WO 3 is one of the inspiring sensing materials that show high response to O 3 ; an efficient fabrication of WO 3 film with incorporation of complementary additives is essential for enhanced sensitivity. Here we report film deposition by liquid flame spraying, characterization of nanostructured WO 3 -reduced graphene oxide (rGO) composites and their gas-sensing activities to O 3 . The starting feedstock was prepared from WC l6 and rGO for pyrolysis synthesis by flame spraying. Nano-porous WO 3 -rGO films were successfully fabricated and characterized by transmission electron microscopy , field emission scanning electron microscopy , Raman spectrometry , thermal analyses and X-ray diffraction. Nanosized WO 3 grains exhibited oriented nucleation on rGO flakes whereas rGO retained intact its nano-structural features after spraying. Constrained grain growth of WO 3 of 60–70 nm in size was realized in the rGO-containing films with as compared to ~220 nm in the pure WO 3 film. The WO 3 -rGO film sensors showed quicker response to O 3 and faster recovery than rGO-free WO 3 film sensors. Addition of rGO in 1.0 wt% or 3.0 wt% in the films caused a significantly reduced effective working temperature of the film sensors from ~ 250 °C to ~ 150 °C.
Two-dimensional transition-metal dichalcogenides, such as tungsten disulfide (WS 2 ), have been actively studied as suitable candidates for anode materials used in lithium ion batteries recently, due to their remarkable ion intercalation properties. However, the difficulties in the synthesis of phase-pure WS 2 , restacking between WS 2 nanosheets, low electronic conductivity and brittle nature of WS 2 severely limit its Li-ion batteries application. Here, we adopt a one-pot method for synthesizing of WS 2 /reduced Graphene Oxide (rGO) composite to improve the battery performance dramatically. The WS 2 /rGO anode shows a stable discharge capacity of 431.2 mAh/g, at a current density of 0.1 A/g after 100 cycles, while the capacity of bare WS 2 is only 65.5 mAh/g under the same condition. The added graphene oxide is reduced to rGO in reaction process and constitute stable composite with WS 2 , not only avoiding the restacking between WS 2 nanosheets and improving the conductive properties, but also promoting the reduction of WO 3 effectively. Our work may provide a possible route to avoid oxygen impurities in transition metal dichalcogenides .
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