Effect of Cr2O3 electrode morphology on the nitric oxide response of a stabilized zirconia sensor

Electrochemical sensors using a porous Cr2O3 Sensing electrode and an yttria- stabilized zirconia electrolyte were fabricated and tested for their NO sensitivity. The electrodes were fabricated by colloidal spray deposition of Cr2O3 powder, followed by sintering at 1000-1200 degreesC. The effects of sintering temperature on the electrode thickness and microstructure are discussed. The observed dependence of the NO sensitivity, in the temperature range of 500-600 degreesC, on both the electrode thickness and microstructure indicates competing mechanisms are involved in the sensor response. The reaction of NO and O-2 to form NO at the electrode surface was explored using a cherm luminescent NOx analyzer. The data indicate that sintering temperature also affects the catalytic activity of the Cr2O3. (C) 2003 Elsevier B.V. All rights reserved.