Electron microscopic study on high-pressure induceddeformation of nano-TiO2 br

The high-pressure a-PbO2 phase of TiO2 has suitable band gap and photocatalytic capability in the visiblelight range, which is an environmentally friendly and efficient photocatalytic material. In this work, a-PbO2phase of TiO2 is obtained by the pressure-relief treatment of anatase nanospheres through using diamond anvilcell, and transmission electron microscope (TEM) observation shows the obvious deformation of TiO2nanospheres. High-esolution TEM shows that there are a large number of stacking faults along the [100]direction and deformation twins in the grain. Specifically, the deformation twin band with lens lamellarstructure is formed in the submicron grain. The fan-shaped multiple deformation twins are formed in thenanocrystalline grains. This study shows that anatase TiO2 can be deformed under high pressure, and its micromechanism of deformation is similar to metal's, mainly including deformation twins and stacking fault slip.There is obvious size effect in the formation of deformation twins. These results provide a new breakthroughpoint for the study of the size effect of high-pressure phase transformation of TiO2, and also point out anexperimental direction for preparing the twin high-pressure a-PbO2 phase.