Solvothermally synthesized tungsten oxide nanowires/nanorods for NO2 gas sensor applications

One-dimensional nanorods or nanowires of W18O49 were synthesized by solvothermal method at 200 degrees C with tungsten hexachloride (WCl6) as precursor and cyclohexanol or 1-propanol as reaction solvent. Their morphology and structure properties were systematically characterized. The NO2-sensing properties of the sensors based on nanowires and nanorods were investigated at 100 degrees C up to 250 degrees C over NO2 concentration ranging from 1 ppm to 20 ppm. The results indicate that both nanowires and nanorods exhibit reversible response to different concentrations of NO2, and the highest gas response is achieved at 150 degrees C. In comparison with nanorods, nanowires showed a much quicker response characteristic and a relative higher response value to the same concentration of NO2 gas due to the smaller diameter and larger specific surface area. (C) 2011 Elsevier B.V. All rights reserved.