Mesostructured Forms of γ-Al₂O₃

Abstract

gamma-Al2O3 is one of the most extensively utilized metal oxides in heterogeneous catalysis. Conventional forms of this oxide typically exhibit a surface area and pore volume less than 250 m2/g and 0.5 cm3/g, respectively. Previous efforts to prepare mesostructured forms of alumina resulted only in structurally unstable derivatives with amorphous framework walls. The present work reports mesostructured aluminas with walls made of gamma-Al2O3, denoted MSU-gamma. These materials are structurally stable and provide surface areas and pore volumes up to 370 m2/g and 1.5 cm3/g, respectively. The key to obtaining these structures is the formation of a mesostructured surfactant/boehmite precursor, denoted MSU-S/B, assembled through the hydrolysis of an aluminum cation, oligomer, or molecule in the presence of a nonionic surfactant. Mesostructured, gamma-aluminas offer the possibility of improving the catalytic efficiency of many heterogeneous catalytic processes, such as petroleum refining, petrochemical processing, and automobile exhaust control.

Synthesis of Hierarchically Structured Aluminas under Controlled Hydrodynamic Conditions

“…34,37 Unlike in the templating mechanism, change in the chain length of the ionic amine surfactant used in the synthesis was reported to have no impact on the resulting mesopore structure. As demonstrated by samples 1, 9, and 10 that were synthesized with different carbon chain length ionic surfactants, this same invariance was observed in these materials.…”

PANI-derived polymer/Al2O3 nanocomposites: synthesis, characterization, and electrochemical studies

“…For example, alumina has a large surface area, adsorption capacity, and shows good wear resistance [20,21], so it is commonly used as catalyst, catalyst support, filter, and filler for polymers to improve mechanical properties [22,23]. At least, seven different transitional aluminas have been reported and Al 2 O 3 nanoparticle is perhaps, the most important one for its industrial applications [13,15,24,45].…”

Hydrothermal synthesis of alumina nanotubes templated by anionic surfactant

“…Most recently, considerable efforts have been directed towards the preparation of nano-structured alumina, due to their novel properties, such as high elastic modulus, thermal and chemical stability, and optical characteristics [14]. Up to date, nanosized Al 2 O 3 with different morphologies, such as nanotubes [8,17 -21], nanowires [22], nanobelts [22], nanofibers [23,24], rod-shaped nanoparticles [25] and whiskers [26], has been synthesized by a variety of routes. However, there has been no report on the formation of nanotubular alumina in the presence of the anionic surfactant, sodium dodecyl sulfonate (SDS), as structure-directing agent.…”