Electrodes for potentiometric solid-electrolyte sensors with nonseparated gas spaces for measuring the contents of combustible CO and H2 gases in gas mixtures

Abstract

The results of studies of oxide electrodes for solid electrolyte potentiometric sensors for analyzing air-combustible gas (combustible gas is CO or H2) and nitrogen-combustible gas mixtures are presented. The characteristics of the electrochemical cells based on Zr0.82Y0.18O1.9 and Ce0.8(Sm0.8Ca0.2)0.2O2-δ solid electrolytes were considered. The dependences of the response of the potential of the measuring electrodes of simple oxides SnO2 and ZnO and complex oxides with a perovskite structure La0.8Sr0.2CrO3 and La0.6Sr0.4MnO3 on the concentration of carbon monoxide and hydrogen in air were studied. The most promising application was found to be hydrogen determination in the air-hydrogen mixture for sensors with a SnO2 measuring electrode with a zirconia electrolyte and CO analysis in the air-carbon monoxide mixture for sensors with a ZnO measuring electrode. The measuring electrodes and SnO2, La0.8Sr0.2CrO3, ZnO, and La0.6Sr0.4MnO3 on ceria and zirconia electrolytes showed satisfactory sensitivity to hydrogen in the hydrogen-nitrogen gas mixture at hydrogen concentrations of up to 100 ppm and at temperatures of 500–550°C.