Electrospun rGO-PVDF/WO3 composite fibers for SO2 sensing

Abstract

Developing highly selective and sensitive SO2 sensors is essential due to the excessive presence of SO2 in the environment which can cause respiratory illness and acid rain. Semiconducting metal oxides are the materials most used for the development of SO2 sensors; however, they still suffer from sensitivity, selectivity, low-temperature operation, low detection limit, and slow response/recovery time for real-field applications. In this work, rGO-PVDF/WO3 composite fibre-based sensors are developed via electrospinning technique. The electrospun rGO-PVDF/WO3 were characterized for their structural morphology, thermal stability, crystal structure, and their SO2 sensing capability. The results show that the electrospun rGO-PVDF/WO3 sensor (containing 10 mL GO) leads the most improved SO2 sensing performance of all tested sensors in this work, with a response of 11.08 and 22.06 at SO2 concentrations of 60 and 80 ppm, respectively. The 10 mL-rGO-PDVF/WO3 composite nanofibers also demonstrated good selectivity and stability for SO2. The improvement in gas sensitivity is due to the synergistic effect of forming an ohmic contact between the rGO nanosheets, PVDF fibers, and the WO3 nanograins. The good surface properties such as high surface area (10.64 m2/g) and porous structure of 10 mL-rGO-PDVF/WO3 composite nanofibers have also contributed to the SO2 gas sensing performance. The results show that the composite nanofibers rGO-PVDF/WO3 can be used to detect low concentrations of SO2 and could be used to monitor the environment.