Preparation method of gamma-AlOOH and gamma-Al2O3 nanotube and nanostructure

Abstract

Disclosed is a method for preparing gamma-AlOOH and gamma-Al2O3 through ionic-liquid-assisted hydrothermal synthesis. The method is characterized in that divalent metal ions are utilized to drive a decomposition reaction of a precursor so as to generate gamma-AlOOH in a mild condition. The method comprises main steps: 1) dissolving aluminium salt, an ionic liquid and divalent metal ions in deionized water according to different ratios, and performing uniform stirring; 2) transferring the obtained solution to a reactor and performing a reaction at different reaction temperatures for a while; 3) after the reaction is over, performing cooling to the room temperature, performing centrifugalization, performing alternate washing with deionized water and absolute ethanol, and performing drying to obtain a precursor of gamma-AlOOH; and 4) putting the precursor of gamma-AlOOH in a muffle furnace, and carrying out calcination to obtain a gamma-Al2O3 nanometer material with the identical shape. According to the method, gamma-AlOOH in the shape of a needle-shaped crystal whisker, a nanotube, and a bamboo-leaf-shaped nanometer flower and gamma-Al2O3 converted from gamma-AlOOH are synthesized. The obtained gamma-Al2O3 is relatively high in degree of crystallinity and specific surface area and has comparatively high potential of large-scale production.

Description

technical field [0001] The invention belongs to the field of inorganic nanometer materials. It specifically relates to a method for ionic liquid-assisted synthesis of high specific surface area gamma-alumina oxyhydroxide under mild conditions, and as a precursor, a method for obtaining gamma-alumina with the same shape through heat treatment. The invention is expected to be used in the fields of ceramics, catalysis, optics, adsorption, separation, photoelectric transfer devices, nanometer materials and composite materials. Background technique [0002] Among many non-metal and transition metal oxide materials, alumina is widely used in the fields of catalysis, ion exchange, adsorbent and ceramics because of its abundant resources, low price, large specific surface area, good chemical stability and non-toxicity. Wide range of applications. In particular, the low-temperature stable phase of alumina, γ-alumina, has abundant hydroxyl groups on its surface, and is the most wide...

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Problems solved by technology

However, these methods have the following problems: generally, it is necessary to add templates, surfactants or other auxiliary reagents, which makes the purification process of the product more complicated, and the removal process of the auxiliary reagents may also cause the destruction of the microstructure of the product, which is more complicated. The important thing is that the reorganization of the surface structure often leads to the reduction of the surface activity of γ-alumina nanomaterials; some methods require the addition of volatile or toxic organic solvents, high reaction temperature or two-step preparation to obtain the γ-alumina oxyhydroxide precursor Body and other issues

Although there are related patents for the preparation of γ-alumina nanotubes, such as: CN201110327588, CN200910035950 and CN200510086373, etc., the methods used are electrospinning, surfactants as templates, etc., and there are still commonalities in other solution chemistry literatures question

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