Paper Title:
Synthesis and Structural Characterization of SiO2-Al2O3 Xerogels
  Abstract

Low-density xSiO2-(1-x)Al2O3 xerogels with x=0.9, 0.8, 0.7, 0.6 (mole fractions) were prepared by sol-gel and non-supercritical drying. Silica alkogels, which were the framework of binary composite materials, formed from tetraethyl orthosilicate (TEOS) by hydrolytic condensation with a molar ratio of TEOS: H2O: alcohol: hydrochloric acid: ammonia =1: 4: 10: 7.5×10-4: 0.0375. Aluminum hydroxide derived from Al(NO3)3·9H2O and NH4OH acting in the alcohol solution under the condition of catalyst. After filtrating and washing, the precipitation was mixed into silica sols to form SiO2-Al2O3 mixed oxide gels with different silicon and aluminum molar ratio. The structural change and crystallization of the binary xerogels were investigated after heat treatment at 600  for 2 h by the means of X-ray diffraction. Nitrogen adsorption experiment was performed to estimate specific surface area, porous volume and pore size distribution. The structural change of xerogels was observed by FT-IR spectroscopy. The resulting mixed xerogels possess of mesoporous structure which is characteristic of cylindrical pores, high specific surface area of 596-863 m2/g and a relatively narrow pore distribution of 2.8-30 nm. Al2O3 is introduced into the SiO2 phase and some of Al-O-Si bonds form.

  Info
Periodical
Key Engineering Materials (Volumes 336-338)
Edited by
Wei Pan and Jianghong Gong
Pages
2286-2289
DOI
10.4028/www.scientific.net/KEM.336-338.2286
Citation
F. He, X. D. He, Y. Li, "Synthesis and Structural Characterization of SiO2-Al2O3 Xerogels", Key Engineering Materials, Vols. 336-338, pp. 2286-2289, 2007
Online since
April 2007
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$32.00
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