What is it about?
Aluminum hydrous oxides and their derivatives were prepared by a facile solvothermal process in the presence of formamide, di-methyl formamide and di-ethyl formamide as solvents at 150°C/24 h. The as-synthesized products were calcined at 500°C/1 h to obtain -Al2O3. The crystallization behavior and microstructure of the pre- and post-calcination products were studied by X-ray diffraction, and transmission electron microscopy, respectively. The surface textural properties of the calcined samples were investigated by N2 adsorption-desorption analysis. The formamide and its derivatives played a significant role in tuning textural properties of the calcined products. The di-ethyl formamide based sample exhibited enhanced BET surface area and pore volume of 517 m2g-1 and 2 cm3g-1, respectively. Both the as-prepared and calcined samples showed variable morphologies and crystallinity by using different solvents. The trend in morphological changes as nanosheet → nanorod → nanowire bundles occurred in the presence of formamide, di-methylformamide, and di-ethylformamide, respectively. A tentative mechanism has been illustrated for the formation of the products.
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Why is it important?
Herein, we have invesigated the role of formamide and its derivatives (dimethyl formamide and diethyl formamide) as solvents (termed as formamide and formamide derivative solvents, FDS) in determining morphological evolution of aluminum hydrous oxides, and textural features of their calcined products. In this study, the effect of reaction time, amount of FDS as well as their chemical behaviors has also been investigated in terms of structural features and physicochemical properties of aluminum hydrous oxides and their calcined products. To the best of our knowledge, the use of formamide and its derivatives have been employed first time for the synthesis of morphologically controlled alumina based products with significant increase in surface area and high pore volume of the calcined products. This study provides new insights into the design and synthesis of tunable porous alumina of various shapes, which are of significant interest for applications in catalysis, adsorption, separation etc.
Perspectives
In this study, the solvent effect of formamide, di-methyl formamide and di-ethyl formamide has been illustrated on the formation of aluminum hydrous oxides and their calcined products in terms of controllable morphology and tunable textural properties. For better understanding of the physico-chemical properties of the pre- and post calcined products, reaction time and concentration of the solvents were varied. Ammonia, dimethyl amine and diethyl amine obtained via the hydrolysis of formamide, dimethyl formamide and diethyl formamide, respectively play a significant templating and structure directing role in tailoring textural properties of the calcined products obtained under different conditions. The trend in morphological changes in the presence of formamide, di-methylformamide, and di-ethylformamide is governed by sticking and scrolling mechanistic pathway followed by conventional dissolution-recrystalization mechanism. This study seems to be applicable for the synthesis of other related materials with controllable morphology and tunable textural properties for various applications such as catalysis, adsorption, and separation etc.
Milan Naskar
Read the Original
This page is a summary of: Morphologically Tuned Aluminum Hydrous Oxides and Their Calcined Products, Journal of the American Ceramic Society, April 2016, Wiley,
DOI: 10.1111/jace.14258.
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