Abstract
There have been increasing demands for adequate gas sensors to monitor O3, a respiratory irritant gas associated with a spectrum of adverse health events. Here we report film construction by liquid flame spray route and characterization of nanostructured WO3-reduced graphene oxide (rGO) composites and their gas-sensing activities to O3. The starting feedstock was prepared from WCl6 and rGO for pyrolysis synthesis by flame spray. Nanosized WO3 grains exhibited oriented nucleation on rGO flakes and rGO retained intact nano-structural features after the spraying. Constrained grain growth of WO3 was realized in the rGO-containing films with 60-70 nm size as compared to ~220 nm in the pure WO3 film. The WO3-rGO film sensors showed quicker response to O3 and faster recovery than the rGO-free WO3 film sensors. Addition of rGO in 1.0wt.% or 3.0wt.% in the films caused significantly reduced effective working temperature of the film sensors from ~250°C to ~150°C. These results might shed some light on liquid flame spray fabrication of novel functional nanocomposites for gas-sensing applications.
