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A composite formation route to well-crystalline manganese oxide nanocrystals: High catalytic activity of manganate-alumina nanocomposites

Title
A composite formation route to well-crystalline manganese oxide nanocrystals: High catalytic activity of manganate-alumina nanocomposites
Authors
Kim T.W.Yoo H.Kim I.Y.Ha H.-W.Han A.R.Chang J.-S.Lee J.S.Hwang S.-J.
Ewha Authors
황성주
SCOPUS Author ID
황성주scopus
Issue Date
2011
Journal Title
Advanced Functional Materials
ISSN
1616-301XJCR Link
Citation
vol. 21, no. 12, pp. 2301 - 2310
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
Manganese oxide nanocrystals are combined with aluminum oxide nanocrystals to improve their crystallinity via calcination without a significant increase of crystal size. A nanocomposite, consisting of two metal oxides, can be synthesized by the reaction between permanganate anions and aluminum oxyhydroxide keggin cations. The as-prepared manganese oxide-aluminum oxide nanocomposite is X-ray amorphous whereas heat-treatment gives rise to the crystallization of an α-MnO 2 phase at 600 °C and Mn 3O 4/Mn 2O 3 and γ-Al 2O 3 phases at 800 °C. Electron microscopy and N 2 adsorption-desorption-isotherm analysis clearly demonstrate that the as-prepared nanocomposite is composed of a porous assembly of monodisperse primary particles with a size of ∼20 nm and a surface area of >410 m 2 g -1. Of particular interest is that the small particle size of the as-prepared nanocomposite is well-maintained up to 600 °C, a result of the prevention of the growth of manganate grains through nanoscale mixing with alumina grains. The calcined nanocomposite shows very-high catalytic activity for the oxidation of cyclohexene with an extremely high conversion efficiency of >95% within 15 min. The present results show that the improvement of the crystallinity without significant crystal growth is very crucial for optimizing the catalytic activity of manganese oxide nanocrystals. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
DOI
10.1002/adfm.201100218
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자연과학대학 > 화학·나노과학전공 > Journal papers
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