Highly Sensitive Ethanol Gas Sensor Based on Ag Nanoparticles Decorated In₂O₃

Ag nanoparticle decorated In₂O₃ composites for high sensitivity and high selectivity detection of ethanol were prepared by hydrothermal and annealing methods. The effects of Ag content on the sensing properties of Ag decorated In₂O₃ sensors were also investigated. It was found that all Ag decorated In₂O₃ sensors exhibited better sensing performance in terms of sensitivity and selectivity compared to pure In₂O₃ sensors. By optimizing the addition amount of Ag, the 7%-Ag/In₂O₃ sensor showed the highest response to ethanol (35.6 vs. 100 ppm, ppm=parts per million), which was about seven times higher than that of the pure In₂O₃ sensor at 270 °C. The improved performance of the Ag-In₂O₃ composite sensor can be attributed to the catalytic effect of silver and the Schottky barrier formed at the Ag-In₂O₃ interface.