首页> 外文会议>Impact of Zeolites and Other Porous Materials on the New Technologies at the Beginning of the New Millennium >Aluminum Incorporation and Interfacial Structures in AlSBA-15 mesoporous solids: double resonance and Optically Pumped Hyperpolarized ~(129)Xe NMR Studies
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Aluminum Incorporation and Interfacial Structures in AlSBA-15 mesoporous solids: double resonance and Optically Pumped Hyperpolarized ~(129)Xe NMR Studies

机译:AlSBA-15介孔固体中的铝结合和界面结构:双共振和光泵超极化〜(129)Xe NMR研究

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Aluminum-incorporated SBA-15 mesoporous materials have been obtained by direct synthesis. The surfactant ― aluminosilicate interaction during synthesis was studied by double resonance NMR and confronted with the structural properties of the materials obtained after calcinations. Continuous-flow laser-polarized ~(129)Xe NMR spectroscopy was applied for the first time to explore the porosity of the AlSBA-15 mesoporous molecular sieves. TRAPDOR experiments firmly established a strong interaction between segments of the PEO block of the surfactant with the silica-alumina framework. ~1H Dipolar Dephasing revealed that the amount of segments rigidified by this interaction increased with the maturation time. The increased rigidity of the surfactant is to be linked with the increased mesoscopic ordering during maturation, resulting in the higher mesoporous surface obtained after calcinations. The invariability of the TRAPDOR effect proved that the strength of the interaction, that is the degree of interpenetration of the organic/inorganic phases remained the same irrespective of maturation time. Together with the dramatic decrease of the microporous volume with maturation time, this established that the origin of the microporosity of AlSBA-15 is to be found in the incomplete hydrolysis of the TEOS precursor itself rather than in the incomplete PEO-aluminosilicate phase separation.
机译:通过直接合成已经获得了铝结合的SBA-15介孔材料。通过双共振NMR研究了合成过程中表面活性剂-铝硅酸盐的相互作用,并面临煅烧后获得的材料的结构特性。首次采用连续流激光偏振〜(129)Xe NMR光谱法研究了AlSBA-15中孔分子筛的孔隙率。 TRAPDOR实验牢固地建立了表面活性剂的PEO嵌段与二氧化硅-氧化铝骨架之间的强相互作用。 〜1H偶极相移表明,这种相互作用导致的链段数量随着成熟时间的增加而增加。表面活性剂增加的刚度将与成熟期间增加的介观有序性联系在一起,从而导致煅烧后获得更高的介孔表面。 TRAPDOR效应的不变性证明,相互作用的强度,即有机/无机相的互穿程度,与成熟时间无关。随着熟化时间的延长,微孔体积急剧减少,这证明了AlSBA-15的微孔起源是在TEOS前体本身的不完全水解中发现的,而不是在PEO-铝硅酸盐相分离不完全的情况下发现的。

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