Fabrication of high-surface-area γ-alumina by thermal decomposition of AACH precursor using low-temperature solid-state reaction

In this paper, systematical investigation has been made for the new simple synthesis pathway of catalytic alumina with high surface area through thermal decomposition of ammonium aluminum carbonate hydroxide (AACH), which has been prepared by a low-temperature solid-state reaction in non-aqueous system. The results indicate that the molar ratios of NH4HCO3/Al influence crystallinities and the morphologies of AACH. Well-crystallized AACH with nanorod morphology and low-crystallized AACH with cluster structure can be obtained with different molar ratios NH4HCO3/Al. The γ-Al2O3 product with high surface area (511 m2/g) can be obtained from the calcination of AACH at 500 °C. Moreover, the results also indicate that crystallinities and morphologies of AACH affect their thermal decomposition behaviors. In addition, the formation of high-surface-area is possibly attributed to intracrystalline porosity of as-prepared γ-Al2O3.