Shape and size controlled synthesis of anatase nanocrystals with the assistance of ionic liquid.

We report an ionic liquid (IL) assisted hydrothermal method to synthesize anatase TiO(2) nanocrystals (NCs), in which TiCl(4) was used as precursor, 1-butyl-3-methylimidazolium chloride (bmim(+)Cl(-)) as IL, and F(-) or SO(4)(2-) ions as phase transformation inhibitor. The surfactant-like nature of IL was found to play a key role in controlling the crystallization process via controlling the aggregation manner of the NCs. The fine-tuning abilities of the operating parameters of the bmim(+)Cl(-)/TiCl(4)/H(2)O system facilitated the controlling over the shape and size of TiO(2) NCs. Phase-pure anatase monodisperse NCs with various shape and size were controllably obtained. Moreover, the aggregation manners of anatase NCs were also studied, and it was demonstrated that the high concentration of HF or H(2)SO(4) could result in aggregation of anatase NCs to form pseudo single crystals.