P2.8.5 Sensing of NO, NO2, and NH3 with Zeolite-Based Impedimetric Gas Sensors

14th International Meeting on Chemical Sensors - IMCS 2012
2012-05-20 - 2012-05-23
Nürnberg/Nuremberg, Germany
P2.8 Sensors Based on New Materials
I. Marr, A. Nützel, D. Schönauer-Kamin, R. Moos - Dept. of Functional Materials, University of Bayreuth (Germany)
1660 - 1663


In this study, the suitability of zeolites for two different sensor principles is investigated. Zeolites can change their electrical properties with the sorption of gas molecules in their microporous network structure. Therefore, they are potential materials for impedimetric gas sensors. The screened zeolites H-ZSM-5, Fe-ZSM-5, Pt-loaded H-ZSM-5, and Pt-loaded Fe-ZSM-5 are tested for their sensitivity towards NO, NO2, and NH3 at varying temperatures. The two different sensor principles are considered: the integrating- or accumulating-type sensing behavior at low temperatures and a conventional gas sensor behavior at high temperatures. At high temperatures, only the expected response towards NH3 occurs, whereas at low temperatures a cross effect towards NOx could be observed for H-ZSM-5 and Fe-ZSM-5. The sensor behavior seems to be an integrating one at 200 °C for NO and NO2. By inserting elementary platinum the sensitivity towards NO and NO2 was eliminated due to a higher catalytic activity of the Pt-loaded zeolite. At temperatures of 400 °C and 500 °C, the Ptloaded zeolites show no response even not towards NH3.