Morphological and structural evolution of alpha-MnO{sub 2} nanorods synthesized via an aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction

Journal Article · Thu Apr 15 04:00:00 EDT 2010 · Journal of Solid State Chemistry

OSTI ID:21372567

Xiaobo, Fu ^[1]; Huan, Wang; Ng, Ka Ming ^[1]

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1. Nano and Advanced Materials Institute Limited, Clear Water Bay, Kowloon (Hong Kong)

An aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction under mild conditions was used to synthesize alpha-MnO{sub 2} nanorods. The morphological and structural evolution of alpha-MnO{sub 2} 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-MnO{sub 2} nanorods was found to proceed through three steps: (1) Amorphous or poorly ordered nuclei formed first. (2) Then hollow nanoshperes consisting of gamma-MnO{sub 2} nanorods formed via the Ostwald ripening process. (3) The hollow nanospheres broke down and the gamma-MnO{sub 2} nanorods finally transformed into the alpha-MnO{sub 2} nanorods with increasing temperature or reaction time. The phase transformation from gamma-MnO{sub 2} to alpha-MnO{sub 2} nanorods was accomplished by a short-range rearrangement of MnO{sub 6} octahedra. In addition, the performance of the MnO{sub 2} 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. - Graphical abstract: alpha-MnO{sub 2} nanorods were synthesized via an aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction under mild conditions.

• OSTI ID: 21372567
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 4 Vol. 183; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
CATALYSTS
CHALCOGENIDES
CHARGED PARTICLES
COHERENT SCATTERING
CRYSTALLIZATION
DIFFRACTION
ELECTRON MICROSCOPY
IONS
MANGANESE COMPOUNDS
MANGANESE IONS
MANGANESE OXIDES
MICROSCOPY
NANOSTRUCTURES
OXIDES
OXYGEN COMPOUNDS
PERMANGANATES
PHASE TRANSFORMATIONS
SCANNING ELECTRON MICROSCOPY
SCATTERING
TRANSITION ELEMENT COMPOUNDS
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION