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dc.contributor.author최진호-
dc.contributor.author황성주-
dc.date.accessioned2016-08-28T12:08:37Z-
dc.date.available2016-08-28T12:08:37Z-
dc.date.issued2009-
dc.identifier.issn1932-7447-
dc.identifier.otherOAK-6128-
dc.identifier.urihttps://dspace.ewha.ac.kr/handle/2015.oak/220409-
dc.description.abstract1D nanorods/nanowires of manganese oxides with different crystal structures and morphologies were prepared and characterized to understand the influence of the Mn valence in the solid-state precursor on the electrochemical activity of these nanomaterials and to elucidate the mechanism responsible for the excellent activity of β-MnO2 nanorods as well. According to powder X-ray diffraction analyses, treating manganese oxide precursors that have an oxidation state of ≤+3 with persulfate ions under hydrothermal conditions yields manganese oxides with the β-MnO2 structure. In contrast, the use of a LiMn2O4 precursor with a higher Mn valence leads to the formation of the α-MnO2-structured manganese oxide. Electron microscopic studies clearly show a 1D nanorod-type morphology for the β-MnO2 material, whereas a 1D nanowire-type morphology with a higher aspect ratio is observed for the α-MnO2 material. The diameter of the β-MnO2 nanorods decreases as the Mn valence in the precursors becomes smaller. According to electrochemical measurements, the formation of nanorods dramatically improves the electrode performance of the β-MnO2 phase. This compares with a relatively weak performance enhancement for the α- and δ-MnO2 phases upon the nanowire formation. The optimum electrode property results from the smaller β-MnO2 nanorods prepared with the MnO precursor. 7Li magic angle spinning nuclear magnetic resonance spectroscopy clearly demonstrates that Li+ ions in the lithiated β-MnO2 phase are adsorbed mainly on the sample surface. On the basis of this finding, we attribute the improved electrode performance of the β-MnO2 nanorods to their expanded surface area. © 2009 American Chemical Society.-
dc.languageEnglish-
dc.titleOrigin of improved electrochemical activity of β-MnO2 nanorods: Effect of the Mn valence in the precursor on the crystal structure and electrode activity of manganates-
dc.typeArticle-
dc.relation.issue51-
dc.relation.volume113-
dc.relation.indexSCIE-
dc.relation.indexSCOPUS-
dc.relation.startpage21274-
dc.relation.lastpage21282-
dc.relation.journaltitleJournal of Physical Chemistry C-
dc.identifier.doi10.1021/jp908556h-
dc.identifier.wosidWOS:000272712700003-
dc.identifier.scopusid2-s2.0-73849091700-
dc.author.googleKim I.Y.-
dc.author.googleHa H.-W.-
dc.author.googleKim T.W.-
dc.author.googlePaik Y.-
dc.author.googleChoy J.-H.-
dc.author.googleHwang S.-J.-
dc.contributor.scopusid최진호(8044393000)-
dc.contributor.scopusid황성주(7404626171)-
dc.date.modifydate20190901081003-
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자연과학대학 > 화학·나노과학전공 > Journal papers
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