High gas sensor performance of WO3 nanofibers prepared by electrospinning

Abstract

WO3 is a widely studied gas sensor material that commonly exhibits excellent sensitivity and selectivity toward NO2 detection. In this study, the influence of the heating rate on the thickness and grain size of WO3 nanofibers synthesized by electrospinning was evaluated. The materials were analyzed using XRD, Raman, and UV-Vis spectroscopies, as well as FEG-SEM, TG-DTA, and the BET method. Results showed that continuous nanofibers with particle size dependent on the heating rate were obtained at 500 °C. The gas sensing performance of WO3 nanofibers calcined at 10 °C/min (NF500–10) was investigated due to its higher surface area. NF500–10 device presented a high sensor signal for low and high NO2 concentrations at temperatures ranging from 150 °C to 300 °C. The sensor signals for 25 ppm of NO2 at 150 °C are substantially higher than those of several previous reports. Moreover, high selectivity against potential interferents (H2 and CO) was observed at all operating temperatures. A sensing mechanism based on the interaction between NO2 molecules and the surface of the WO3 nanofibers was proposed to explain the high sensor response. In conclusion, WO3 nanofibers were found to be an attractive sensing material to detect both low and high NO2 concentrations with excellent selectivity.