Teo Joong Jiat, Chang Yu, Zeng Hua Chun
Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260.
Langmuir. 2006 Aug 15;22(17):7369-77. doi: 10.1021/la060439q.
In this work, a template-free synthetic approach for generating single-crystalline hollow nanostructures has been described. Using the small optical band-gap cuprous oxide Cu(2)O as a model case, we demonstrate that, instead of normally known spherical aggregates, primary nanocrystalline particles can first self-aggregate into porous organized solids with a well-defined polyhedral shape according to the oriented attachment mechanism, during which chemical conversion can also be introduced. In contrast to the spherical aggregates, where the nanocrystallites are randomly joined together, the Cu(2)O nanocrystallites in the present case are well organized, maintaining a definite geometric shape and a global crystal symmetry. Due to the presence of intercrystallite space, hollowing and chemical conversion can also be carried out in order to create central space and change the chemical phase of nanostructured polyhedrons. It has been revealed that Ostwald ripening plays a key role in the solid evacuation process. Using this synthetic strategy, we have successfully prepared single-crystal-like Cu(2)O nanocubes and polycrystalline Cu nanocubes with hollow interiors. For the first time, we demonstrate that nanostructured polyhedrons of functional materials with desired interiors can be synthesized in solution via a combination of oriented attachment and Ostwald ripening processes.
在这项工作中，描述了一种用于生成单晶中空纳米结构的无模板合成方法。以小光学带隙的氧化亚铜Cu₂O作为模型案例，我们证明，与通常所知的球形聚集体不同，初级纳米晶体颗粒可以首先根据定向附着机制自聚集形成具有明确多面体形状的多孔有序固体，在此过程中也可以引入化学转化。与纳米微晶随机连接在一起的球形聚集体不同，在当前案例中的Cu₂O纳米微晶排列良好，保持明确的几何形状和整体晶体对称性。由于存在微晶间空间，还可以进行中空化和化学转化，以创建中心空间并改变纳米结构多面体的化学相。研究表明，奥斯特瓦尔德熟化在固体排空过程中起关键作用。使用这种合成策略，我们成功制备了具有中空内部的单晶状Cu₂O纳米立方体和多晶Cu纳米立方体。首次证明，可以通过定向附着和奥斯特瓦尔德熟化过程的组合在溶液中合成具有所需内部结构的功能材料的纳米结构多面体。
