Effect of Heat-Treatment on the Microstructure and Properties of SiO₂-TiO₂ Aerogels Synthesized via Supercritical Drying

Abstract:

Monolithic SiO₂-TiO₂ aerogels were prepared via supercritical drying using tetraethoxysilane and tetrabutyltitanate as precursors and ethanol as solvent. Influence of the heat-treatment on the microstructure and properties of SiO₂-TiO₂ aerogels were investigated in detail. The results showed that the as-prepared SiO₂-TiO₂ aerogels had low densities, high specific surface areas, small average pore diameters, and three-dimensional nanoporous structures. The anatase TiO₂ phase of SiO₂-TiO₂ aerogels could form during supercritical drying process, and the transition to rutile TiO₂ phase occurred after experiencing 1200°C for 2 h. SiO₂-TiO₂ aerogels containing 30 wt% TiO₂ (ST3) still presented relatively high specific surface area of 451 m²/g even they undergo the treatment of 1000°C for 2 h. And the SEM images indicated that the agglomerated particles derived from ST3 appeared gradually to some extent. The glassy luster of ST3 heat-treated at 1200°C for 2 h illuminates SiO₂ started to vitrify. Besides, the thermal conductivity of ST3 at room temperature is up to 0.03257 W·m^-1·K^-1.

• Periodical: Materials Science Forum (Volume 848)
• Pages: 770-776
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.848.770
• Online since: March 2016
• Authors: Yong Gang Jiang*, Yan Qing Qin, Jun Zong Feng, Jian Feng, Lin Xu
• Keywords: Crystal Transformation, SiO₂-TiO₂ Aerogel, Specific Surface Area, Supercritical Drying, Thermal Conductivity

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