Synthesis and Crystal Growth Mechanism of Titanium Dioxide Nanorods

Highly crystalline and monodisperse anatase TiO2 nanorods were synthesized successfully via an improved solvothermal method. The shape evolution of TiO2 nanorod was investigated by adjusting the reaction parameters, such as reaction duration and temperature. The phase structures, morphologies, and sizes of as-prepared TiO2 nanoparticles were investigated in detail by XRD, TEM, and HRTEM. The photocatalytic properties of the product were measured by decomposition of methylene blue under full spectrum light irradiation. When Ostwald Ripening is dominant, the TiO2 nanorods grow along the < 001 > crystallographic direction. When Ostwald Ripening is depressed at lower temperature, Oriented Attachment occurs. And primary nanoparticles join together by sharing a common (001) facet. The driving force of shape evolution and crystal growth of TiO2 nanocrystals is reducing the high surface free energy. Compared with P25, the as-prepared TiO2 nanorods exhibit a superior photocatalytic activity, which is attributed to the high crystallinity.