The NO2 response of solid electrolyte sensors made using nano-sized LaFeO3electrodes

Electrochemical cells were prepared coupling an oxygen ionic conductor (Y2O 3-stabilized ZrO2:YSZ) with a semiconducting oxide (LaFeO3) electrode. Pt w as used as the counter electrode. These devices showed promising NO2 sensin g performance at 400 and 450 degreesC. The electromotive force (EMF) value of the (Pt)LaFeO3/YSZ/Pt sensor increased in NO2 atmospheres with a fast re sponse time. The polarization curves showed non-linear behavior in air and NO2. The non-linearity was attributed to the potential drop at the electrod e interfaces. Electrochemical impedance spectroscopy (EIS) analysis of the devices showed that the resistance and reactance at the electrolyte/electro de interface decreased upon introduction of 100 ppm NO2 in air, because of a lower electrode overvoltage. (C) 2001 Elsevier Science B.V. All rights re served.