Selective detection of NO by using an amperometric sensor based on stabilized zirconia and oxide electrode

Stabilized zirconia-based devices using oxide electrode (CdCr2O4) were fabricated and examined for selective amperometric detection of NO at high temperature. The CdCr2O4-attached tubular device showed quick and selective response to NO over NO2 at 500 and 550 degrees C, if the potential of sensing electrode was polarized properly at +100 mV vs the reference Pt electrode. The 90% response time of the device to 100 ppm NO was as short as approximate to 20 a at 500 degrees C. The current response was well correlated to the NO concentration in the range of 0-200 ppm. Furthermore, the current response was hardly affected by the presence of the other gases, such as NO2, H-2, CO, CH4, CO2, and water vapor. A compact, plate-type device which required no reference gas was also fabricated and its sensing properties were confirmed to be also rather good. A plausible NO sensing mechanism of the present devices was proposed on the basis of the sensing characteristics obtained. (C) 1999 Elsevier Science B.V. All rights reserved.