Hydrothermal synthesis of In2O3 for detecting H2S in air

Nanocrystalline In2O3 gas sensing material was prepared by sintering a precursor In(OH)3 at 600 °C which was hydrothermally synthesized at 250 °C for 24 h by using InCl3·4H2O as a starting material. The nanopowder was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetry–differential scanning calorimetry (TG–DSC) and X-ray photoelectron spectrometer (XPS). The results indicated that the precursor of indium oxide was cubic indium hydroxide with range size of 50–80 nm, and indium oxide was composed of In and O. Gas sensing properties of the sensors were tested by mixing a gas in air at static state, the tested results showed that the sensor based on In2O3 nanocrystals had satisfying H2S gas sensing properties at rather low temperature.