Hamburg 2001 – wissenschaftliches Programm

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M: Metallphysik

M 33: Postersitzung

M 33.35: Poster

Donnerstag, 29. März 2001, 15:15–19:00, Foyer S4, CCH

Solid state NMR/ NQR spectroscopic investigations of Cu-ZnO catalysts — •Annegrit Rabis, M. Baenitz, R. Michalak, and F. Steglich — Max-Planck-Institute for Chemical Physics of Solids Dresden, Nöthnitzer Str. 40, D-01187 Dresden

New nanostructured catalysts were analyzed using solid state NMR/ NQR spectroscopy within the framework of a project about No-dqcopper based catalysts for ’on-board’ production of hydrogen from methanolNo-dq. All NMR active nuclei (¹⁷O, ⁶³Cu, ⁶⁵Cu, ⁶⁷Zn) that are present in the material can be used for NMR under static and under MAS conditions. First investigations were focused on a conventional calcinated non-activated Cu-ZnO catalyst. The chemical shift of -2384 ppm points towards a higher valency of Cu as it has been found for HTSC compounds (1). The very short T₁ relaxation times in s range shows a high paramagnetic amount in the sample. The low natural abundance of ¹⁷O makes very long experimental times necessary for reaching an acceptable S/N ratio. From the spectrum, we derive several different oxygen positions in the catalyst. The observations of ⁶⁷Zn would also provide structural information. Therefore, we have to design a Zn-free probehead to realize ⁶⁷Zn NMR. In conclusion, it is shown that NMR (⁶³Cu, ¹⁷O) investigations can be performed on Cu-ZnO catalysts and that the spectra yield local structural information.
(1) A. Gippius et al. Phys. Rev. B 1999, 59, 654