Synthesis of mesoporous γ-alumina nanorods using a double surfactant system by reverse microemulsion process

Mesoporous gamma-Al2O3 nanorods were synthesized by a reverse microemulsion (water in oil, w/o) technique using an aqueous-based alumina sol, the anionic surfactant AOT (sodium bis(2-ethylhexyl sulfosuccinate)), the non-ionic co-surfactant Span 80 (sorbitan monooleate) and cyclohexane as an organic solvent. The gamma-Al2O3 phase was obtained at 500 degrees C with a slight transformation to theta-Al2O3 at 700 degrees C-900 degrees C, while a mixed phase of gamma-, theta- and alpha-Al2O3 resulted at 1000 degrees C. The BET surface area, pore volume and average pore size of the 500 degrees C-treated sample was found to be 59.3 m(2) g(-1), 0.040 cm(3) g(-1) and 2.65 nm respectively, which changed slightly in the temperature range of 500 degrees C-900 degrees C. The mesoporous gamma-alumina nanorods were formed through rod-like micelle formation in the presence of surfactant/co-surfactant in organic solvent, which was illustrated by a proposed mechanism.