The sensor properties of SnO2 • In2O3 nanocomposite oxides in the detection of hydrogen in air

The sensor properties of In2O3 center dot SnO2 polycrystalline films having different compositions were studied in the detection of 2% hydrogen in air over the temperature range 330-530A degrees C. Films containing 19% In2O3 were most sensitive to hydrogen. The temperature dependence of the sensitivity of sensors passed a maximum, the position of which depended on the composition of the film. The temperature at which sensor sensitivity was maximum decreased as the content of indium oxide increased. This temperature was 485A degrees C for the SnO2 film and 425A degrees C for the In2O3 film. The response and relaxation times of sensors also decreased as the amount of In2O3 in the composite metal oxide film increased. Possible mechanisms of the sensor sensitivity of the films are discussed.