Synthesis by the polymeric precursor technique of Bi2Co0.1V0.9O5.35 and electrical properties dependence on the crystallite size

a-Bi2VO5.5 and gamma-Bi2Co0.1V0.9O5.35 specimens with different crystallite sizes have been synthesised by the citrate technique. The thermal evolution of the material was followed by powder X-ray diffraction (XRD) and differential thermal analysis (DTA). The synthesis of these materials is obtained via the formation of the intermediate BiVO4 phase. Complete disappearance of BiVO4 and completion of the reaction can only be achieved after the sample is annealed at 750degreesC, leading to highly pure Bi2VO5.5 in the orthorhombic alpha-phase and Bi2Co0.1V0.9O5.35 in the tetragonal gamma-phase. The effect of the crystallite size on the electrical conductivity of Bi2Co0.1V0.9O5.35 was investigated by impedance spectroscopy. The results indicate that the conductivity is significantly higher for materials with smaller crystallite size. (C) 2003 Elsevier SAS. All rights reserved.