Lithium Promotes Acetylide Formation on MgO During Methane Coupling Under Non-Oxidative Conditions |
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| Authors: | Seraphine B. X. Y. Zhang Quentin Pessemesse Dr. Zachariah J. Berkson Dr. Alexander P. van Bavel Dr. Andrew D. Horton Dr. Pierre-Adrien Payard Prof. Dr. Christophe Copéret |
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| Affiliation: | 1. Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1–5, 8093 Zürich, Switzerland;2. Université de Lyon, Université Claude Bernard Lyon I, CNRS, INSA, CPE, UMR 5246, ICBMS, 1 rue Victor Grignard, 69622 Lyon, France;3. Shell Global Solutions International B.V., Grasweg 31, 1031 HW Amsterdam, The Netherlands |
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| Abstract: | A prototypical material for the oxidative coupling of methane (OCM) is Li/MgO, for which Li is known to be essential as a dopant to obtain high C2 selectivities. Herein, Li/MgO is demonstrated to be an effective catalyst for non-oxidative coupling of methane (NOCM). Moreover, the presence of Li is shown to favor the formation of magnesium acetylide (MgC2), while pure MgO promotes coke formation as evidenced by solid-state 13C NMR, thus indicating that Li promotes C−C bond formation. Metadynamic simulations of the carbon mobility in MgC2 and Li2C2 at the density functional theory (DFT) level show that carbon easily diffuses as a C2 unit at 1000 °C. These insights suggest that the enhanced C2 selectivity for Li-doped MgO is related to the formation of Li and Mg acetylides. |
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| Keywords: | Active Sites C−H Activation Li-Doped MgO Metal Acetylide Methane Coupling |
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