Molybdenum disulfide (MoS2) nanosheets have received significant attention recently due to the potential applications for exciting physics and technology. Here we show that MoS2 nanosheets can be prepared by a facile hydrothermal method. The study of the properties of the MoS2 nanosheets prepared at different conditions suggests that the mole ratio of precursors and hydrothermal time significantly influences the purity, crystalline quality and thermal stability of MoS2. X-ray diffraction, Raman spectra and transmission electron microscopy results indicate that bilayer MoS2 can be grown under an optimized mole ratio of 2:1 of S:Mo at 180 degrees C for 50 h. Moreover, such ultrathin nanosheets exhibit a prominent photoluminescence and possess high methyl orange adsorption capacity due to the large surface area, which can be potentially used in photodevice and photochemical catalyst. (C) 2014 Elsevier Ltd. All rights reserved.