HERFD-XANES and XES as complementary operando tools for monitoring the structure of Cu-based zeolite catalysts during NOx-removal by ammonia SCR

16th International Conference on X-ray Absorption Fine Structure

Günter, T.^1 ; Doronkin, D.E.^1,2 ; Carvalho, H.W.P.^1,3 ; Casapu, M.^1 ; Grunwaldt, J.-D.^1,2

Institute for Chemical Technology and Polymer Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, Karlsruhe

D-76131, Germany^1

Institute of Catalysis Research and Technology, KIT, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen

D-76344, Germany^2

Centro de Energia Nuclear Na Agricultura, Av. Centenário, No 303, Piracicaba - São Paulo

13400-970, Brazil^3

关键词: Catalyst optimization;    Catalytic reactions;    Cu based zeolites;    Cu-zeolite catalysts;    High-energy resolution;    Spatially resolved;    Structural information;    X ray emission spectroscopy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012071/pdf
DOI  :  10.1088/1742-6596/712/1/012071

来源: IOP

【 摘 要 】

In this article, we demonstrate the potential of hard X-ray techniques to characterize catalysts under working conditions. Operando high energy resolution fluorescence detected (HERFD) XANES and valence to core (vtc) X-ray emission spectroscopy (XES) have been used in a spatially-resolved manner to study Cu-zeolite catalysts during the standard-SCR reaction and related model conditions. The results show a gradient in Cu oxidation state and coordination along the catalyst bed as the reactants are consumed. Vtc-XES gives complementary information on the direct adsorption of ammonia at the Cu sites. The structural information on the catalyst shows the suitability of X-ray techniques to understand catalytic reactions and to facilitate catalyst optimization.