The Effect of pH of the Aging Solution on Microstructure of Silica/Zirconia Aerogel

Abstract:

ZrO₂ wet gel was prepared using zirconium n-butoxide as precursor and 1,2-propylene oxide (PO) as a gelation agent in sol-gel process. Then, tetraethoxysilane (TEOS) was used to strengthen the wet gel in aging process. Finally, the monolithic silica/zirconia aerogel was obtained by supercritical fluid drying. N₂ adsorption-desorption method, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize microstructure of the aerogel. The influence of pH of the aging solution on microstructure of silica/zirconia aerogel was studied. The results indicate that the particle size distribution of SiO₂/ZrO₂ aerogel was more uniform and less aggregate when aging in acid solution. However, the average pore diameter and particle size of SiO₂/ZrO₂ aerogel was increased by aging in alkaline solution. Aging in alkaline condition was useful for largening the pore size of SiO₂/ZrO₂ aerogel, and the maximum specific surface area and pore volume were obtained at pH=9. Meanwhile, different reactions were produced between the acid/alkaline solution and the hydroxyl of SiO₂/ZrO₂ aerogel, and the ester group/amino group was obtained relatively which can modify the network of aerogel and decrease the shrinkage of aerogel during the supercritical fluid drying.

• Periodical: Key Engineering Materials (Volumes 602-603)
• Pages: 358-362
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.602-603.358
• Online since: March 2014
• Authors: Jian He, Xiao Lei Li*, Hui Ming Ji, Qing Pu Wang
• Keywords: Microstructure, pH of Aging Solution, SiO₂/ZrO₂ Aerogel

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