Mesoporous SnO2-SiO2 and Sn-silica-carbon nanocomposites by novel non-hydrolytic templated sol-gel synthesis

0462668 - ÚACH 2017 RIV GB eng J - Journal Article
Škoda, D. - Stýskalík, A. - Moravec, Z. - Bezdička, Petr - Buršík, Jiří - Mutin, P. H. - Pinkas, J.
Mesoporous SnO2-SiO2 and Sn-silica-carbon nanocomposites by novel non-hydrolytic templated sol-gel synthesis.
RSC Advances. Roč. 6, č. 73 (2016), s. 68739-68747. E-ISSN 2046-2069
R&D Projects: GA MŠMT(CZ) LQ1601
Institutional support: RVO:61388980 ; RVO:68081723
Keywords : Lewis-acid catalysts * Tin oxide nanoparticles * Twin polymerization
Subject RIV: CA - Inorganic Chemistry; CF - Physical ; Theoretical Chemistry (UFM-A)
Impact factor: 3.108, year: 2016

A novel non-hydrolytic sol-gel (NHSG) synthesis of mesoporous tin silicate xerogels is presented. The polycondensation between silicon tetraacetate, Si(OAc)(4), and tetrakis(diethylamido)tin, Sn(NEt2)(4), resulting in acetamide elimination leads to tin silicate xerogels containing Si-O-Sn linkages. The addition of Pluronic P123 or F127 templates provides homogeneous stiff gels that are, after template removal by calcination at 500 degrees C in air, converted to stable mesoporous silica xerogels with large surface areas (476 m(2) g(-1)) and dispersed SnO2 nanoparticles (6-7 nm). Heat treatment of the as-prepared tin silicate gels in an inert N-2 atmosphere leads to reduction and transformation to Sn nanoparticles (70-150 nm) embedded in a silica-carbon matrix. The composition and morphology of the xerogels, volatile reaction byproducts, and thermal transformations were followed by elemental analyses, IR spectroscopy, thermal analysis TG-DSC, nitrogen adsorption measurements, solid-state NMR spectroscopy, DRUV-vis spectroscopy, electron microscopy, and HT powder XRD. The SnO2-SiO2 xerogels were tested as potential catalysts for aminolysis of styrene oxide with aniline and for the Meerwein-Ponndorf-Verley reduction of 4-tert-butylcyclohexanone. The resulting reaction systems displayed good activity and selectivity.
Permanent Link: http://hdl.handle.net/11104/0262060