Synthesis, growth kinetics and ultra-sensitive performance of electrospun WO3 nanofibers for NO2 detection

Abstract

WO3 nanofibers are fabricated as NO2 sensing materials by a simple electrospinning technique followed with calcination treatment. The obtained WO3 nanofibers are constructed by nanograins located along the 1 D direction. The growth kinetics of WO3 nanograins in individual nanofibers are studied by varying calcination temperatures and times. The calculated growth exponent value (n = 2.90) suggests that WO3 nanograins growth in nanofibers is developed by lattice diffusion in the pore control scheme. Subsequently, NO2 sensing performance of the as-synthesized WO3 nanofibers is evaluated, which shows excellent performance for NO2 detection at 200 °C, including high response (12.523) and fast response/recovery times (11 s/26 s) to 1 ppm NO2. Moreover, the WO3 sensor displays excellent anti-interference ability toward several interfering gases. The stability of the WO3 sensor is further confirmed by 14 days of continuous testing. Compared with previously reported works, the WO3 sensor still demonstrates outstanding gas sensing properties due to its unique advantages such as 1D nanofibrous structures, high BET surface area, and rich oxygen vacancies.