Enhanced sensitive and selective xylene sensors using W-doped NiO nanotubes

Pure and 1-4 mol% W-doped NiO nanotubes were prepared by electrospinning. Sensors based on these nanotubes were fabricated by hot pressing the nanomaterials on the ceramic plates. The responses (S=R-g/R-a, where R-g is the resistance in gas and R-a is the resistance in air) to 200 ppm xylene, ethanol, acetone, benzene, toluene, methanol and formaldehyde are significantly enhanced by W doping of NiO nanotubes, while the response of pure NiO nanotubes are very low. In particular, the sensors based on W-doped NiO nanotubes, in which the molar ratio of W6+:Ni2+ is 2:100, exhibit highest response toward 200 ppm xylene, having a response about 8.74, which is almost 3.3 times higher than that of sensor based on pure NiO nanotubes. The results of sensing properties indicate that the xylene sensors based on the W-doped NiO nanotubes exhibit good selectivity, repeatability and long term stability characteristics, which are promising for xylene sensors used to monitor air-quality and environmental. (C) 2015 Elsevier B.V. All rights reserved.