Structural and dielectric behaviour analysis of TiO 2 addition on the ceramic matrix BiVO 4

In this work, the dielectric and electric properties of the ceramic matrix BiVO4 (BVO) and the effects of the addition of TiO2 were analysed by impedance spectroscopy (IS). The BVO phase was calcined at 773 K and used to prepare the composite ceramic which the titanium oxide was added (15, 30 and 60 wt% TiO2), molded in pellet shape and sintered at 1073 K. These samples were characterized by X-ray diffraction (XRD). The thermo-activated charge transfer process for the ceramics BVO with the respective additions was observed and the electric results were compared with the electric response of equivalent circuit composed of three associations in parallel with R-CPE and represented by the Nyquist diagram. At room temperature and in the frequency range of 1 Hz, the samples presented high relative permittivity, er = 26k to approximately 35k, and a dielectric loss at the order of 10−2 at 1 MHz. The composites presented negative and positive values of the temperature coefficient of capacitance (TCC) along TiO2 composition. Through IS coupled with temperature variation, the activation energies were measured; the values showed decrease with increasing withTiO2 concentration.