Journal Article

PUBDB-2017-09669

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Structural properties and thermal stability of cobalt- and chromium-doped $\mathrm{\alpha-MnO_{2}}$ nanorods

Cerc Korošec, R. (Corresponding author) ; Umek, P. ; Gloter, A. ; Padežnik Gomilšek, J.Extern* ; Bukovec, P.

2017
Beilstein-Institut zur Förderung der Chemischen Wissenschaften Frankfurt, M.

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Please use a persistent id in citations: doi:10.3762/bjnano.8.104  doi:10.3204/PUBDB-2017-09669

Abstract: $\alpha$-MnO$_{2}$ nanorods were synthesized via the hydrothermal decomposition of KMnO$_4$ in an acidic environment in the presence of Co$^{2+}$ and Cr$^{3+}$ ions. Reactions were carried out at three different temperatures: 90, 130 and 170 °C. All prepared samples exhibit a tetragonal MnO$_2$ crystalline phase. SEM–EDS analysis shows that cobalt cations are incorporated to a higher degree into the MnO$_2$ framework than chromium ions, and that the content of the dopant ions decreases with increasing reaction temperature. The oxidation of Co$^{2+}$ to Co$^{3+}$ during the reaction was proved by an XANES study, while EXAFS results confirm that both dopant ions substitute Mn$^{4+}$ in the center of an octahedron. The K/Mn ratio in the doped samples synthesized at 170 °C is significantly lower than in the undoped samples. Analysis of an individual cobalt-doped $\alpha$-MnO$_{2}$ nanorod with HAADF-STEM reveals that the distribution of cobalt through the cross-section of the nanorod is uniform. The course of thermal decomposition of the doped nanorods is similar to that of the undoped ones. Dopant ions do not preserve the MnO$_2$ phase at higher temperatures nor do they destabilize the cryptomelane structure.

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Contributing Institute(s):

1. DOOR-User (DOOR)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)
2. FS-Proposal: II-20080058 EC (II-20080058-EC) (II-20080058-EC)
3. FS-Proposal: I-20110082 EC (I-20110082-EC) (I-20110082-EC)

Experiment(s):

1. DORIS Beamline C (DORIS III)

Appears in the scientific report 2017

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Database coverage:
; ; ; ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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