Morphology evolution in hydrothermal synthesis of mesoporous alumina

Abstract

Boehmite with varied morphologies was successfully synthesized from aluminum ammonium sulfate hydrate and urea, as well as poly-glycol-2000 by hydrothermal method. The experimental results show that boehmite microspheres, microfibers and 3D hierarchical structured AlOOH can be fabricated only by adjusting hydrothermal temperature. SEM images indicate that boehmite decomposes into γ-Al2O3 phase after heat-treatment through a topotactical 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.