物理化学学报 >> 2010, Vol. 26 >> Issue (04): 1171-1176.doi: 10.3866/PKU.WHXB20100445

材料物理化学 上一篇    下一篇

真空冷冻干燥制备高比表面积纳米氧化铝

刘祥志, 朴玲钰, 毛立娟, 郝士杰, 杨磊, 鞠思婷   

  1. 国家纳米科学中心, 北京 100190; 天津大学化工学院催化科学与工程系, 天津 300072
  • 收稿日期:2009-08-27 修回日期:2009-12-23 发布日期:2010-04-02
  • 通讯作者: 朴玲钰 E-mail:piaoly@nanoctr.cn

Preparation of High Specific Surface Area Nano-Alumina by Vacuum Freeze Drying

LIU Xiang-Zhi, PIAO Ling-Yu, MAO Li-Juan, HAO Shi-Jie, YANG Lei, JU Si-Ting   

  1. The National Center for Nanoscience and Technology of China, Beijing 100190, P. R. China; Department of Catalysis Science and Technology, School of Chemical Engineering and Technology, Tianjin University , Tianjin 300072, P. R. China
  • Received:2009-08-27 Revised:2009-12-23 Published:2010-04-02
  • Contact: PIAO Ling-Yu E-mail:piaoly@nanoctr.cn

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摘要：

采用真空冷冻干燥技术结合反相微乳液法, 于环己烷/聚乙二醇辛基苯基醚(曲拉通X-100)-十六烷基三甲基溴化铵(CTAB)/正丁醇/水溶液体系中, 合成了纳米Al2O3粉体. 采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)及比表面积与孔隙度分析仪对产物的形貌、结构、比表面积、孔容与孔径进行了表征. 经过煅烧, 该纳米Al2O3比表面积约550.0 m2·g-1(随反应参数不同而变化), 属γ-Al2O3晶型, 粒径均匀, 颗粒直径小于10.0 nm. 考察了不同的干燥方式(电热鼓风干燥、普通真空干燥、真空冷冻干燥)以及真空冷冻干燥过程中主要参数对产物比表面积、孔容、平均孔径等物理性质的影响. 结果表明, 采用真空冷冻干燥法制备的纳米Al2O3的比表面积和孔容远高于采用另外两种干燥方式制备的纳米Al2O3. 采用真空冷冻干燥法制备纳米Al2O3时, 降温速率、预冻时间、冻干时间等参数对最终制备的产物比表面积与孔结构有显著影响.

关键词: 真空冷冻干燥, 反相微乳液, 纳米Al2O3, 比表面积, 孔容

Abstract:

Nano-alumina powders were prepared by vacuum freeze drying combined with reverse microemulsion method. The reverse microemulsion system consisted of cyclohexane/polyethylene glycol octylphenyl ether (Triton X-100)-hexadecyl trimethyl ammonium bromide (CTAB)/n-butylalcohol/water. The morphology, structure, specific surface area, pore volume, and pore size of the alumina nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and specific surface area analysis. The specific surface area of the alumina nanoparticles was about 550.0 m2·g-1 (changed with different reaction parameters) and the crystal structure was γ-Al2O3. The particle size was very uniform and smaller than 10.0 nm. The influence of different drying methods (normal hot-gas drying, normal vacuumdrying, vacuumfreeze drying) and the main parameters of vacuum freeze drying on the physical properties of the product were studied. Results showed that the nano-alumina powders obtained by vacuum freeze drying had much higher specific surface area and pore volume than that obtained by the two other drying methods. The specific surface area and pore structure of the nano-alumina were affected by the freezing rate, pre-freezing time, and drying time in the vacuumfreeze drying process.

Key words: Vacuumfreeze-drying, Reverse microemulsion, Nano-Al2O3, Specific surface area, Pore volume