Electrical conductivity characterization of Bi4V2O11 doped with sulfur prepared by hydrothermal process
Résumé
Bi4V2−xSxO11+δ (BiSVOx) compounds (0.0 ≤ x ≤ 0.5), prepared by the hydrothermal method, were characterized by various techniques, such as X-ray diffraction (XRD), Raman spectroscopy, IR spectroscopy, thermo-gravimetric analysis (DTA/TGA), and scanning electron microscopy (SEM). It is confirmed that this synthesis method has an important impact, especially on the crystallinity and morphology of these materials. The BiSVOx phases obtained crystallize in the tetragonal γ-Bi4V2O11 structure type. Spherical grains made of nanoparticles characterize the morphology of the powders resulting from the synthesis. The stability of the BiSVOx samples has been studied by DTA/TGA analysis performed up to 1000 °C. Electrochemical impedance spectroscopy was used to measure the electrical conductivity of these compounds. Contrary to what is generally observed in BiMeVOx, The conductivity increases with the substitution rate. The highest conductivity values were obtained in the case of the sample with composition x = 0.4.