One-step synthesis of flower-like η-Al 2 O 3 via supercritical hydrothermal method

Micro & nano letters

article

Behrouz Jalouli¹  Aref Abbasi²  Seyed Mohammad Musavi Khoei¹ 

[1] Department of Mining and Metallurgy, Amirkabir University of Technology;School of Metallurgy and Materials Engineering, Iran University of Science and Technology (IUST)

关键词: desorption;    crystal growth from solution;    scanning electron microscopy;    calcination;    nanofabrication;    transmission electron microscopy;    alumina;    X-ray diffraction;    powders;    adsorption;    nitrogen;    high-temperature effects;    surface morphology;    nanostructured materials;    supercritical hydrothermal method;    surfactant;    molten salt bath;    reactor temperature;    scanning electron microscopy;    N2 adsorption-desorption analysis;    supercritical fluid;    flower-like η-Al2O3 nanostructure;    calcination;    high temperature;    X-ray powder diffraction;    specific surface area;    Ostwald ripening;    morphology;    N2;    Al2O3;   

DOI  :  10.1049/mnl.2020.0244

学科分类：计算机科学（综合）

来源: Wiley

【 摘 要 】

In this Letter, flower-like η-Al 2 O 3 nanostructure was synthesised via hydrothermal method without any surfactant or further calcination. A molten salt bath rose the reactor temperature as much as 500°C to achieve the supercritical condition. Such a high temperature caused a rapid one-step synthesis in two minutes. Al(NO 3 ) 3 and NaOH were the only precursors. Synthesised powders were investigated by X-ray powder diffraction and scanning electron microscope, and the specific surface area was also determined by N 2 adsorption–desorption analysis. Increasing reaction time >2 min caused undesired Ostwald ripening. So instead of giving more time, a small amount of NaOH was added to form the η-Al 2 O 3 phase. Moreover, the morphology of η-Al 2 O 3 changed to flower-like by increasing the density of the supercritical fluid. Finally, the probable mechanism of flower-like morphology formation was proposed in two steps.

【 授权许可】

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