A Highly Ordered Mesoporous Aluminosilicate, CMI‐10, with a Si/Al Ratio of One

Abstract

A facile and unique but versatile approach for the synthesis of highly organized mesoporous mixed‐element oxide materials with defined structure, high heteroatom content, and stable active sites is presented (see figure). Because of the high homogeneity of the Al sites, the controlled immobilization of (bio)molecules and nanoparticles and the controlled growth of nanowires with relevant new properties may be possible.

Synthesis of Al‐Containing Spherical Mesocellular Silica Foams with Different Pore Sizes and Their Applications as Catalyst Supports for Hydrodesulfurization of Dibenzothiophene

“…Twoo bviously intense peaks centered at % 54 and 0ppm are observed for all samples, suggesting the existence of both tetrahedral (four-coordinated) and octahedral (six-coordinated) aluminums tructuralu nits. [31,45] In addition, as with previous reports, [31,45] ab road weaks ignal at % 33 ppm assigned to the pentahedral (five-coordinated) aluminums ites is observed. The detection of four-coordinated aluminums peciesi ndicates that the aluminums peciesh ave successfully been incorporated into the pure silicon framework.…”

Multiple Functionalization of Mesoporous Silica in One‐Pot: Direct Synthesis of Aluminum‐Containing Plugged SBA‐15 from Aqueous Nitrate Solutions

“…In general, the homogeneity of the Si-O-Al linkages and tetrahedral aluminum sites at a molecular level are very important in catalysis for enhanced activity, selectivity, and stability. [25] As expected, the activity of the porous host is improved when alumina is incorporated into the mesoporous silica by this direct synthesis method, as demonstrated in the catalytic decomposition of isopropyl alcohol used as a probe reaction. Figure 11 discloses that siliceous SBA-15 is inactive for the de-…”

“…A so-called one-step synthesis of the aluminum-incorporated SBA mesoporous molecular sieves under weak conditions at pH 1.5 was reported by Yue et al in 1999 [20] and the produced materials were later used in the cumene cracking reaction. [21] However, use of this method required the mixture of organic aluminium tri-tert-butoxide and the silica source tetraethylorthosilicate (TEOS) to be pre-hydrolyzed for more than 3 h. [20] Many other works, such as those that use the 'pH-adjusting' method, [22,23] premix the liquid organic Al source and TEOS, [24] employ a single silicon and aluminum source, [25] semicrystallize the framework [26] or use zeolite units to modify the wall of SBA-15, [27] and monitor the crystallization process of a zeolite structure on SBA-15 mesopore walls, [14] have also been reported to develop the direct synthesis of aluminumcontaining mesoporous materials. Nevertheless, the direct synthesis of Al-SBA-15 is difficult because, under strongly acidic conditions of preparation of siliceous SBA-15 (pH < 0), free aluminum species such as Al 3+ only exist in cationic form and thus cannot enter the framework of SBA-15 by conventional synthesis.…”

Hierarchically structured meso-macroporous aluminosilicates with high tetrahedral aluminium content in acid catalysed esterification of fatty acids

“…These molecules, constructed from a preformed M-O-Si linkages, are able, under controlled hydrolysis and condensation reactions, to form unequalled chemically homogeneous metallosilicate materials. An Al-Si ester type precursor which already contains an Al-O-Si linkage, the di-sec-butoxyaluminoxytriethoxysilane (sec-BuO) 2 Al-O-Si(OEt) 3 has been used in pioneer works [60][61][62][63]. More importantly, this singlesource molecular precursor possesses, in addition to the preformed Al-O-Si bond, two alkoxide functionalities that are able to undergo fast hydrolysis and polycondensation reactions, rendering possible the auto-generation of a hierarchical meso-macroporosity with unmatched chemical homogeneity, thus, introducing unprecedented acid-base properties with a totally controlled stoechiometry and improved diffusion properties.…”