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

Nanowire bundles of tungsten oxide were synthesized by solvothermal method with tungsten hexachloride (WCl₆) as precursor and 1-propanol as solvent. The synthesis processes were preformed at different WCl₆ concentration. Long W₁₈O₄₉ nanowire bundles with effective surface area of 89.89 m²/g was synthesized at a WCl₆ concentration of 0.01M. With concentration increasing, the nanowire bundles became shorter and thicker and finally a nanoplates structure formed. The measurements for NO₂-sensing properties indicated that the longer and thinner W₁₈O₄₉ nanowire bundles showed the quickest response/recovery and the highest sensitivity to different concentration NO₂ gas due to their special structural feature, and the response time, recovery time and sensitivity are 19 s, 112 s and 123.6 to 5 ppm NO₂, respectively.