Rutile-to-anatase reverse phase transformation in nano titania with morphological changes in a hydrothermal approach

This report is on the reverse phase transformation of TiO2 from rutile to anatase in a highly alkaline medium at relatively low temperature (<250 degrees C) via a simple hydrothermal approach. A reverse phase transformation of this kind is highly beneficial from the application perspective due to the improved morphological, optical, and surface properties of the anatase phase. The morphology tuning is achieved by post-washing of the hydrothermal precipitate using dilute hydrochloric acid. Acid wash helps peeling off of the individual layers of the planar fragments obtained after hydrothermal treatment. Also, this study investigates the effect of pre-hydrothermal and hydrothermal temperatures on the specific surface area and porosity of the samples. X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller analyses are used to study structural, morphological, and surface properties, respectively.