Facile fabrication and enhanced gas sensing properties of hierarchical MoO3 nanostructures

Hierarchical nanostructures are very promising gas-sensing materials due to their well-aligned structures with less agglomerated configurations. In this paper, hierarchical MoO3 nanostructures were successfully synthesized through the oxidization conversion of hydrothermally synthesized MoS2 precursors. The morphology and microstructure were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric and differential scanning calorimeter analysis (TG-DSC), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), and N-2 adsorption-desorption analyses. The results clearly reveal that MoS2 precursors can completely transfer into MoO3 via the annealing process at 400 degrees C. And the as-prepared hierarchical MoO3 nanostructures are about 500 nm in diameter, which are constructed by relatively densely packed nanosheets with the thickness of around 5-10 nm. Based on the experimental results, a possible mechanism for the formation of hierarchical MoO3 nanostructures was speculated. Furthermore, owing to the well-defined and uniform hierarchical structure, the sensor based on hierarchical MoO3 nanostructures shows superior gas sensing performance towards ethanol and it maybe has potential application in the detection of ethanol vapors.