Modelling of SO2 detection by tin dioxide gas sensors

Abstract In studying tin dioxide-based gas sensors under sulphur dioxide, we have confirmed phenomena at the gas/semi-conductor interface during the first and subsequent detections. According to Lalauze et al. [1] , the tin dioxide gas sensor is modified by the first SO 2 exposure. It appears that modification is due to the adsorption of sulphite and sulphate on the semi-conductor surface. After the first detection, the gas sensor response peaks at 200°C. We have shown that this peak is connected with quantity of SO 2 adsorbed during detection at high temperatures (>200°C), and not low ones. Finally, we propose two mechanisms to explain these results.