Structural Distortion in MnO(2) Nanosheets and Its Suppression by Cobalt Substitution

Co–Mn oxide nanosheets with the chemical composition H(0.23)Co(0.23)Mn(0.77)O(2) (C23M77NS) and MnO(2) nanosheets (M100NS) were prepared by exfoliation of layer-structured oxides via chemical processing in an aqueous medium. The optical properties of C23M77NS and M100NS were compared using UV-Vis sp...

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Detalles Bibliográficos
Autores principales: Suzuki, Shinya, Miyayama, Masaru
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5666460/
https://www.ncbi.nlm.nih.gov/pubmed/28946678
http://dx.doi.org/10.3390/nano7100295
Descripción
Sumario:Co–Mn oxide nanosheets with the chemical composition H(0.23)Co(0.23)Mn(0.77)O(2) (C23M77NS) and MnO(2) nanosheets (M100NS) were prepared by exfoliation of layer-structured oxides via chemical processing in an aqueous medium. The optical properties of C23M77NS and M100NS were compared using UV-Vis spectroscopy, and the valence states of Mn and Co and local structures around them were examined using X-ray absorption spectroscopy. M100NS with an average Mn valence of 3.6 exhibits large structural distortion, whereas C23M77NS with an average Mn valence of 4.0 does not exhibit structural distortion. Spontaneous oxidization of Mn occurs during ion-exchange and/or exfoliation into nanosheets. These results have originated the hypothesis that structural distortion determines the valence state of Mn in compounds with CdI(2)-type-structured MnO(2) layers.

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