Modeling of EPR Parameters for Cu(II): Application to the Selective Reduction of NOx Catalyzed by Cu-Zeolites
2018
Online
Elektronische Ressource
[EN] We present a combined theoretical-experimental study aiming to provide information about the location and coordination environment of the Cu2+ species involved in the selective reduction of NOx with NH3 catalyzed by Cu-zeolites. From the experimental side, we show and discuss the EPR spectra of the three molecular sieves most widely used as catalysts for the NH3-SCR-NOx reaction, namely Cu-SSZ-13, Cu-SAPO-34 and Cu-ZSM-5 both in their hydrated state and after dehydration. Then, we investigate the EPR spectra of Cu-SSZ-13 and Cu-SAPO-34 under the following conditions: (i) after NH3 adsorption, (ii) after NO addition, and (iii) in the presence of a NO/O-2 mixture. As regards the theoretical part, an exhaustive computational study has been performed that includes geometry optimization and calculation of the EPR parameters of all the relevant systems involved in the NH3-SCR-NOx reaction. The influence of local geometry and Al/Si distribution in the zeolite framework on the EPR parameters and the most probable location of Cu2+ in each material are analyzed, and assignations of the EPR signals obtained under different reaction conditions are discussed.
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Modeling of EPR Parameters for Cu(II): Application to the Selective Reduction of NOx Catalyzed by Cu-Zeolites
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Veröffentlichung: | 2018 |
Medientyp: | Elektronische Ressource |
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