NO2 Gas Sensing Properties of Nano-Sized In2O3 Doped WO3 Powders Prepared from Polymer Solution Route

In2O3 doped WO3 powders were prepared by a polymer solution route and their NO2 gas sensing properties were analyzed. The synthesized powders showed nano-sized particles with specific surface areas of 6.01~21.5 m2/g and the particle size and shape changed according to the content of In2O3. The gas sensors fabricated with the synthesized powders were tested at operating temperatures of 400~500 °C and 100~500 ppm concentrations of NO2 atmosphere. The particle size and In2O3 content affected on the initial sensor resistance in an air atmosphere. The highest sensitivity (8.57 at 500 °C), which was 1.77 higher than the sensor consisting of the pure WO3 sample, was measured in the 0.5 mol% In2O3 doping sample. In addition, the response time and recovery time were improved by the addition of In2O3.