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EUROMAT 2009 European Congress and Exhibition on Advanced Materials and Processes, Glasgow, United Kingdom, 7 October - 10 September 2009, pp.19, (Full Text)
Due to its remarkable material properties MgO is one of the most intensively investigated oxides until today. In particular for catalysis[1-3] it is highly desirable to get at low temperatures a controlled access to high quality MgO nanoparticles with tunable defects.
We have investigated the synthesis of nanocrystalline MgO by solid-state thermolysis of the molecular single source precursors [MeMgOR]4 (R=iPr, tBu, CyHex) and Me6Mg7(OR)8 (Et, Pr, Bu). These precursors are easily available by acid base reaction between Me2Mg and alcohols. The decomposition conditions have been varied (heating rate, tempering time, oxygen amount) and the structure and purity of the obtained samples were analyzed by different analytical techniques (TGA, PXRD, TEM, EDX, elemental analysis and nitrogen adsorbtion). The decomposition of all alkoxides to pure nanocrystalline MgO takes place at less than 300 °C. The particle size varies between 8.7 and 15.4 nm depending on the heating rates, tempering times and utilized single source precursors. Surface defects of the samples have been studied by photoluminescence spectroscopy. The ratio of different surface ions with reduced coordination strongly depends on the decomposition conditions, in particular the heating rate and tempering time.
[1] D. J. Driscoll, W. Martir, J. X. Wang, J. H. Lunsford, J. Am. Chem. Soc. 1985, 107, 58.
[2] H. Tsuji, H. Hattori, Catalysis Today 2006, 116, 239.
[3] G. Szöllösi, M. Bartók, Appl. Cat. A: General 1998, 263.