Facile fabrication and enhanced gas sensing properties of hierarchical MoO3 nanostructures

Abstract

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 N₂ adsorption–desorption analyses. The results clearly reveal that MoS₂ precursors can completely transfer into MoO₃ via the annealing process at 400 °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.