Ethanol Sensors Based on Porous In₂O₃ Nanosheet-Assembled Micro-Flowers

By controlling the hydrothermal time, porous In₂O₃ nanosheet-assembled micro-flowers were successfully synthesized by a one-step method. The crystal structure, microstructure, and internal structure of the prepared samples were represented by an x-ray structure diffractometry, scanning electron microscopy, and transmission electron microscopy, respectively. The characterization results showed that when the hydrothermal time was 8 h, the In₂O₃ nano materials presented a flower-like structure assembled by In₂O₃ porous nanosheets. After successfully preparing the In₂O₃ gas sensor, the gas sensing was fully studied. The results show that the In₂O₃ gas sensor had an excellent gas sensing response to ethanol, and the material prepared under 8 h hydrothermal conditions had the best gas sensing property. At the optimum working temperature of 270 °C, the highest response value could reach 66, with a response time of 12.4 s and recovery time of 10.4 s, respectively. In addition, the prepared In₂O₃ gas sensor had a wide detection range for ethanol concentration, and still had obvious response for 500 ppb ethanol. Furthermore, the gas sensing mechanism of In₂O₃ micro-flowers was also studied in detail.