The X-ray absorption near edge structure (XANES) and X-ray emission spectroscopy (XES) features were modeled from first principles to aid in identification of reactants, intermediates and products at the active sites in zeolite based catalysts. The models show that the intensities of the XANES spectral features are sensitive to the Cu oxidation state, the number of solvating species (NH<sub>3</sub> or H<sub>2</sub>O), and the coordination environment around the Cu (Figure 1). However, it is found that XANES spectral features are independent on the Cu-ligand bond length, the ligands and the zeolite type. As an complementary technique to XANES, XES is a sensitive probe of the nature of the ligands. It is possible to distinguish Cu-N and Cu-O bonds with this technique, as displayed in Figure 2. Overall, our careful analysis of the XANES and XES features of exchanged ions can help us gain further insights into the synchrotron-based experimental results, which could lead to a new understanding of the underlying reaction mechanisms.

Environmental sensitivity of spectroscopic properties for Cu ions in Cu-SSZ-13: XANES and XES studies from first principles

254th National Meeting (2017)

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