TiO₂ Phase Transformation Mechanisms at Atomic Scale under Heating and Electron Beam Irradiation

Titanium oxide (TiO2) has been extensively studied due to its low cost and promising applications, such as photo catalysis It has been reported that crystal phases play key role in determining crystal properties as well as particle size, morphology, and the exposed surface. For example, photocatalytic efficiency was optimized by mixed phases of anatase and rutile, such as degussa P-25 (~85 wt% anatase and ~15 wt% rutile) Therefore, understanding the structure evolution during TiO2 phase transformation and the relationships between phases is necessary for improving and controlling its properties. Although the phase transformation has been extensively studied, the mechanisms and their relationships to properties are still not fully understood especially at atomic scale. Anatase, brookite, and rutile are three common phases of TiO2. Here we investigated the atomic structure evolution of the three phases, as well as electron beam effects during in situ TEM heating experiments.