Acid-Free Synthesis of Mesoporous Silica Using Triblock Copolymer as Template with the Aid of Salt and Alcohol
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- 作者：Shih-Yuan Chen ; Soofin Cheng
- 刊名：Chemistry of Materials
- 出版年：2007
- 出版时间：June 12, 2007
- 年：2007
- 卷：19
- 期：12
- 页码：3041 - 3051
- 全文大小：645K
- 年卷期：v.19,no.12(June 12, 2007)
- ISSN：1520-5002
文摘
Under acid-free conditions using tetraethyl orthosilicate (TEOS) as the silica source and triblockcopolymer P123 as the template, mesoporous silica materials of either ultra-large mesoporous cellularfoam (MCF) or two-dimensional (2D)-hexagonal p6mm pore arrangement were synthesized with the aidof salt and alcohol. The pore structure was varied with the concentrations of P123 and NaCl and thepresence of alcohol in the synthesis solution. The porous network of the resulting MCF structure obtainedin the aqueous solutions containing TEOS, P123, and NaCl was changed from closed window cell toopen window cell when the concentrations of P123 and NaCl were increased. On the other hand, whena proper amount of ethanol was added as cosolvent, mesoporous silica with 2D-hexagonal pore arrangementsimilar to that of SBA-15 and MSU-H was obtained. The resultant materials possessed high surface area(626-896 m2/g), mesopores (6.3-6.6 nm in diameter) of reasonable pore size distribution (2.5-3.0nm), and large porosity (0.91-1.13 cm3/g). On the basis of the 29Si magic angle spinning NMR spectra,the mesoporous materials synthesized under acid-free conditions have better cross-linked silica frameworkthan those prepared in an acidic environment such as SBA-15. The pore ordering was retained even afterboiling the material in water for 72 h. Moreover, the pore size distribution was narrowed down to 1.0-1.7 nm, attributed to the re-organization of the silica framework during the hydrothermal treatment.