Structural and optical properties of zinc titanates synthesized by precipitation method

Synthesis of zinc titanates was carried out using a simple precipitation method followed by calcination at different temperatures to obtain different phases of the material. The phase transition characteristics, presence of functional groups, structural aspects and optical bandgaps with respect to calcination temperature were studied by thermal analysis, EDAX, FT-IR, powder XRD, Raman and UV-Vis spectroscopy respectively. The compound on heat treatment at 100 degrees C for 24 h showed broadened peaks in XRD. With increasing temperature of calcination, the compound appeared to turn to crystalline phase and cubic ZnTiO3 phase was observed at 600 degrees C. Partial phase transformation of cubic phase ZnTiO3 into hexagonal ilmenite type ZnTiO3 was observed in the temperature range 700 degrees C to 900 degrees C. At 1000 degrees C both cubic and hexagonal ilmenite phases decomposed into cubic phase Zn2TiO4 and rutile TiO2. FT-IR showed M-O bonds in the range of 400 cm(-1) to 700 cm(-1). Raman spectra of cubic defect spinel ZnTiO3 and cubic inverse spinel Zn2TiO4 were found to be similar. The optical bandgap calculated using diffuse reflectance spectra was found to be in the range of 3.59 to 3.84 eV depending on calcination temperature.