Aluminum distribution and active site locations in the structures of zeolite ZSM-5 catalysts

• 成果类型: Article
• 署名作者: Rzepka, Przemyslaw; Huthwelker, Thomas; Dedecek, Jiri; Tabor, Edyta; Bernauer, Milan; Sklenak, Stepan; Mlekodaj, Kinga; van Bokhoven, Jeroen A.
• 署名单位: Czech Academy of Sciences; J. Heyrovsky Institute of Physical Chemistry of the Czech Academy of Sciences; Swiss Federal Institutes of Technology Domain; ETH Zurich; Swiss Federal Institutes of Technology Domain; Paul Scherrer Institute; Swiss Federal Institutes of Technology Domain; Paul Scherrer Institute; University of Chemistry & Technology, Prague
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-10903
• DOI: 10.1126/science.ads7290
• 发表日期: 2025-04-25
• 页码: 423-428
• 关键词: x-ray-diffraction; al distribution; acid sites; propene oligomerization; chabazite zeolites; reaction pathway; al-27 mas; t-sites; FRAMEWORK; methanol

摘要

Zeolites have exceptional catalytic performance in oil refining and chemical synthesis that can be attributed to their well-defined porous structures that host active sites. This study pinpoints the exact locations of aluminum atoms in ZSM-5 structures-a key zeolite catalyst. Aluminum siting governs catalytic efficiency in acid and redox processes. Anomalous x-ray powder diffraction (AXRPD) at the aluminum K-edge probes the long-range order of aluminum atoms within the ZSM-5 frameworks, precisely quantifying both isolated aluminum atoms and Al(-O-Si-O-)(x)Al sequences (aluminum pairs). Supported by nuclear magnetic resonance studies, AXRPD unambiguously determines the crystallographic organization of aluminum pairs, recognized spectroscopically as alpha, beta, and gamma sites, linking their distribution to superior catalytic activity in propene oligomerization. This combined approach provides essential insights for optimizing zeolite catalysts and enhancing their performance.