Tungsten Sulfide Nanoflakes: Synthesis by Electrospinning and Their Gas Sensing Properties

Abstract Tungsten sulfide (WS 2 ) nanoflakes were successfully prepared via electrospinning with polyvinylpyrrolidone (PVP) as organic solvent. In addition, Ag-deposited WS 2 (Ag-WS 2 ) was obtained by chemical blending/calcination method. The structure and morphology of as-prepared materials were characterised by powder X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The XRD result shows that the prepared WS 2 has a graphene-like structure with P 63/mmc space group symmetry. The SEM illuminates that the sensing samples have nanoflake appearance. Furthermore, heater-type gas sensors were fabricated based on WS 2 and Ag-WS 2 nanomaterials. The sensing responses of WS 2 and Ag-WS 2 on the ammonia (NH 3 ), ethanol (C 2 H 5 OH), and acetone (C 3 H 6 O) were investigated at about 220°C. The results indicate that gas sensor based on WS 2 and Ag-WS 2 nanoflakes has 60 ppm sensing threshold value for ammonia. One possible gas sensing mechanism of WS 2 and Ag-WS 2 gas sensors is surface control via charge transfer.