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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/28323


    Title: Ordered and Hydrothermally Stable Cubic Periodic Mesoporous Organosilicas with SBA-1 Mesostructures: Synthesis, Characterization, Solid-State NMR Spectroscopy, and DFT Calculations
    Authors: Pan,YC;Wu,HY;Jheng,GL;Tsai,HHG;Kao,HM
    Contributors: 中央大學
    Keywords: MOLECULAR-SCALE PERIODICITY;LARGE-PORE;SILICA SBA-1;MAS NMR;CHEMICAL-SHIFT;HIGH-SPEED;GEMINI SURFACTANTS;ASSISTED SYNTHESIS;ORGANIC GROUPS;CHANNEL WALLS
    Date: 2009
    Issue Date: 2010-06-29 19:46:07 (UTC+8)
    Publisher: 化學研究所
    Abstract: Periodic mesoporous organosilicas (PMOs) based on the cubic SBA-1 mesostructure (Pm3n mesophase) were synthesized by co-condensation of tetraethoxysilane (TECS) and 1,2-bis(triethoxysilyl)ethane (BTEE) under acidic conditions using cetyltriethylammonium bromide (CTEABr) as a structure-directing agent. The ethane-bridged PMO materials thus obtained were characterized by powder X-ray diffraction (XRD), solid-state C-13 and Si-29 NMR spectroscopy, thermogravimetric analysis (TGA), and nitrogen sorption measurements. The maximum BTEE contents that can be incorporated into the pore wall without degrading the Pm3n mesostructure were up to 60% (based on silica). The resulting materials were hydrothermally stable up to 120 h in boiling water with only a slight decrease in their structural properties, whereas the structure of the pure silica counterpart SBA-1 material was completely collapsed after such treatment. The presence of the ethane groups in the mesoporous wall led to a more hydrophobic environment and thus enhancement of hydrothermal stability, as revealed by water adsorption. The combined results of 2D Si-29 {H-1} heteronuclear correlation (HETCOR) NMR and density functional theory calculations suggested that the T-3-T-2-Q(4)-Q(3) motif could be the favorable framework building unit in PMOs.
    Relation: JOURNAL OF PHYSICAL CHEMISTRY C
    Appears in Collections:[Graduate Institute of Chemistry] journal & Dissertation

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