Coordination Environment of Copper Sites in Cu-CHA Zeolite Investigated by Electron Paramagnetic Resonance

By Anita Godiksen, F. N. Stappen, Peter N. R. Vennestrøm, Filippo Giordanino, S. B. Rasmussen, L. Lundegaard, S. Mossin. 2014

189 citations recorded by the source corpus.

Cu-CHA combines high activity for the selective catalytic reduction (SCR) reaction with better hydrothermal stability and selectivity compared to other copper-substituted zeolites. At the same time Cu-CHA offers an opportunity for unraveling the coordination environment of the copper centers since the zeolite framework is very simple with only one crystallographically independent tetrahedral site (T-site). In this study the results of an X-band electron paramagnetic resonance (EPR) investigation of ion-exchanged Cu-CHA zeolite with a Si/Al ratio of 14 ± 1 is presented. Different dehydration treatments and rehydration experiments are performed in situ while monitoring with EPR. The results are compared with recent literature evidence from temperature-programmed reduction, X-ray methods, IR spectroscopic methods, and UV–visible spectroscopy. On the basis of these findings quantitative information is obtained for the different copper positions in dehydrated Cu-CHA. The well-defined copper sites in the six-me...

Subfields: Inorganic Chemistry, Materials Chemistry, Organic Chemistry

View Paper: https://www.semanticscholar.org/paper/79b7051293e8c22dc70cb15392079d0dcb698d53