Hollow ZnO microspheres with complex nanobuilding units

The synthesis of hollow zinc oxide (ZnO) microspheres through the assembly of numerous complex nanobuilding units, which were constructed from smaller unidirectionally attached nanorods, has been discussed. Specified amount of cetyl-trimethyl-ammonium-bromide (CTAB) was dissolved in pure ethanol under vigorous stirring. This solution was added to zinc nitrate solution, followed by addition of ethylenediamine. After stirring, the solution was transferred to a Teflon-lined stainless steel autoclave. ZnO products were obtained by centrifugation and through washing with water. Three tiers of organization of ZnO were observed including oriented attachment of the nanorods into central atoms, formation of complex multipod units, and construction of spheres with these nanobuilding units. This self-assembly process demonstrate new opportunities for template-assisted synthesis in the architecture of hollow structures and also in construction of structurally complex nanomaterials.