Berlin 2001 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 19: Poster: New Methods, Thin Polymer Films, Monolayers

CPP 19.31: Poster

Donnerstag, 5. April 2001, 12:30–15:00, AT1

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

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 µs 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