The X-ray absorption near edge structure (XANES) [1-3] and X-ray emission spectroscopy (XES) features [4] of Cu-SSZ-13 were modeled from first principles to aid in the 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 a 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 [4]. 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 cations in Cu-SSZ-13: XANES and XES studies from first principles

2019 Spring National Meeting

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