Investigations into the development of an alternative concept of a potentiometric CO2 sensor

Potentiometric measurements were carried out with various types of solid electrolyte galvanic cells that operate as an oxygen concentration chain and use an alkali carbonate in equilibrium with O-2 and CO2 as main component of the gas sensitive electrode. It turns out that the feasibility of such a kind of a CO2 sensor strongly depends on the material that hosts the substance acting as an intermediator between the chemical potential of the alkali metal, resulting from the carbonate, and the oxygen potential. The best sensor properties were obtained by a cell in which an electronically short-circuited phase mixture of Na-(beta+beta ")-Al2O3 is utilized as an interlayer between the oxygen ion conducting solid electrolyte and the gas sensitive carbonate layer.