Template-free Synthesis and Formation Mechanism of Urchin-like Boehmite Superstructure

Novel urchin-like boehmite(AlOOH) superstructures consisting of nanorods were successfully synthe-sized by a template-free hydrothermal synthetic route in an ethanol-water solution.The crystal structures and the morphologies of boehmites were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),transmission electron microscope(TEM) and selected area electron diffraction(SAED).The effects of the precur-sors,the volume ratio of EtOH/H2O and reaction temperatures on the morphologies were also discussed.It is shown that the 3D urchin-like boehmite of uniform morphology and good dispersibility is prepared using AlCl3.6H2O as the precursor at 200℃ with the volume ratio(EtOH/H2O) of 1:2.The diameter of the urchin-like boehmite is 6-10μm,which is consisted of nanorods with the diameter of 60-80nm.The SAED pattern reveals the polycrystal-line nature of the urchin-like boehmite.The oriented attachment mechanism plays a key role on the formation of urchin-like boehmite superstructures.