Morphology Evolution in Hydrothermal Synthesis of Mesoporous Alumina

Boehmite with varied morphologies was successfully synthesized from aluminum ammonium sulfate hy- drate and urea, as well as poly-glycol-2000 by hydrothermal method. The experimental results show that boehmite mi- crospheres, microfibers and 3D hierarchical structured AlOOH can be fabricated only by adjusting hydrothermal tem- perature. SEM images indicate that boehmite decomposes into γ-Al2O3 phase after heat-treatment through a topotacti- cal process. TEM studies present that the mesopores are formed in γ-Al2O3 particles. Based on these investigations, a temperature-dependent morphology formation mechanism is proposed. Besides, the as-synthesized alumina excited at 325 nm shows emission in the range of 380 nm to 500 nm, centered at 409 nm and 467 nm.