A Novel Route toward the Synthesis of High-Quality Large-Pore Periodic Mesoporous Organosilicas

Bao, Xiao Ying; Zhao, Xiaoke; Li, Xu; CHIA, P; Li, Jun

doi:10.1021/jp037342m

Cited by 104 publications

(113 citation statements)

References 42 publications

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“…Some researchers synthesized ordered materials with butanol as co-surfactant or with sodium silicate as silica source at reduced acidities [12][13][14]38], but the pH values of the synthesis solution were still less than 1 with a hydrochloric acid concentration of not less than 0.1 M. The hydronium ions might play essential roles in the template synthesis of SBA-15 because they are involved in the assembly reactions. The hydronium ions are known to catalyze the hydrolysis of siloxane to form silica species such as silica oligomers and silica monomers [39,40], which serve as building units for the construction of mesoporous silica. Furthermore, the micelle of triblock copolymer EO 20-PO 70 EO 20 in water is constituted by a hydrophobic PPO core and a hydrophilic PEO shell, and the hydronium ions lead to protonation of the PEO chains, therefore the PEO shell appears to be positively charged under acidic conditions [23,41], which induces electrostatic interactions with the silica species.…”

Section: Structural Evolution With Synthesis Aciditymentioning

confidence: 99%

Expanding mesoporosity of triblock-copolymer-templated silica under weak synthesis acidity

Tian

et al. 2009

Journal of Colloid and Interface Science

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a b s t r a c tWith initial aging at low temperature for enough time, silicas with large mesoporosity were synthesized using triblock copolymer as template agent under weak acidities. SBA-15 with periodic mesostructure and short mesochannels could be synthesized at pH 2.5-3.0 within weak acidity range, and the surface areas, pore diameters and pore volumes reached up to ca. 1000 m 2 /g, 8.8 nm and 2.0 cm 3 /g, respectively, which were significantly higher than those of the conventional SBA-15 synthesized under strong acidities. Mesoporous silica with wormhole structure and abundant textural porosity was formed at pH $ 3.5. The increased hydrophobic volume of the copolymer micelles at elevated pH values was responsible for the enlargement of mesoporosity in the products. The materials synthesized under weak acidities showed lower hexagonal ordering in comparison to the general SBA-15 synthesized under strong acidities because the decreased hydronium ion concentration induced relatively weaker assembly forces during the synthesis. Nonetheless, the short mesochannels and large pore diameter in the products might be beneficial to some applications in which fast diffusion of molecules is required.

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Section: Structural Evolution With Synthesis Aciditymentioning

confidence: 99%

Expanding mesoporosity of triblock-copolymer-templated silica under weak synthesis acidity

Tian

et al. 2009

Journal of Colloid and Interface Science

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“…Highly ordered PMOs with 2D, 3D hexagonal and cubic Pm3n, Im3m, Fm3m mesophases can be synthesized under strongly basic or acidic conditions based on the electrostatic interaction between the organosilica and the template aggregates. 1,6,[14][15][16][17][18][19][20][21] However, because many organic groups are sensitive to acid or base and the breakage of Si-C bonds will possibly occur under such conditions, 22 …”

Section: Introductionmentioning

confidence: 99%

Highly ordered periodic mesoporous ethanesilica synthesized under neutral conditions

et al. 2005

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Highly ordered mesoporous ethanesilica (MES) with 2D hexagonal structure was synthesized from 1,2-bis(trimethoxysilyl)ethane under neutral conditions for the first time. Divalent salts, such as NiCl 2 , MgCl 2 , ZnCl 2 , ZnSO 4 and Zn(NO 3 ) 2 , were used to help the formation of the ordered mesostructure. The MES samples were characterized by powder X-ray diffraction, nitrogen sorption, transmission electron microscopy, FT-IR, 13 C and 29 Si solid-state NMR and thermal gravimetric analysis. A phase transition from a disordered wormhole-like structure to an ordered P6mm structure was observed upon the addition of inorganic salts. The pore size of the MES decreases from 4.7 to 3.9 nm with increasing content of the inorganic salts. Fluoride was also found to be important for the formation of ordered MES under neutral conditions.

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“…The structure also maintains a periodic pore system that can be tailored to specific needs through the adjustment of the organic spacer R I . A number of PMO's have been generated through this method, using bridging groups such as ethane, methylene, saturated alkyl chains containing methylene groups, benzene, thiophene, ferrocene [29][30][31][32]. The organic functionality of PMO materials can be tuned to suit the application required.…”

Section: Bridged Silesquioxanesmentioning

confidence: 99%

Modification of Mesoporous Silicates for Immobilization of Enzymes

2012

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Mesoporous silicates (MPS) possess ordered pore structures with pore diameters sufficiently large to accommodate a range of enzymes. The successful immobilization of an enzyme on MPS usually requires modification of the surface of MPS to optimize the interactions between the support and the enzyme. Recent developments on the 2 functionalization of MPS for the immobilization of enzymes are described in this review.

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A Novel Route toward the Synthesis of High-Quality Large-Pore Periodic Mesoporous Organosilicas

Cited by 104 publications

References 42 publications

Expanding mesoporosity of triblock-copolymer-templated silica under weak synthesis acidity

Expanding mesoporosity of triblock-copolymer-templated silica under weak synthesis acidity

Highly ordered periodic mesoporous ethanesilica synthesized under neutral conditions

Modification of Mesoporous Silicates for Immobilization of Enzymes

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