| Co-Investigator(Kenkyū-buntansha) |
TAMAKI Jun Kyushu Univ. Grad.School of Eng.Sci.,Research Associate, 大学院・総合理工学研究科, 助手 (10207227)
SHIMIZU Youichi Kyushu Univ. Grad.School of Eng.Sci.,Research Associate, 大学院・総合理工学研究科, 助手 (20192114)
MIURA Norio Kyushu Univ Grad.School of Eng.Sci.,Associate Prof., 大学院・総合理工学研究科, 助教授 (70128099)
|
|---|
| Research Abstract |
Sensing properties of solid electrolyte oxygenic gas sensor were greatly improved by using multi-component auxiliary electrode. 1. The use of a binary nitrate electrode of NaNO_3-Ba(NO_3)_2 for solid electrolyte NO_2 sensor made it possible to stand operation at higher temperature up to 500ﾟC,as well as to suppress the interference of water vapor. An NO_2 sensor using Ba(NO_3)_2 auxiliary electrode and Ba-beta/beta"-alumina was found to show quicker responses and to stand higher temperature operation. A NASICON-based solid electrolyte device fitted with an NaNO_2 auxiliary electrode showed excellent sensing characteristics to NO and NO_2 in air,i.e., the electromotive force (EMF) followed the Nernt's equation for 1 - 800 ppm NO and 0.1 - 200 ppm NO_2 at temperatures of 150-240ﾟC. The response of these sensors were found to be totally independent of coexisting oxygen. 2. A NASICON-based CO_2 sensor was greatly improved in response and water vapor-resistance by using binary carbonate ele
… More
ctrodes of Na_2CO_3-BCO_3(B=Ca,Sr,Ba). These sensors could respond very well to CO_2 in air over a wide temperature range of 270-600ﾟC. The CO_2 sensor was further improved in stability by using Li-based binary carbonate electrodes of Li_2CO_3-BCO_3(B=Ca,Sr,Ba). The sensor responses, EMF, to varying partial pressure of CO_2 were in accordance with a 2-electron reaction of CO_2, while the response to a fixed P_<CO2> was found to be almost independent of partial pressure of O_2 at temperatures above 450ﾟC, while at 305ﾟC and below, it dependent on P_<O2> in a manner similar to a 2- electron reaction of O_2. Thus, two-types of sensing electrode reactions including peroxycarbonate or peroxide were indicated to occur depending on working temperature. 3. Electrochemical cells using MgO-stabilized zirconia tube coated with metal sulphates were found to exhibit fairly good sensing properties to 20-200 ppm SO_2 in air at 650-800ﾟC. SO_x sensor using Li_2SO_4-CaSO_4-SiO_2 auxiliary electrode showed quicker response, 90% response and 90% recovery time to 20 ppm SO_2 at 650ﾟC were 10_s and 7 min, respectively. This sensor exhibits excellent selectivity and good stability in long-term operation. Less
|
