Synthesis Temperature Dependent Morphological Evolution in Zinc Titanate Heteronanostructures and Their Application in Environmental Remediation

摘要

The synthesis of Zn-Ti glycolates at different temperatures (RT to 200 8C) with different morphologies which convert to zinc titanate heteronanostructures after calcination (500/700 8C) has been reported. The effect of synthesis temperature on morphology, optical properties and photocatalytic activity of the heteronanostructures has been investigated. X-ray diffrac- tion studies indicate that after calcination, cubic ZnTiO3 is formed from the Zn-Ti glycolates synthesized at lower temper- atures (100 8C) while Zn2TiO4 is formed at higher temper- atures (>100 8C). Electron microscopy studies show that the Zn-Ti glycolates synthesized at lower temperatures (100 8C) and the corresponding zinc titanates exhibit rod-like morphol- ogy. The Zn-Ti glycolate synthesized at 150 8C and the corresponding zinc titanate possess mixture of rod and spherical morphology. The Zn-Ti glycolates synthesized at 180 and 200 8C and the zinc titanates exhibit spherical morphology. The rods and spheres were found to be formed in turn by assembly of nanoparticles. Diffuse reflectance spectroscopic studies show that the band gap of zinc titanates (3.2 eV to 3.75 eV) depends on synthesis temperature of Zn-Ti glycolates and also the calcination temperature. The zinc titanate heterona- nostructures were explored as catalysts for the photodegrada- tion of rhodamine B and crystal violet in aqueous solutions in the presence of sunlight and the zinc titanate spheres exhibit the best catalytic activity.