Surfactant-free Synthesis of Anatase TiO2 Nanorods in an Aqueous Peroxotitanate Solution

We report for the first time the formation of spindle-type, monodispersed anatase nanorods from a peroxotitanate solution without the use of organics (such as surfactants). The formation process is highly dependent upon soaking time, solution pH, and concentration, undergoing both morphology and phase transformation during growth. We found that the mechanism of formation is similar to that of a gel−sol process: the initial amorphous gel is converted to anatase titania rods using ammonia as a shape controller. Both previous and current studies on the synthesis of TiO 2 from peroxotitanate solution show that, under appropriate conditions, the peroxotitanate solution can be used to produce large quantities of TiO 2 nanoparticles of controlled polymorph type, morphology, and size.