Hydrothermal synthesis of anatase nanoleaves and size dependence of anatase–rutile transformation upon heating

Amorphous TiO2 obtained by adding TiCl4 to an alkaline medium crystallizes slowly and upon 3 years ageing transforms to nanosized anatase containing an admixture of brookite. The hydrothermal treatment of this sample in solutions of lithium hydroxide leads to anatase nanoleaves, and the more concentrated LiOH solution, the greater the nanoleaves and the smaller their specific surface area. The thermal treatment of nanoleaves leads to the bulk rutile, and the greater the specific surface area of anatase nanoleaves, the lower the anatase–rutile transition temperature. This is in line with conclusions based on the thermodynamic stability of nanosized anatase over the bulk rutile.