High crystallinity of TiO2 nanoparticles (NPs) with exposed {0 0 1} facets was prepared by an alcohothermal method without the addition of any specific organic reagents, in which titanium isopropoxide was used as the titania precursor, water and ethanol (0.6/90-5/90, v/v) as the reaction medium. The X-ray powder diffraction (XRD) and transmission electron microscope (TEM) measurements showed that water played an important role in conducting the size, shape, crystallinity and microstructure of TiO2 NPs. The photoluminescence spectroscopy and photocurrent measurements indicated that enhanced crystallinity could hinder effectively the recombination and promote significantly the separation of electron-hole pairs in TiO2 NPs. These will contribute to the enhancement of photocatalytic performance. Methyl orange photodegradation under UV light confirmed that high crystallinity of TiO2 NPs did exhibit a high photocatalytic activity due to the effective separation of photoinduced charges and exposure of highly reactive {0 0 1} facets. (C) 2014 Elsevier Ltd. All rights reserved.