Controlled synthesis of alumina in a spray flame aerosol reactor

In this study, a spray flame aerosol reactor (S-FLAR) is used to synthesize alumina nanoparticles. The as-produced powders are then characterized by X-ray diffraction, N₂ physisorption, and transmission electron microscopy to determine the crystal phase, surface area, particle size distribution, and morphology. The effects of the precursor, dispersion oxygen, and sheath oxygen rates on the characteristics of synthesized alumina were investigated. On increasing the precursor rate, decreasing the dispersion oxygen rate or sheath oxygen rate; the alumina powder surface area decreased. With increasing precursor rates and decreasing dispersion oxygen rates, the proportion of theta alumina increased and that of eta alumina decreased. When using an S-FLAR to synthesize alumina, the dispersion oxygen rate offers the best control of the surface area, while the precursor rate controls the crystal phase proportions. This result is useful for the design and operation of spray flame aerosol reactors to produce alumina-based catalysts.