Electrospun rGO-PVDF/WO₃ composite fibers for SO₂ sensing

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.