Li/MgO Catalysts Doped with Alio‐valent Ions. Part I: Structure, Composition, and Catalytic Properties

Doping of Li/MgO with additional metal ions is suggested leading to an improved system with respect to the catalytic performance and stability when used for oxidative coupling of methane. We used Gd and Fe as dopants and characterized the resulting materials, showing that Fe seems to be completely a...

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Bibliographic Details
Published in:ChemCatChem 2017-09, Vol.9 (18), p.3583-3596
Main Authors: Arndt, Sebastian, Simon, Ulla, Kiefer, Klaus, Otremba, Torsten, Siemensmeyer, Konrad, Wollgarten, Markus, Berthold, Almuth, Schmidt, Franziska, Görke, Oliver, Schomäcker, Reinhard, Dinse, Klaus‐Peter
Format: Article
Language:English
Subjects:
alio-valent doping
Catalysis
charge-compensating defects
Deactivation
lithium
Magnesium oxide
methane
oxidative coupling
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Summary:Doping of Li/MgO with additional metal ions is suggested leading to an improved system with respect to the catalytic performance and stability when used for oxidative coupling of methane. We used Gd and Fe as dopants and characterized the resulting materials, showing that Fe seems to be completely and Gd partly incorporated into the MgO lattice. The catalytic performance is improved in most cases, but all materials still suffer from severe deactivation. A loss of Li is observed when being used under reaction conditions, but this Li loss is retarded for Fe‐Li/MgO as compared to undoped Li/MgO. Revealing the local topology: Stabilization of Li:MgO catalysts used for oxidative coupling of methane by doping with alio‐valent transition metal (TM) or rare‐earth (RE) 3+ ions is anticipated because of attractive Coulomb interaction of adjacent Li+/TM3+ or Li+/RE3+ pairs. The prediction of the formation of correlated pairs is verified by observing the loss of local symmetry in the MgO matrix by using 2D EPR.
ISSN:1867-3880
1867-3899
DOI:10.1002/cctc.201700611