Design of Heterogeneous Catalysts on the Molecular Scale: A Unique Way to High Quality Li-doped MgO
EUROMAT 2009 European Congress and Exhibition on Advanced Materials and Processes, Glasgow, United Kingdom, 7 - 10 September 2009, pp.20, (Full Text)
- Publication Type: Conference Paper / Full Text
- City: Glasgow
- Country: United Kingdom
- Page Numbers: pp.20
- Akdeniz University Affiliated: Yes
Abstract
Li doped MgO, which was described the first time in 1985 by Lunsford et al., is a promising and well studied catalyst for the oxidative coupling of methane.[1] The activity of the catalyst strongly depends on the contribution of Li-ions in the MgO lattice.[2] Metalorganic Single Source Precursors contain all metals needed for the heterogenous catalyst on a molecular scale and therefore, lead to materials with a high dispersion of the dopant in the host lattice. Furthermore, they can be decomposed at relatively low temperatures. Thus, we carried out the preparation and decomposition of the first single source precursors for Li doped MgO.
The heterobimetallic alkoxides [(MeMgOR)3(LiOR)(thf)] (R= iPr, tBu, CyHex) were prepared from the reaction of [MeMgOR]4 with LiOR in tetrahydrofurane. Thermal decomposition of mixtures of [(MeMgOR)3(LiOR)(thf)] with [MeMgOR]4 lead to Li doped MgO with different Li amounts. All decompositions take place at temperatures less than 300°C. The particles obtained are nanocrystalline with sizes between 11 and 26 nm depending on the Li amount. The samples were characterized by TGA, PXRD, TEM, EDX, elemental analysis, nitrogen adsorbtion, PL- and Raman spectroscopy.
[1] a) T. Ito, J. H. Lunsford, Nature 1985, 314, 721. b) T. Ito, J. X. Wang, C. H. Lin, J. H. Lunsford, J. Am. Chem. Soc. 1985, 107, 5062.
[2] T. Ito, J. X. Wang, C. H. Lin, J. H. Lunsford, J. Am. Chem. Soc. 1985, 107, 5062.