Electrical Properties of Gas Sensor Materials

摘要

Chemical all solid state gas sensors are examined. Target gases were SOx, NOx andH2 for Nernst sensors and CO, alcohols, and alkanes for semiconductor sensors. For the first ones, the study was focused on the selection and the characterization of suitable electrolyte and electrode materials in order to optimize sensor properties such as stability or reliability, particularly by means of impedance spectroscopy. NiO/NiSO4 is found to be an adequate solid reference electrode and Na2SO4 is proved to be a solid electrolyte with good electrical properties and mechanical integrity. The stability and temperature dependence and the cross sensitivity of commercially available semiconductor sensors was studied but they showed too weak a selectivity to be reasonably used for quantitative measurements.