Synthesis and NO2-sensing properties of one-dimensional tungsten oxide nanowire bundles.

Tungsten oxide nanowires were synthesized by solvothermal method with tungsten hexachloride (WCl6) as precursor. X-ray diffraction, field emission scanning electron microscope and transmission electron microscope characterizations indicated that the as-synthesized nanowires are single phase monoclinic W18O49. With WCl6 concentration increasing, the bundled nanowire became shorter and thicker. The gas-sensing properties of W18O49 nanowire towards NO2 gas were evaluated and the results showed that the optimal gas sensitivity is achieved at 150 degrees C and the thinner nanowire exhibits the higher sensitivity. The results indicate that tungsten oxide nanowire is a promising gas-sensing material for high performance and low power cost NO2 gas sensor.