and electrochemical impedance spectroscopy. [Copyright &y& Elsevier]