Concentration-driven phase control for low temperature synthesis of phase-pure anatase and rutile titanium oxide.

It is highly desirable to develop controlled synthetic methods at low temperature (<100°C) for defined phases of titanium oxide nanoparticle. We present here a simple low temperature approach which is based on the peroxide route. This approach allows the preparation of phase-pure rutile and anatase without the use of any additives or surfactants or external acids. The formation of crystalline phases is found to be dependent on reaction temperature and highly dependent on concentration. Phase-pure rutile is obtained in two concentration zones while phase-pure anatase is obtained in one concentration zone. The relationship between phases and reaction conditions (concentration and temperature) fits well with the nucleation diffusion rate model.