Flower-like SnO₂/g-C₃N₄ nanocomposites were synthesized via a facile hydrothermal method by using SnCl₄·5H₂O and urea as the precursor. The structure and morphology of the as-synthesized samples were characterized by using the X-ray powder diffraction (XRD), electron microscopy (FESEM and TEM), and Fourier transform infrared spectrometer (FT-IR) techniques. SnO₂ displays the unique 3D flower-like microstructure assembled with many uniform nanorods with the lengths and diameters of about 400-600 nm and 50-100 nm, respectively. For the SnO₂/g-C₃N₄ composites, SnO₂ flower-like nanorods were coupled by a lamellar structure 2D g-C₃N₄. Gas sensing performance test results indicated that the response of the sensor based on 7 wt. % 2D g-C₃N₄-decorated SnO₂ composite to 500 ppm ethanol vapor was 150 at 340 °C, which was 3.5 times higher than that of the pure flower-like SnO₂ nanorods-based sensor. The gas sensing mechanism of the g-C₃N₄nanosheets-decorated SnO₂ flower-like nanorods was discussed in relation to the heterojunction structure between g-C₃N₄ and SnO₂.
Keywords: flower-like SnO2 nanorod; gas sensor; graphitic carbon nitride; microstructure; nanocomposites.