Investigation on NO2 sensing behavior of WO3 nanograined resistive sensors

The gas sensing performance of chemoresistive metal-oxide sensors are influenced by different factors concerning both the material chemical structure and the sensor preparation. Among them, the grain size is a critical factor that plays an important role in determining the gas response of the sensor. In this work the sensing behavior of a WO
3
nanograined resistive sensor at low concentrations of NO
2
is investigated by means of experimental tests. The realized sensor shows outstanding sensing performance in the observed working temperature range between 175 °C - 265 °C for NO
2
concentrations below 10 ppm. The analysis carried out also provides important information on the influence of the nanostructure of the film in the dynamics of the response of the sensor to the gas and to the chemical reactions involving the material surface.