Synthesis and photocatalysis study of brookite phase titanium dioxide nanoparticles

Titanium dioxide is mainly being used as a white pigment in the paint industry. It is also being used as a delustrant in fibers. Nanofabrication of TiO2 makes it useful in variety of other important applications like photocatalysis, self-cleaning coatings, fog proof glass and water purifier. This is one of the reasons for large amount of research being done in synthesis of TiO2 and its applications in various fields. Titanium dioxide, TiO2 or titania mainly exists in three crystalline polymorphs namely; anatase, rutile and brookite. Anatase and rutile phases have been explored thoroughly. Comparatively less work is done on the synthesis and applications of brookite phase TiO2 nanoparticles.; The main goal of this research work is to synthesize brookite phase TiO 2 nanoparticles, characterize these particles by various techniques, estimate the photoactivity of the powder and apply the powder as a scratch resistant coatings. The work was divided into three parts.; Chapter 2 deals with the synthesis of brookite phase TiO2 particles by ambient condition sol (ACS) process. The brookite particles formed were checked for phase purity and calculation of crystallite size by X-ray diffraction (XRD), phase morphology by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and thermal analysis. Calcination of the particles showed complete phase change from brookite phase to rutile by 600°C.; Chapter 3 consists of investigation of the photoactivity of brookite phase TiO2 nanoparticles. UV-Vis absorption spectra for non-calcined and calcined brookite nanoparticles showed absorption characteristics in the visible region. Decrease in degradation rate of methyl orange was observed with increase in calcination temperature and decrease in the surface area of the powders. Comparison of three phases determined the brookite phase to have fastest degradation rate after particular time of UV exposure.; Chapter 4 involves the basic application of these nanoparticles as scratch resistant coatings using a binder material. A new binder material was developed. The coatings had good adhesion to the glass substrate used. A simple scratch test was done to determine the scratch resistance of the binder and the coatings. The brookite phase TiO2 nanoparticles had better adhesion and scratch resistance compared to the Degussa P25 powder (approximately 85% anatase and 15% rutile).