Abstract
Ultrafast formation of ZnO mesocrystals was achieved with a facile, green, Tris-assisted, room temperature ionic liquid based antisolvent process. A deep eutectic solvent, formed by simply mixing and heating urea and choline chloride at 70 °C, served as the solvent for ZnO, whereas Tris-containing de-ionized water acted as the anti-solvent to trigger the ultrafast formation of ZnO mesocrystals at 70 °C. The product mesocrystals were mesoporous and near-single-crystalline with high specific surface areas, showing excellent photocatalytic activities toward photodegradation of methylene blue, comparable to that of a commercial photocatalyst, P-25 TiO 2 , which is rarely achieved for pristine ZnO. The present approach is a general one and can be readily extended to production of mesocrystals of other functional metal oxides. © 2011 The Royal Society of Chemistry.