A novel CO2 sensor based on changes in conductivity of metal oxides

A low-cost CO2 sensor in thick film technology has been developed using BaTiO3 and various semiconducting oxides. The sensing principle of this new CO2 sensor is based on changes in conductance of the metal oxides in the presence of carbon dioxide. In this report, effects of preparation parameters and effects of various additives on the sensitivity of the CO2 sensor are described, and measurements of the sensor resistance as a function of CO2 concentration are presented. The sensor is applicable over a wide range of CO2 concentrations. Humidity changes have only minor effects on the sensor response.