Facile fabrication of urchin-like hollow boehmite and alumina microspheres with a hierarchical structure via Triton X-100 assisted hydrothermal synthesis

Hierarchically organized urchin-like hollow boehmite and alumina microspheres were successfully synthesized via a facile tert-octyl-phenyl polyoxyethylene ether (Triton X-100) assisted hydrothermal route using aluminum sulfate and urea as an aluminum source and a precipitant, respectively. The samples were characterized by X-ray diffraction (XRD), thermogravimetry (TG), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N₂ adsorption-desorption technique. SEM and TEM verified the hierarchically organized urchin-like hollow structure of the as-prepared samples with needles of about 1 μm length. The morphology and textual structure of boehmite and alumina can be handily controlled by adjusting the concentration of Triton X-100. Urchin-like alumina with a large S_BET value of 146.91 m² g^-1, a pore volume of 0.92 cm³ g^-1 and a hierarchical structure was obtained at C_TX = 0.01 M. Furthermore, a possible mechanism was also proposed for the formation of this hierarchically organized urchin-like boehmite.