EXAFS study of germanium-rich MFI-type zeolites

✍ Scribed by M.H. Tuilier; A. Lopez; J.L. Guth; H. Kessler

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 323 KB
• Volume: 11
• Category: Article
• ISSN: 0144-2449
• DOI: 10.1016/s0144-2449(05)80168-x

✦ Synopsis

Two MFI-type zeolite samples containing 8.38 and 16.2 Ge atoms per 96 TOz (T = Si, Ge) were studied by Ge-K-edge X-ray absorption spectroscopy in the as-synthesized state with the (C3H7)4N+ template occluded and in the calcined form. XANES and EXAFS analysis proves the fourfold coordination of Ge in the samples and, hence, its incorporation into the framework. The Ge-0 bond distance which is very close to that in quartz-type Ge02 for the as-synthesized samples, 1.75 + 0.02 A and 1.74 f 0.02 8, for samples 1 and 2, respectively, is shortened to 1.71 + 0.02 A and 1.72 + 0.02 8, after calcination. The structural disorder around germanium is found to be lowered after such a treatment.