Activating the Growth of High Surface Area Alumina Using a Liquid Galinstan Alloy

Abstract

The growth of high surface area alumina has been investigated with the use of a liquid Galinstan alloy [66.5% (wt %) Ga, 20.5% In and 13.0% Sn] as an activator for aluminum. In this process, the aluminum is slowly dissolved into the gallium–indium–tin alloy, which is then selectively oxidized at ambient temperature and pressure under a humid stream of flowing CO 2 or N 2 to yield amorphous alumina. This preparative route represents a simple and low toxicity approach to obtain amorphous high surface area alumina with very low water content. The as-synthesized high surface area alumina aerogel was a blue-colored solid owing to the Rayleigh scattering by its dendritic fibrous nanostructure consisting of mainly alumina with small amounts of water. Upon annealing at 850 °C, the amorphous product transformed into γ-Al 2 O 3 , as well as θ-Al 2 O 3 upon annealing at 1050 °C. Elemental analysis by energy-dispersive spectroscopy provides further evidence that the high surface area alumina is composed of only aluminum and oxygen. The surface area of the amorphous alumina varied from ∼79 to ∼140 m 2 /g, depending on the initial weight percentage of aluminum used in the alloy. A correlation between the initial concentration of aluminum in the alloy and the surface area of the alumina product was found to peak at ∼30% Al. These results suggest a novel route to the formation of amorphous alumina aerogel-type materials.

Pushing the Limits of Energy Performance in Micron-Sized Thermite: Core–Shell Assembled Liquid Metal-Modified Al@Fe2O3 Thermites

“…The high-resolution XPS spectra of Al 2p, Ga 2p, In 3d, and Sn 3d are displayed in Figure S8, which demonstrated that the surface of aluminum was coated by Galinstan and its oxides, forming a composite oxide layer. The interaction of Galinstan and Al produced an amalgam, which could inhibit the production of the passivation layer . More importantly, the above signals completely disappeared in GLM-Al@Fe 2 O 3 , indicating that the GLM-Al surface is completely enwrapped by Fe 2 O 3 , forming a core–shell structure.…”

“…When Galinstan is in contact with aluminum, it could wet the surface of aluminum and penetrate into the grain boundaries through a process known as liquid metal embrittlement, which leads to the activation of the Al surface and changes the internal stress . The amalgam produced by the interaction of the Galinstan and Al could inhibit the formation of the passivation layer on the Al surface, and the damaged passive alumina and increased internal stress may expedite the release of aluminum during the reaction, resulting in the increase of its reactivity. ,− Moreover, benefiting from liquid metal embrittlement, the particle size of the larger micron-sized aluminum will be reduced during sonication and stirring. Thus, this method provides a foundation for the preparation of different kinds of thermites based on liquid metal-modified Al (GLM-Al).…”

Cobalt-Doped Aluminum Aerogels as Photocatalyst Fabricated by a Liquid Metal Reaction Method in the Laboratory

“…Due to these characteristics, aerogels are regarded as outstanding and promising carriers of catalysts for photocatalysis. Unfortunately, conventional fabrication methods of aerogels in industry, such as the sol–gel method, are usually time-consuming and expensive, which is obviously not appropriate as methods in an experimental course at the university level and poses challenges to meet the teaching requirements in universities. − So, we introduce the liquid metal reaction method that is simple, innocuous, and sustainable to fabricate aluminum-based aerogels in common laboratories. − In this experiment, students are introduced to the synthesis of cobalt-doped aluminum hydroxide aerogels with different doping ratios by the liquid metal method and use advanced equipment to characterize the properties of these samples. They also evaluate the photocatalytic performances of cobalt-doped (Co-doped) aluminum hydroxide aerogels under different conditions and discuss the photocatalytic mechanism in the end.…”

Superhydrophobic and luminescent highly porous nanostructured alumina monoliths modified with tris(8-hydroxyquinolinato)aluminium

“…Among other methods of aerogel-like materials production, controlled oxidation of metallic aluminium through the Al-Hg layer in humid air is truly a low-cost and facile method, leading to the formation of highly porous 3D monoliths consisting of nanofibrils of aluminium oxyhydroxides (NOA, Al 2 O 3 •nH 2 O) [3,4]. Additional functionalization of NOA, which is typically achieved by the binding of various species on their surface, e.g., by the impregnation of NOA in a modifier solution, significantly extends their application [5][6][7][8]. By the impregnation techniques, metal and metal oxide nanoparticles [3,5,[9][10][11], as well as carbon nanotubes [12], were immobilized in the matrix of pre-annealed NOA materials.…”