Facile synthesis of reduced graphene oxide/hexagonal WO_3 nanosheets composites with enhanced H_2S sensing properties

摘要

Reduced graphene oxide/hexagonal WO_3 (rGO/h-WO_3) nanosheets composites were synthesized through hydrothermal method and post-calcination treatment. The products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N_2 adsorption-desorption, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA). The results showed that two-dimensional (2D) h-WO_3 nanosheets with porous structure were attached on rGO to construct 3D rGO/h-WO_3 hybrid nanocomposites. This 3D hybrid nanostructure provided many channels for gas diffusion. The fabricated sensor based on 3.8 wt% rGO/h-WO_3 composites showed good gas sensing response to H_2S. The sensitivity of the sensor was about 168.58 toward 40 ppm H_2S, which was 3.7 times higher than that of pure WO_3, and the response time was 7s when exposed to 10ppm H_2S. Moreover, the sensor showed low detection limit (10ppb), wide linear range and high selectivity to H_2S. The improved gas sensing properties of 3.8 wt% rGO/h-WO_3 composites may be attributed to the formation of hetero-junctions, good accepting/transporting electrons properties of rGO and effective gas transport channels in 3D hybrid nanostructure.