Synthesis of square-like anatase TiO2 nanocrystals based on TiOF2 quantum dots

In this study, a simple hydrothermal route was developed for the synthesis of the square-like anatase TiO2 nanocrystals starting from TiOA and NH4F raw materials. The synthesized nanocrystals exhibited a high percentage 64% of exposed {0 0 1} facets and highly crystalline. The size of square-like nanocrystals was found to be ca. 50–80 nm and their thickness was 10–20 nm. It was found that the intermediate TiOF2 QDs formed before the hydrothermal reaction played a key role for the formation of square-like anatase TiO2 nanocrystals. Based on a series of experimental results, a possible mechanism for the formation of square-like anatase TiO2 nanocrystals with a highly exposed {0 0 1} facet was proposed.