Spherical shaped anatase nanoparticles (empty set 5nm) have been synthesized in the ionic liquid 1-(3-hydroxypropyl)-3-methylimidazolium-bis(trifluoromethanesulfonyl)ami de from titanium tetraisopropoxide by ultrasound assisted synthesis under ambient conditions. XRD EDX TEM XPS Raman, UV-vis, PL and BET measurements have been employed for characterization of the nanostructure of as-prepared TiO2. XRD and Raman measurements both show that the obtained material is crystalline with anatase structure. The morphology of TiO2 nanoparticles was characterized by transmission electron microscopy (TEM). The bandgap of the TiO2 nanocrystals estimated from XRD and UV-vis measurements is about 3.3 eV. The surface area of a typical sample is 177 m(2) g(-1). The synthesized anatase nanocrystals show good photocatalytic activity in the degradation of methylorange. (C) 2009 Elsevier B.V. All rights reserved.