CO2 monitoring by solid state limiting-current sensors

The aim of this contribution is to present some results on CO2 determination in N2/CO2 gas mixtures. The sensor under investigation is a zirconia (solid-electrolyte) electrolysis cell operating in a limiting-current mode. The diffusion of the gaseous species to the reduction electrode is limited by a pinhole in a pellet sealed to the cathodic side of the cell. The experiments are carried out as a function of CO2 concentration and temperature. It is found that the limiting current depends on the CO2 partial pressure, as theoretically predicted. The possibility of determining CO2 in nitrogen in a wide range of concentrations is confirmed