Crystallization Process of TiO2 Nanoparticles in an Acidic Solution

Hydrolysis of titanium tetraisopropoxide followed by condensation at 30 °C yields amorphous TiO2. Addition of nitric acid for peptization greatly accelerates the rate of amorphous to anatase conversion, resulting in an anatase with locally imperfect atomic structure. Further conversion to rutile in acidic solution has been observed and a plausible phase transformation process has been postulated.