W-doped NiO as a material for selective resistive ethanol sensors.

• The introduction of W can reduce the crystallinity of NiO. • W dopants may contribute to the generation of oxygen vacancies and decrease the hole concentration. • The response of 4 % W-NiO NTs with rich oxygen vacancies toward 100 ppm ethanol is 40.56 at 200 °C. • The concentration of oxygen in the background gas has a significant effect on the performance of the sensor. • The background oxygen could increase the sensor's response to ethanol. W-doped NiO nanotubes (NTs) were successfully synthesized for efficient sensing of ethanol vapor using a low cost and economical electrospinning method. The response (resistance ratio) of sensor based on 4 % W-NiO NTs to100 ppm ethanol is as high as 40.56 at 200 °C, which is 10 times higher than that of pure NiO sensor. This significant enhancement in sensor response can be attributed to the change in morphology, increase in oxygen vacancies, and the decrease in hole concentration in NiO by W doping. Based on the adsorption and desorption theory of oxygen, we also demonstrated that the atmospheric oxygen content can improve the sensor response and shorten the response time by increasing the amount of adsorbed oxygen. [ABSTRACT FROM AUTHOR]