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Journal Article

Active Sites in Olefin Metathesis over Supported Molybdena Catalysts

MPS-Authors
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Amakawa,  Kazuhiko
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

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Kröhnert,  Jutta
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

/persons/resource/persons22257

Wrabetz,  Sabine
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

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Frank,  Benjamin
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

/persons/resource/persons22071

Schlögl,  Robert
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

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Trunschke,  Annette
Inorganic Chemistry, Fritz Haber Institute, Max Planck Society;

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Fulltext (public)

2180182.pdf
(Any fulltext), 477KB

Supplementary Material (public)

2180182_SI.pdf
(Supplementary material), 138KB

Citation

Amakawa, K., Kröhnert, J., Wrabetz, S., Frank, B., Hemmann, F., Jäger, C., et al. (2015). Active Sites in Olefin Metathesis over Supported Molybdena Catalysts. ChemCatChem, 7(24), 4059-4065. doi:10.1002/cctc.201500725.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0028-2EDB-1
Abstract
Metathesis of propene to ethene and 2-butenes was studied over a series of MoOx/SBA-15 catalysts (molybdenum oxide supported on mesoporous silica SBA-15; Mo loading 2.1~13.3 wt%, apparent Mo surface density 0.2~2.5 nm-2). The catalysts have been prepared by an ion exchange technique. Nitrogen adsorption, 1H-MAS-NMR, Raman, and FTIR spectroscopies were applied to characterize the catalysts. Adsorption of the reactant propene and the probe molecule NH3 was studied by in situ FTIR, microcalorimetry and temperature-programmed desorption. Irrespective of the loading, only ca. 1% of the Mo atoms in the MoOx/SiO2 catalysts transform into active carbene (Mo=CHR) sites catalyzing propene metathesis. Isolated, distorted molybdenum di-oxo species in close vicinity to two silanol groups have been shown to be the precursor of the active site. Targeted active site creation by pretreatment with methanol resulted in an increase in initial catalytic activity by a factor of 800.