Solid electrolyte NOx sensor using pyrochlore-type oxide electrode

Solid electrolyte electrochemical devices based on sodium super-ionic conductor (NASICON: Na1 + xZr2SixP3 - xO12) and pyrochlore-type oxide (Pb2M2O7 - y: M = Ir, Ru1 - xPbx; x = 0-0.75) electrodes were found to exit good performance for the potentiometric sensing of NO as well as NO2 at 400 degrees C. The EMF responses were almost linear to the logarithm of NO or NO2 concentration. Among the elements tested, the device attached with Pb2Ru1.5Pb0.5O7 - y electrode gave excellent NO sensing properties, and the EMF changed with changing gas concentration of NO diluted in N-2 or NO diluted in an O-2 and N-2 mixture with negative or positive slope, respectively, while it kept almost constant to the concentration change of NO2 and CO2 dilated in air. (C) 1998 Elsevier Science S.A. All rights reserved.