Aqueous sol-gel synthesis, thermal analysis, characterization and electrical properties of V2O5 doped Bi2O3 system

Abstract

The aqueous sol-gel synthesis technique was successfully applied for the preparation of Bi–V–O tartrate gel precursors in the sol-gel process using tartaric acid as a ligand. By combining different characterization techniques, the influence of the complexing agent amount to both the elemental composition and surface morphology of the final ceramic was estimated. According to the decomposition mechanism of Bi–V–O tartrate gel precursors, it is clear that the coordination ability of tartaric acid significantly affects by its concentration in the water solution during the gelation process. Additionally, it was also showed that thermal analysis is a powerful method that enables the observation of several important processes, which are closely related to the decomposition of volatile compounds, phase transitions and stability of intermediates. Besides, it was demonstrated that X-ray diffraction and scanning electron microscopy strongly supplement the conclusions made from the results of thermal analysis. However, the content of elements in the gel precursor and ceramic powders measured by elemental analysis revealed that a molar ratio of bismuth and vanadium has a tendency to vary either by increasing the heat-treatment temperature or by decreasing the amount of tartaric acid. Finally, after the evaluation of obtained data the impedance analysis of 5Bi2O3·V2O5 ceramic was performed, which showed promising total conductivity values with 0.93 eV of activation energy in the range of investigated temperature.