A review of electrolyte and electrode materials for high temperature electrochemical CO2 and SO2 gas sensors

Carbon dioxide and sulfur dioxide are two common combustion products, so monitoring their contents in exhaust gases is important to reduce harmful emissions. Solid electrolyte based sensors are well suited to the high temperature aggressive environments in combustion environments. However, the design of effective high temperature electrochemical sensors for CO2 and SO2 requires strategic combinations of electrolyte and electrode materials to provide satisfactory response and stability. The approaches and materials used in the development of CO2 and SO2 sensors, many of which are common to both types of sensors, are reviewed in this paper.