具有三维贯通多级孔道结构大孔氧化铝的制备与表征

采用铝溶胶晶种引入、结合相分离的方法制备了具有三维贯通多级孔道结构的大孔氧化铝材料。采用扫描电镜（SEM）、X射线衍射（XRD）、N₂吸附-脱附、压汞、核磁共振波谱（NMR）等测试方法对所得材料进行了表征。结果表明，该氧化铝材料具有200-600 nm的均匀分布且贯通的连续大孔孔道，经550℃焙烧即可得到结晶态γ-氧化铝。大孔氧化铝比表面积达到366 m²/g，具有以5 nm及400 nm为中心的较为集中的介孔-大孔多级孔道分布。焙烧后的样品中，铝具有四、六两种配位状态。制备过程中，聚环氧乙烷（PEO）作为诱导剂引发固-液两相分离，形成具有三维贯通多级孔道结构大孔氧化铝，而凝胶中引入铝溶胶时，AlOOH晶粒与铝交联水合物均相伴生，在凝胶过程诱导铝交联水合物转变为AlOOH，最终使大孔氧化铝在较低的焙烧温度即可转化为γ-氧化铝。

Synthesis and characterization of hierarchically porous alumina with three-dimensional interconnected pore structure

Hierarchically porous alumina with three-dimensional interconnected pore structure was prepared by phase separation method with alumina sol as the seed crystals; the alumina material was then characterized by SEM, XRD, N₂ sorption, mercury porosimetry and NMR. The results reveal that the ierarchically porous alumina is provided with macropores of 200-600 nm in gamma phase; it has a high surface area of 366 m²/g and narrow double pore size distributions at about 5 and 400 nm. As revealed by NMR, AlO₄, and AlO₆ are formed in the calcined alumina sample. It is then suggested that during the synthesis, PEO acted as a seed can inspire phase separation, generating the interconnected three-dimensional macropores, while the crystalline grain in the sol may induce the aluminum hydrates to form active AlOOH, which is then transformed to gamma crystalline phase by calcination even at mild temperature.