Graphene-wrapped WO3 nanoparticles with improved performances in electrical conductivity and gas sensing properties

WO3/graphene (GN) nanocomposites have been successfully synthesized using a facile three-step synthesis. First, an SrWO4/graphene oxide (GO) precursor was synthesized by homogeneous precipitation; second, the SrWO4/GO precursor was transformed into WO3/GO hybrids by acidification; and third, the WO3/GO hybrids were reduced to WO3/GN via UV-assisted photoreduction in water instead of general alcoholic solvent at room temperature. The resulting WO3 nanoparticles anchored on graphene sheets as spacers to keep the neighboring sheets separated are approximately quadrangular with a side length of 50-200 nm. Compared with WO3/GO hybrids, WO3/GN nanocomposites show an enhanced electrical conductivity, which results in an improved gas sensing towards alcohol. This work provides a new insight into the fabrication of tungstate-graphene composites and facilitates their application in future.