Synthesis of hierarchical SnO2 nanostructures assembled with nanosheets and their improved gas sensing properties

Well-defined three-dimensional (3D) hierarchical tin dioxide (SnO2) nanoflowers (NFs) constructed by two-dimensional (2D) nanosheets (NSs) are successfully fabricated by a simple one-pot low-temperature (90 °C) hydrothermal strategy. The influence of the experiment parameters on the morphology of the products is investigated in detail. Field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) demonstrate that the size and shape of the 3D hierarchical SnO2 NFs can be tailored by modulating the molar ratio of OH− to Sn2+, reaction time and reaction temperature in the process of hydrothermal synthesis. A possible formation process and growth mechanism for such fabricated 3D hierarchical SnO2 nanostructures has been proposed based on the experimental results. The gas sensing tests of the SnO2 NF sensor for several reducing volatile organic compounds (VOCs) including ethanol, n-butanol, acetone, methanol, chloroform and benzene have been performed at the relatively low operating temperature of 240 °C. The excellent gas sensing performances of the unique 3D hierarchical SnO2 NFs at low operating temperature of 240 °C indicate their potential application as gas sensors. The unique 3D hierarchical SnO2 NFs with high accessible surface area and commodious inter space can also be expected to use as catalyst, dye-sensitive solar cell and Li ion battery materials.