Details

Autor(en) / Beteiligte

• Kim, Sungmin
• Lee, Mal-Soon
• Camaioni, Donald M.
• Gutiérrez, Oliver Y.
• Glezakou, Vassiliki-Alexandra
• Govind, Niranjan
• Huthwelker, Thomas
• Zhao, Ruixue
• Rousseau, Roger
• Fulton, John L.
• Lercher, Johannes A.

Titel

Self-Organization of 1‑Propanol at H‑ZSM‑5 Brønsted Acid Sites

Ist Teil von

• JACS Au, 2023-09, Vol.3 (9), p.2487-2497

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2023

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• In situ Al K-edge X-ray absorption near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS) spectroscopy in conjunction with ab initio molecular dynamics (AIMD) simulations show that adsorption of 1-propanol alters the structure of the Brønsted acid site through changes in the associated aluminum–oxygen tetrahedron in zeolite H-MFI. The decreasing intensity of the pre-edge signal of the in situ Al K-edge XANES spectra with increasing 1-propanol coverage shows that Al T-sites become more symmetric as the sorbed alcohol molecules form monomers, dimers, and trimers. The adsorption of monomeric 1-propanol on Brønsted acid sites reduces the distortion of the associated Al T-site, shortens the Al–O distance, and causes the formation of a Zundel-like structure. With dimeric and trimeric alcohol clusters, the zeolite proton is fully transferred to the alcohols and the aluminum–oxygen tetrahedron becomes fully symmetric. The subtle changes in Al–K-edge XANES in the presence of sorbate structures, with the use of theory, are used to probe the local zeolite structures and provide a basis to predict the population and chemical state of the sorbed species.