Low Temperature Synthesis of Hexagonal Shaped α‐Al2O3 Using a Solvothermal Method

This study demonstrates the low temperature synthesis of α‐Al2O3 by solvothermal method using gibbsite alumina precursor in 1, 4‐butanediol solvent according to various pH conditions. In acidic solution, an orthorhombic boehmite (AlOOH) structure was obtained after solvothermal reaction. A significant result in this study was that the solvothermally synthesized alumina in pH = 9 at 300 °C for 36 h represented a rhombohedral α‐Al2O3 structure hexagonal shaped with about 1.5~2.0 μm of particle size. Otherwise, the α‐Al2O3 structure was rather changed to the mixture of a boehmite and α‐Al2O3 structures above pH = 11. In the case of α‐Al2O3 synthesized at pH = 9, the specific surface area was 26.18 m2/g, and the particles that were stable in acidic solution resulted in 61.80 mV of zeta potential.