Solid-electrolyte amperometric sensor for measuring NO in air, nitrogen, and nitrogen-oxygen gas mixtures

Abstract

In the present research, the possibility of using the electrochemical amperometric sensor with a diffusion barrier, based on yttria-stabilized zirconia electrolyte and two Pt electrodes, for measuring small NO concentration (below 1 vol.%) in nitrogen, air, and О2 + N2 gas mixtures, was discussed. The sensor testing at 450–600°С demonstrated high stability and reproducibility of results and good dynamic characteristics. It was shown that the sensor exhibits specific values of the limiting current for different contents of nitric oxide in the considered gas mixtures that allows precise determining of small NO concentrations. The presence of NO in the gas mixtures containing free oxygen was found to significantly increase the sensor limiting current. The catalytic role of NO molecules in oxygen exchange at the triple phase boundary between the solid electrolyte, electrode, and gas was discussed. Effect of NO2, CO2, and H2O impurities on the sensor performance was studied.