Tubular amperometric high-temperature sensors:: simultaneous determination of oxygen, nitrogen oxides and combustible components

Tubular amperometric sensors based on stabilized zirconia solid electrolyte with two working electrodes have been studied experimentally with respect to the simultaneous measurements of oxygen and nitrogen oxides, and of oxygen and combustible gas mixtures. Sensors with different types of working electrodes have been optimized for specific gas analytical problems. An almost complete separation of the sensor signals to defined gas components has been achieved by optimization of the working parameters of the electrodes. Cross-sensitivities to oxygen-containing and to combustible gas components have been measured. Cross-interference effects from CO2 and H2O at O-2/NOx sensors were minimized by properly adjusting the electrode potentials. Cross-effects on O-2/HCx-sensors have been found to be even lower. The results demonstrate a new level of performance for new applications of multi-electrode solid electrolyte amperometric sensors. (C) 2000 Elsevier Science S.A. All rights reserved.