Huihui Yan

Flower-like In2O3 hierarchical nanostructures: synthesis, characterization, and gas sensing properties

Hierarchical In2O3 nanostructures with flower-like morphology were synthesized by annealing In(OH)3 precursors prepared via a one-step hydrothermal method using the mixed solution of N,N-dimethylformamide (DMF) and deionized water as solvent. The crystal structure and morphology of the obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption–desorption analyses. The results revealed that the synthesized flower-like In2O3 hierarchical nanostructures were constructed from In2O3 nanoplates which connected with each other to form flower-like architecture. On the basis of experimental results, a possible mechanism for the formation of flower-like In2O3 hierarchical nanostructures was considered. Moreover, gas sensing investigation showed that the sensor based on flower-like In2O3 hierarchical nanostructures exhibited a superior response, good selectivity and stability to ethanol gas. The enhancement in gas sensing properties was attributed to their unique structure, large surface areas, and more surface active sites.

Dispersed SnO2 nanoparticles on MoS2 nanosheets for superior gas-sensing performances to ethanol

The unique properties of MoS2 nanosheets make them a promising supporting substrate for preventing the interparticle aggregation of metal–oxide–semiconductor nanomaterials. Novel composites were successfully obtained by a two-step low temperature hydrothermal method for the synthesis of SnO2 nanoparticles dispersing on the surfaces of MoS2 nanosheets. The morphology and structure of the as-prepared samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). Owing to the supporting substrate of specific two-dimensional MoS2 nanosheets and the superior gas-sensing performance offered by ultrasmall SnO2 nanoparticles, the sensor based on SnO2@MoS2 composites exhibits high response and good selectivity to ethanol gas.

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 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.