Abstract: Indium oxide (In₂O₃) sample was synthesized by using SBA15 hard templates replication technique. The crystal structure, grain size, morphology and bandgap width of the sample were characterized and by Xray diffraction (XRD), scanning electron microscopy (SEM) and UVVisible spectra, and the influence mechanism of nanostructure on gas sensing property was analyzed. The results show that the structure of sample is nano arrays. The threedimensional In₂O₃ nano arrays are composed of the regular arrangement of single crystal subglobose In₂O₃ particles with a diameter of about 15 nm, and the spacing of interwires is about 1 nm and the bandgap width is 3.63 eV. When the temperature is 320 ℃, the volume ratio of ethanol gas in air is 10^-4, the sensitivity is 42.3. The gas sensing properties of the nanostructured samples are better than those of the same grade nanoparticles and mesoporous nanomaterials.

Key words: nanowire array, degree of order of nanostructure, mesoporous structure, gas sensing property