TiO2-SiO2 compound aerogel and its preparation method

Abstract

The invention provides a TiO2-SiO2 composite aerogel and a preparation method of the TiO2-SiO2 composite aerogel. The Ti / Si molar ratio of the TiO2-SiO2 composite aerogel is ranging from 1:10 to 10:1, the density thereof is 0.1-0.35 g / cm<3>, the porosity thereof is 84-94%, the aperture thereof is 5.0-20.0nm, the pore volume thereof is 1.0-5.0cm<3> / g and the specific surface thereof is 500-1200m<2> / g. The preparation method mainly comprises the steps that modifier consisting of alcohols, silanes and alkanes reagent is used for carrying out the modification and solvent replacing disposal. The TiO2-SiO2 composite aerogel of the invention has the advantages of low density, large specific surface, high pore volume and high porosity; the porosity can achieve 84-94%; the preparation method of the TiO2-SiO2 composite aerogel adopted by the invention adopts cheap and easily gained raw material TiCl4 and industrial water glass and can reduce the production cost; furthermore, the normal-pressure dry-process is convenient and feasible, and suitable for large-scale industrialization production and application.

Description

technical field [0001] The present invention relates to TiO with high pore volume and high specific surface area 2 -SiO 2 A method for preparing a composite airgel by normal-pressure drying. Background technique [0002] Titanium dioxide (TiO 2 ) Photocatalytic materials have the advantages of strong oxidation ability, high photocatalytic activity, good chemical and optical stability, etc., and have broad application prospects in solar cells, organic pollutant treatment, sterilization and other environmental protection fields. Especially in recent years, nano-TiO 2 People pay more and more attention to the research and application in environmental protection fields such as air purification and water purification. Like other catalytic materials, TiO 2 Photocatalytic materials need to have a large specific surface area; in addition, the porous structure can endow the material with high adsorption, and the synergistic effect of adsorption / photocatalysis can effectively eli...

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Problems solved by technology

Using butyl titanate and silica sol as raw materials, a relatively complete gel network structure is formed by adding formamide as a drying control chemical additive, and the wet gel is soaked in ethanol solution of tetraethyl orthosilicate and replaced by a low surface tension solvent And graded aging and drying steps, can achieve bulk TiO 2 -SiO 2 Preparation of composite airgel by non-supercritical drying; the resulting TiO 2 -SiO 2 Airgel apparent density is about 0.4~0.9g / cm 3 , the porosity is about 80%~95%, and the specific surface area is 300~400m 2 / g, the pore volume is 1~2cm 3 Between / g (Chemical Journal of Chinese Universities, 2004, 25 (2): 325-329; Journal of Tongji University (Natural Science Edition), 2005, 33 (8): 1078-1082), this process is due to the use of low surface tension The absolute ethanol solution is used to repeatedly soak the gel to replace the water in the gel, so it is very time-consuming, and there is a shortcoming of incomplete replacement, so the obtained TiO 2 -SiO 2 The pore volume and specific surface area of ​​airgel are not very high

In addition, more expensive titanium alkoxide and silicon alkoxide are used to prepare TiO 2 -SiO 2 The precursor of airgel, the preparation cost is relatively high, which is not conducive to TiO 2 -SiO 2 Large-scale production of airgel

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