Alumina nanoparticles were synthesized following hydrothermal process at 170 degrees C for 6 h, using glucose and other water-based precursor materials. The uncalcined and calcined (550 degrees-1200 degrees C) particles were characterized by differential thermal analysis, thermogravimetry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and multipoint Brunauer-Emmett-Teller (BET) surface area. The microstructures of the calcined (at 550 degrees C) particles were examined by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). XRD and FTIR studies revealed that gamma-alumina (gamma-Al2O3) persisted up to 1000 degrees C followed by the appearance of alpha-alumina (alpha-Al2O3) at 1200 degrees C. BET surface area analysis confirmed that the specific surface area of gamma-Al2O3 was higher compared with alpha-Al2O3. Because of particle agglomeration, the crystallite sizes obtained by the BET method showed larger values than those determined by the XRD method for the samples calcined at 550 degrees-1200 degrees C. For 550 degrees C-treated sample, FESEM micrograph showed the aggregated particles of size 20-80 nm, while TEM image of the same sample revealed a particle size of 5-10 nm.
