Preparation and Thermal Stability of Porous Silica-based Monoliths

doi:10.3724/SP.J.1077.2011.00949

Abstract

Abstract: Porous monoliths with high porosity and improved high temperature stability are required in heat insulation. Mesoporous SiO₂ powder was synthesized from tetraethyl orthosilicate using oil-in-water microemulsions composed of non-ionic surfactant P123 and 1,3,5-trimethylbenzene as template. Porous SiO₂ monoliths were prepared from the mesoporous SiO₂ powder by dry pressing followed by sintering. Porous SiO₂/Al₂O₃monoliths and SiO₂/TiO₂ monoliths were prepared from mesoporous SiO₂ powders coated with boehmite Sol and titania Sol respectively. XRD, SEM, TEM, N2 adsorption and Archimedes method were employed to characterize the powders and the monoliths. The thermal stability of the monoliths was studied. The porosity of the silica-based monoliths sintered at 600-700℃ is about 74%?76%. Compared with SiO₂ monolith, porous SiO₂/Al₂O₃monolith has much better thermal stability at 800-1000℃ and porous SiO₂/TiO₂ monolith has an improved thermal stability at 800-900℃. It is indicated that alumina coating on porous silica particle surface can improve the high temperature stability of SiO₂/Al₂O₃ monolith.

Key words: porous monolith, mesoporous, silica, thermal stability, alumina

CLC Number:

TQ174

ZHANG Li-Jie, GU Jing-Hua, YAO Hong-Ying, ZHANG Yue. Preparation and Thermal Stability of Porous Silica-based Monoliths[J]. Journal of Inorganic Materials, 2011, 26(9): 949-954.

References

[1] Ping E W, Wallace R, Pierson J, et al. Highly dispersed palladium nanoparticles on ultra-porous silica mesocellular foam for the catalytic decarboxylation of stearic acid. Microporous and Mesoporous Materials, 2010, 132(1/2): 174-180.

[2] Han Y, Lee S S, Ying J Y. Spherical siliceous mesocellular foam particles for high-speed size exclusion chromatography. Chem. Mater., 2007, 19(9): 2292-2298.

[3] Zhang F Z, Takeaki K, Masayoshi F J, et al. Gelcasting fabrication of porous ceramics using a continuous process. Journal of the European Ceramic Society, 2006, 26(4/5): 67-71.

[4] 邓蔚, 钱立军. 纳米孔硅质绝热材料. 宇航材料工艺, 2002 , 32(1): 1-7.

[5] 罗森诺W M. 传热学基础手册. 北京: 科学出版社, 1992: 304-341.

[6] Jones S M. Aerogel: space exploration applications. J. Sol-Gel Sci. Technol., 2006, 40(2/3): 351-357.

[7] Schmidt-Winkel P, Zhao D Y, Stucky G D, et al. Mesocellular siliceous foams with uniformly sized cells and windows. J. Am. Chem. Soc., 1999, 121(1): 254-255.

[8] Schmidt-Winkel P, Lukens W W, Yang P D, et al. Microemulsion templating of siliceous mesostructured cellular foams with well-defined ultralarge mesopores. Chem. Mater., 2000, 12(3): 686-696.

[9] 冷映丽, 沈晓东, 崔升, 等. 不同制备方法对TiO2-SiO2复合气凝胶结构的影响. 化工新型材料, 2008, 36(8): 57-58.

[10] 武纬, 冯坚, 张长瑞. Al2O3-SiO2气凝胶的制备及性能研究. 材料导报, 2008, 22(S3): 349-351.

[11] Aravind P R, Mukundan P, Krishna P, et al. Mesoporous silica- alumina aerogels with high thermal pore stability through hybrid Sol-Gel route followed by subcritical drying. Microporous and Mesoporous Materials, 2006, 96(1/2/3): 14-20.

[12] 吴建锋, 徐晓虹, 张欣. 以硝酸铝为原料制备铝溶胶的研究. 陶瓷学报, 2007, 28(3): 155-159.

[13] 王英锋, 李雪, 刘云义. 溶胶-凝胶法制备二氧化钛溶胶. 合成化学, 2008, 16(6): 705-708.

[14] 李明月, 周健儿, 马光华. 溶胶-凝胶法制备Al2O3纳米粉. 中国陶瓷, 2002, 38(5): 4-6.

[15] Yang J, Zhang J, Zhu L W, et al. Synthesis of nano titania particles embedded in mesoporous SBA-15: characterization and photocatalytic activity. Journal of Hazardous Materials, 2006, 137(2): 952-958.