Electrochemical Formation Mechanism for the Controlled Synthesis of Heterogeneous MnO2/Poly(3,4-ethylenedioxythiophene) Nanowires

The formation mechanism of a coaxial manganese oxide/poly(3,4-ethylenedioxythiophene) (MnO2/PEDOT) nanowire is elucidated herein by performing electrodeposition of MnO2 and PEDOT on Au-sputtered nanoelectrodes with different shapes (ring and flat-top, respectively) within the 200 nm diameter pores o...

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Bibliographic Details
Published in:ACS nano 2011-07, Vol.5 (7), p.5608-5619
Main Authors: Liu, Ran, Duay, Jonathon, Lee, Sang Bok
Format: Article
Language:English
Subjects:
Aluminum oxide
Aluminum Oxide - chemistry
Bridged Bicyclo Compounds, Heterocyclic - chemistry
Deposition
Electric Capacitance
Electrochemistry
Electrodes
Electroplating - methods
Formations
Manganese Compounds - chemistry
Nanostructure
Nanotechnology - methods
Nanowires
Nanowires - chemistry
Oxides - chemistry
Polymers - chemistry
Porosity
Synthesis
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Summary:The formation mechanism of a coaxial manganese oxide/poly(3,4-ethylenedioxythiophene) (MnO2/PEDOT) nanowire is elucidated herein by performing electrodeposition of MnO2 and PEDOT on Au-sputtered nanoelectrodes with different shapes (ring and flat-top, respectively) within the 200 nm diameter pores of an anodized aluminum oxide (AAO) template. It is found that PEDOT prefers to grow on the sharp edge of the ring-shaped electrode, while MnO2 is more likely to deposit on the flat-top electrode due to its smooth surface. The formation of coaxial nanowires is shown to be a result of simultaneous growth of core MnO2 and shell PEDOT by an analysis of the current density resulting from electrochemical deposition. Furthermore, the structures of the MnO2/PEDOT coaxial nanowires were studied for their application as supercapacitors by modifying their coelectrodeposition potential. A potential of 0.70 V is found to be the most favorable condition for synthesis of MnO2/PEDOT coaxial nanowires, resulting in a high specific capacitance of 270 F/g. Additionally, other heterogeneous MnO2/PEDOT nanostructures are produced, such as nanowires consisting of MnO2 nanodomes with PEDOT crowns as well as segmented MnO2/PEDOT nanowires. This is accomplished by simply adjusting the parameters of the electrochemical deposition. Finally, in smaller diameter (50 nm) AAO channels, MnO2 and PEDOT are found to be partially assembled into coaxial nanowires due to the alternative depletion of Mn(II) ions and EDOT monomers in the smaller diameter pores.
ISSN:1936-0851
1936-086X
DOI:10.1021/nn201106j