Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

Sensors

Andrea Groβ³  Michael Kremling³  Isabella Marr³  David J. Kubinski¹  Jacobus H. Visser¹  Harry L. Tuller² 

[1] Ford Research and Advanced Engineering, Dearborn, MI 48124, USA; E-Mail:;Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; E-Mail:;Zentrum für Energietechnik, Bayreuth Engine Research Center (BERC), Department of Functional Materials, University of Bayreuth, 95440 Bayreuth, Germany; E-Mails:

关键词: NO_x dosimeter;    lean NO_x trap (LNT);    precious metal free NO_x storage catalyst (NSC);    electrical TPD;    accumulating sensing principle;    low ppm-level NO_x detection;    in-situ catalyst loading state monitoring;    ammonia SCR;    three-way catalyst (TWC);   

DOI  :  10.3390/s130404428

来源: mdpi

【 摘 要 】

An impedimetric NO_x dosimeter based on the NO_x sorption material KMnO₄ is proposed. In addition to its application as a low level NO_x dosimeter, KMnO₄ shows potential as a precious metal free lean NO_x trap material (LNT) for NO_x storage catalysts (NSC) enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO₂ exposure can be detected electrically as instantaneous values at 380 °C by progressive NO_x accumulation in the KMnO₄ based sensitive layer. The linear NO_x sensing characteristics are recovered periodically by heating to 650 °C or switching to rich atmospheres. Further insight into the NO_x sorption-dependent conductivity of the KMnO₄-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD). The NO_x loading amount increases proportionally to the NO_x exposure time at sorption temperature. The cumulated NO_x exposure, as well as the corresponding NO_x loading state, can be detected linearly by electrical means in two modes: (1) time-continuously during the sorption interval including NO_x concentration information from the signal derivative or (2) during the short-term thermal NO_x release.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.