Correlation of sensing behavior of mixed potential sensors with chemical and electrochemical properties of electrodes

• Published in: Solid state ionics Vol. 171; no. 3; pp. 183 - 190
• Main Authors: Szabo, Nicholas F, Dutta, Prabir K
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.07.2004
• Subjects: Mixed potential; Nitrogen oxides; NO x conversion; NO x sensor; Oxygen sensing; Polarization; Polarization; Nitrogen oxides; NO x sensor; Oxygen sensing; NO x conversion; Mixed potential
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2004.04.019

The mixed potential response for NO and NO 2 from two different oxide electrodes on yttria-stabilized zirconia (YSZ) was examined at 500 °C. The two electrodes were La 0.6Sr 0.4Fe 0.8Co 0.2O 3 (LSFCO) and Cr 2O 3. Sensors made with LSFCO electrodes had consistently lower sensitivity towards NO x as compared to those with Cr 2O 3 and the focus of this paper is to understand the fundamental reasons for the differences in electrode sensitivity. Catalytic activity of the electrodes towards equilibration of NO/NO 2 and electrical properties of the electrodes for O 2/O 2− chemistry were examined. Based on these studies, it is being concluded that the larger signals for NO x on sensors with Cr 2O 3 electrodes arise primarily due to the poorer oxygen electroreduction ability of Cr 2O 3 as compared to LSFCO.