Morphological and structural evolution of α-MnO2 nanorods synthesized via an aqueous route through MnO4-/Mn2+ reaction

被引:24
作者
Fu, Xiaobo [1 ,2 ]
Feng, Jiyun [1 ]
Wang, Huan [1 ,2 ]
Ng, Ka Ming [1 ,2 ]
机构
[1] Nano & Adv Mat Inst Ltd, Kowloon, Hong Kong, Peoples R China
[2] Hong Kong Univ Sci & Technol, Dept Chem & Biomol Engn, Kowloon, Hong Kong, Peoples R China
关键词
Manganese dioxide; Nanorods; Crystallization-dissolution; Catalytic oxidation; MANGANESE OXIDE; GROWTH; NANOWIRES; BETA-MNO2; ALCOHOLS; DIOXIDE;
D O I
10.1016/j.jssc.2010.02.002
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
An aqueous route through MnO4-/Mn2+ reaction under mild conditions was used to synthesize alpha-MnO2 nanorods. The morphological and structural evolution of alpha-MnO2 nanorods during their growth were tracked by Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET analysis. The crystallization of alpha-MnO2 nanorods was found to proceed through three steps: (1) Amorphous or poorly ordered nuclei formed first. (2) Then hollow nanoshperes consisting of gamma-MnO2 nanorods formed via the Ostwald ripening process. (3) The hollow nanospheres broke down and the gamma-MnO2 nanorods finally transformed into the alpha-MnO2 nanorods with increasing temperature or reaction time. The phase transformation from gamma-MnO2 to alpha-MnO2 nanorods was accomplished by a short-range rearrangement of MnO6 octahedra. In addition, the performance of the MnO2 materials as a catalyst was evaluated in the aerobic oxidation of benzyl alcohol, showing that their catalytic activities were mainly dependent on their BET surface areas. (C) 2010 Elsevier Inc. All rights reserved.
引用
收藏
页码:883 / 889
页数:7
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