Preparing single-phase nanocrystalline anatase from amorphous titania with particle sizes tailored by temperature

Series of samples of nanoparticles with discrete sizes are needed for studies of the particle size dependence of materials properties. In this study, phase relations during heat treatment of initially amorphous titania were determined. Heating amorphous titania in air at specific temperatures for specific lengths of time resulted in single-phase nanocrystalline anatase powders with average particle sizes between 7 and 50 nm. An important pathway for anatase growth involved nanocrystal reorientation within particle aggregates. Large quantities of single phase solids can be produced via this method.