SnO2 nanosheets were synthesized by a hydrothermal method at 200 degrees C using stannic chloride hydrate and sodium hydroxide as starting materials. The as-synthesized nanoparticles and nanosheets are characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The gas response, selectivity, and response speed were optimized by varying the morphology of the sensing materials and operation temperature. Most importantly, the SnO2 nanosheets sensor exhibits high response, low detection limit and fast response to ethanol. The gas response of the SnO2 nanosheets to 100 ppm ethanol was 39.6 at 300 degrees C, which was 3.6 and 6.1 times higher than that of the nanospheres-like and the nanoparticles, respectively. Response and recovery times were 1 and 9 s when the sensor was exposed to 20 ppm ethanol at an operating temperature of 300 degrees C. (C) 2012 Elsevier Ltd. All rights reserved.