Gas sensing properties of graphene-WO3 composites prepared by hydrothermal method

Graphene-WO3 composites mixed with different amounts of graphene (0, 0.1, 0.5, 1 and 3 wt%) were prepared by hydrothermal method at 180 degrees C for 24 h. The as-prepared graphite oxide, graphene and graphene-WO3 composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR) and Raman spectroscopy, respectively. The effect of the amount of graphene in the composites on the gas-sensing responses and the gas-sensing selectivity of the materials was investigated. The experimental results revealed that the sensor based on 0.1 wt% graphene-WO3 composite exhibited high response and good selectivity to acetaldehyde vapor at 100 degrees C, the optimum operating temperature of this sensor to 1000 ppm acetaldehyde vapor decreased from 180 degrees C to 100 degrees C comparing with that of pure WO3. The response time and the recovery time for 100 ppm acetaldehyde vapor were 250 s and 225 s, respectively. (C) 2014 Elsevier B.V. All rights reserved.