Low temperature nanostructured zinc titanate by an aqueous particulate sol-gel route: Optimisation of heat treatment condition based on Zn:Ti molar ratio

Nanocrystalline zinc titanate (ZnTiO(3)) thin films and powders with purity of 94% were produced at the low sintering temperature of 500 degrees C and the short sintering time of 1 h by a straightforward aqueous particulate sol-gel route. The effect of Zn:Ti molar ratio was studied on the crystallisation behaviour of zinc titanates. The prepared sols showed a narrow particle size distribution in the range 17-19 nm. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders contained mixtures of the rhombohedral-ZnTiO(3), cubic-ZnO, cubic-Zn(2)TiO(4) phases, as well as the anatase-TiO(2) and the rutile-TiO(2) depending on the sintering temperature and Zn:Ti molar ratio. Moreover, it was found that Zn:Ti molar ratio and sintering temperature influence the preferable orientation growth of the zinc titanate, being on (2 1 1) planes for molar ratios of Zn:Ti = 25:75 and 50:50 and on (1 (1) over bar 0) planes for molar ratio of Zn:Ti = 75:25 at sintering temperature of 600 degrees C. Transmission electron microscope (TEM) images showed that the average crystallite size of the powders annealed at 400 degrees C was around 2 nm and a gradual increase occurred up to 8 nm by heat treatment at 1000 degrees C. The activation energy for crystal growth of nanocrystalline ZnTiO(3) calculated in the range 07.86-14.79 kJ/mol. Field emission scanning electron microscope (FE-SEM) analysis revealed that the deposited thin films had mesoporous and nanocrystalline structure with the average grain size of 19-23 nm at 600 degrees C and 34-39 nm at 800 degrees C depending upon the Zn:Ti molar ratio. (C) 2009 Elsevier Ltd. All rights reserved.