TiO2 Nanocrystals : Synthesis & Enhanced Functionality

This book discusses phase selective and morphology controllable processing of titania (TiO2) nanocrystals and their enhanced functionality via doping for photo-catalytic, luminescent, and magnetic applications. Materials synthesis has been achieved by two "extreme" techniques: low temperature soft-chemical processing (typically <250°C) and high temperature RF (Radio frequency) thermal plasma processing (typically above 10,000°C). It is demonstrated that anatase, rutile and even the brookite polymorph of TiO2 can all be selectively synthesised in a phase-pure form via solution processing, sometimes even under near atmospheric conditions. Processing factors that govern phase structure and crystal morphology of the products are discussed. Detailed characterisations are given to the brookite phase with regard to its physio-chemical properties and its irreversible phase transition to rutile. It is also shown that quasi-equiaxed rutile nanocrystals, a morphological form rather difficult to make, can be obtained from Degussa P25 via a hydrothermal crystallisation/phase transformation process.