Fast detection of alcohols by novel sea cucumber-like indium tungsten oxide

Abstract Novel sea cucumber-like indium tungsten oxide is synthesized by a one-step solvothermal method without surfactant. Interestingly, sensors based on this kind of indium tungsten oxide achieve the detection of some target gases with certain characteristics, which has been rarely reported until now. In this paper, response of the sensor to 200 ppm of methanol, ethanol, n-propanol, n-butanol, n-pentanol and n-hexanol is 11.4, 20.5, 22.3, 23.7, 23.2 and 17.1, respectively, which is significantly higher than to other gases, indicating that the cucumber-like indium tungsten oxide is especially sensitive to straight-chain alcohols with -OH function group at the end of the chain. In addition, the response time is 2 s, 2 s, 2 s, 2 s, 2 s and 17 s, respectively, which facilitates rapid detection in real application. The sea cucumber-like nanostructures can be only formed under the condition that molar ratio of In(NO3)3·4.5H2O to Na2WO4·2H2O is 2:1 and volume ratio of alcohol to deionized water is 3:2. The sea cucumber-like nanostructures possess nanothorns vertically distributed on the surface of the main nanoellipsoid. The long axis of the nanoellipsoid is about 800 nm, and the short axis is about 270 nm. This is a kind of non-stoichiometric ratio compound consisting of indium, tungsten and oxide elements speculated by XRD, XPS and EDX characterizations. The field emission scanning electron microscopy characterization reveals the growth process and the morphology evolution of the material.