A Novel Synthesis Route of Mesoporous γ-Alumina from Polyoxohydroxide Aluminum

This precursor was obtained from aluminum oxidation in alkaline water-ethanol solvent in the presence of d-glucose that induces the formation of a gel, which leads to the POAH powder after ethanolic treatment. Precipitated POHAs were calcined at different temperatures (300, 400, 700 and 900 °C) resulting in the metastable γ-Al2O3 phase.

Whereas at 300 °C no γ-Al2O3 phase was formed, unexpectedly, mesoporous γ-Al2O3 was obtained at 400 ºC having a high specific surface area (282 m2/g) and a narrow pore size distribution. At higher temperatures, the aluminas had the expected decrease in surface area: 166 m2/g (700 °C) and 129 m2/g (900 °C), respectively. The structural change from POHA to alumina calcined at 400 ºC occurs directly without the need to isolate the hydroxide or oxyhydroxide aluminum precursors.