Structural and electrochemical characterization of SnO2 and SnO2–Co3O4 mixed oxides synthesized by Pechini method

Abstract

Tin oxide SnO2 and SnO2–Co3O4 were synthesized by the Pechini method in presence of stannous and cobalt precursors, citric acid and ethylene glycol. The X-ray diffraction study revealed that the SnO2 prepared exhibited tetragonal crystal structure and the binary system SnO2–Co3O4 showed a biphasic behavior with a tetragonal structure and the cubic structure of Co3O4. The thermal stability of materials was characterized by thermogravimetric and differential thermal analysis and the morphology by scanning electron microscope. It was found that the presence of octahedral crystals of the mixed oxide increased the surface area with a maximum centered around 15 mol% of Co3O4. The presence of increasing ratio of Co3O4 in the binary system did not produce the expected increase of specific capacitance but the cycling behavior at the electrochemical test of galvanostatic charge–discharge for 15 mol% of Co3O4 showed 98 % of the initial capacitance after 1000 cycles making this material promising as an electrochemical capacitor with structural stability.