GS3.5 - A Gas Sensing Approach to Gain Insight into the Mechanism of DeNOx-SCR over Fe-ZSM-5 Catalysts
- 17th International Meeting on Chemical Sensors - IMCS 2018
2018-07-15 - 2018-07-19
- Gas Sensors 3
- V. Rizzotto, U. Simon - RWTH Aachen University, Aachen (Germany), P. Chen - South China University of Technology, Guangzhou (China), G. Hagen, R. Moos - University of Bayreuth, Bayreuth (Germany)
- 134 - 135
In order to meet the legislative emission requirements for NOx emission, selective catalytic reduction (DeNOx-SCR) catalysts, in particular zeolites, are used. To improve their catalytic performance, an in-depth understanding of the reaction mechanisms is required based on an analysis of the physicochemical properties, preferably in situ. We introduce a setup combining impedance spectroscopy (IS) and infrared spectroscopy in diffuse reflection mode (DRIFT) for in situ measurements on zeolites under SCR-related conditions. By means of this gas sensing approach, we observed the formation of ammonium ion (NH4+) intermediates resulting from the interaction of NO and NH3 on Fe-ZSM-5 catalysts. The formed NH4+ intermediates, indicating the activation of NO in the presence of adsorbed NH3, were found to correlate to the NH3−SCR activity of Fe-ZSM-5 catalysts at low temperatures. These findings, which are not easily achievable by conventional methods, provide new and important perspectives to understand mechanistically the NH3−SCR reaction over Fe-zeolite catalysts.