Study of Phase Transformation and Microstructure of Solgel Prepared-Alcohol Washed Nanostructured Titania

Abstract

Undoped titanium dioxide was prepared by the means of sol gel technique. Washing of the sol (i.e. either by water or by alcohol) was taken as initial varying input. Powder was synthesized by the hydrolysis of water with the Titanium Isopropoxide in the presence of 2-propanol. As-prepared samples were heat treated at different temperatures ranging from 450° C to 750° C, with the motive to study the effect of different washing treatment on the anatase to rutile phase transformation temperature and the microstructure. Samples were characterized by X-ray diffraction technique (XRD), TGA / DSC, UV-Vis spectroscopy (DRS) and FE-SEM. For water washed samples, anatase to rutile transformation temperature was obtained as 693°C, whereas for alcohol rinsed samples this temperature comes out as 777 °C. Apart from this, micrographs obtained from FE-SEM showed complete densification and exaggerated particle growth in the water washed samples, on the other hand alcohol washed samples showed some small amount of porosity with relatively lower particle size. This behavior of alcohol washed samples had been attributed to ‘critical-particle- nuclei-theory’ as discussed in detail here in this report.