蒲公英状分级结构γ-Al_2O_3颗粒的制备及其形成过程  

Preparation and Evolution Process of Dandelion-like Hierarchical Boehmite Particles

作　　者：韩强[1,2] 武晓峰[1] 廖玉超[1,2] 李丹[1,2] 岳仁亮[1] 刘海弟[1] 陈运法[1] 

机构地区：[1]中国科学院过程工程研究所,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《过程工程学报》2011年第3期503-508,共6页The Chinese Journal of Process Engineering

基　　金：国家自然科学基金资助项目(编号:51002154)

摘　　要：以硝酸铝为铝源、尿素为沉淀剂、一水合柠檬酸为结构调控剂,采用水热法合成了具有分级结构的蒲公英状γ-AlOOH颗粒,并经700℃煅烧4h得到具有相同分级结构的γ-Al2O3颗粒.结果表明,样品由500nm实心内核与松散的外层棒状结构组成,粒径约1μm,比表面积为238.77m2/g.对比实验发现,柠檬酸在水热体系中可诱导薄水铝石形成球状颗粒,并在其不足量的情况下诱导产生棒状颗粒.随反应进行,棒状颗粒在球状颗粒表面附着形成了具有分级结构的蒲公英状薄水铝石颗粒.Hierarchical boehmite particles with dandelion-like morphology was synthesized in the hydrothermal condition using aluminum nitrate as Al^3＋ source, urea as precipitator and citric acid as structure directing agent, which was further transformed to γ-Al2O3 product with the same morphology after simple heating post-treatment under 700℃ for 4 h. The crystal phase, morphology and microstructure of the samples were characterized. It is shown that the as-synthesized boehmite particles are 1 μm in diameter containing a solid interior with 500 nm in diameter and incompact outer shell formed by rod-shaped particles. The interesting dandelion-like structure evolution was further investigated by comparative experiments and a reasonable evolution mechanism was proposed, in which the boehmite samples tend to form spherical particles in the presence of citric acid, and rod-shaped particles can be produced when the citric acid is insufficient. The dandelion-like hierarchical boehmite particles are formed by rod-shaped particles adsorbed on the surface of the spherical particles.

关 键 词：水热法 薄水铝石 柠檬酸 蒲公英状 γ-氧化铝颗粒 

分 类 号：TF125[冶金工程—粉末冶金]