Room-temperature ppb-level SO gas sensors based on RGO/WO and MWCNTs/WO nanocomposites.

ppb-level SO gas sensors for use at room temperature were fabricated using an in situ one-pot polyol method combined with metal organic decomposition (MOD) of nanocomposite films of multi-walled carbon nanotubes/WO (MWCNTs/WO) and reduced graphene oxide/WO (RGO/WO) on an alumina substrate. Comparative gas sensing results showed that the SO gas sensor based on the RGO/WO nanocomposite film exhibited a higher response compared with the MWCNTs/WO nanocomposite film and pristine WO film, sensing SO gas at very low (ppb-level) concentrations at room temperature. The SO gas sensor based on the RGO/WO nanocomposite film also had fast response and recovery times, good reproducibility, and the lowest detection limit. The formation of new conducting pathways and the spread of the depletion layers at the interface of the doped MWCNTs or RGO and the WO matrix upon interaction with SO gas were responsible for the enhanced response.