Synthesis of nanosized TiO2 powders via a hydrothermal microemulsion process

A microemulsion process combined with hydrothermal techniques has been developed for synthesizing anatase-type titania in this study. Nanosized TiO2 powders were successfully prepared by employing this hydrothermal microemulsion process. The particle and crystallite sizes of the formed TiO2 powders significantly depended on the pH value of microemulsion solutions. Low pH microemulsion solutions resulted in the formation of spherical particles, whereas neutral solutions gave rise to rod-like particles. The mechanisms of nucleation and crystal growth were influenced by the acidity of the solutions. The rod-like particles had much larger specific surface area than the spherical ones. The large surface area of the rod-like particles resulted in significantly enhanced photocatalytic activity.