Porous corundum-type In2O3 nanosheets: Synthesis and NO2 sensing properties

Porous corundum-type In2O3 (rhombohedra In2O3, rh-In2O3) nanosheets with unique shoeprint morphology are fabricated successfully by a facile, template-free solvent-thermal method. The products are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and N2 adsorption–desorption. The response of the porous rh-In2O3 nanosheets sensor to 50 ppm NO2 is about 164, and the response/recovery times are not exceeding 5 s and 14 s, respectively. Porous lamellar structure could increase the number of the active sites and speed up the gas transportation, which is helpful for the enhancement of the response and rapid adsorption/desorption. The effect of morphology on the gas sensing responses is investigated. Compared with the nonporous rh-In2O3 nanosheets sensor, the porous rh-In2O3 nanosheets sensor exhibits significantly enhanced sensing performances toward NO2. Porous rh-In2O3 nanosheets sensors show a long-term stability, which might be ascribed to the avoidance of aggregation of the nanostructures.