Surface texture of microcrystalline tunnel-structured manganese(IV) oxides: Nitrogen sorptiometry and electron microscopy studies

被引:2
作者
Ali, AA [1 ]
Al-Sagheer, FA [1 ]
Zaki, MI [1 ]
机构
[1] Kuwait Univ, Fac Sci, Dept Chem, Safat 13060, Kuwait
关键词
D O I
10.1260/02636170260504314
中图分类号
O69 [应用化学];
学科分类号
081704 ;
摘要
Three different modifications of manganese(IV) oxide, viz. cryptomelane, nsutite and todorokite-like, were synthesized by hydrothermal methods. The bulk chemical composition, phase composition, crystalline structure and particle morphology of the resulting materials were determined by thermogravimetry, atomic absorption spectroscopy, X-ray diffractometry, infrared spectroscopy and scanning electron microscopy. The surface chemical composition, texture and structure were assessed using X-ray photoelectron microscopy, nitrogen sorptiometry and high-resolution electron microscopy. The results highlighted the hydrothermal conditions under which such tunnel-structured modifications of manganese(IV) oxide can be successfully synthesized. Moreover, they revealed that (i) the bulk was microcrystalline, (ii) the crystallites were either fibrils (cryptomelane and nsutite) or rod-like (todorokite) with low-index exposed facets, (iii) the surface chemical composition mostly reflected that of the bulk and (iv) the surface texture was linked with high specific areas, slit-shaped mesopores associated with particle interstices and micropores which allowed surface accessibility to the bulk tunnels of the test oxides. The application of such test oxides as shape-selective oxidation catalysts appears worthy of investigation.
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收藏
页码:619 / 632
页数:14
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