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Tuning the Surface Morphology and Pseudocapacitance of MnO 2 by a Facile Green Method Employing Organic Reducing Sugars
Published in American Chemical Society
Volume: 1
Issue: 8
Pages: 3654 - 3664
In the present work, three different MnO 2 nanostructures, nanoneedles, hollow tubes, and nanorods of MnO 2 , have been synthesized by a simple redox reaction between permanganate and organic sugars at room temperature. The MnO 2 samples were characterized by a variety of analytical techniques. The results illustrate that the organic reducing sugars of mannose, galactose, and glucose effectively tune the morphology, crystallinity, and pore structure of the MnO 2 material. The nanoneedles and hollow tubes were found to be β-MnO 2 , while the nanorods were α-MnO 2 . The formation of different MnO 2 nanostructures appears to be a kinetically driven process that proceeds in a quite distinctive way in the presence of different organic reducing sugars. Cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) tests were conducted to evaluate the charge storage behavior of the α- and β-MnO 2 nanostructures. Among all three MnO 2 samples, β-MnO 2 composed of nanoneedles delivered a large specific capacitance, C S (∼365 F g -1 at 0.5 A g -1 ) with improved rate capability (56% retention at 12 A g -1 ) and excellent cyclability (82% retention at 2000 cycles). The elegant combination of the high specific surface area (∼146 m 2 g -1 ) and 1D-nanoneedle structure of β-MnO 2 , enhances the electrode-electrolyte contact area and hence provides a number of active sites for fast charge-discharge propagations. © Copyright 2018 American Chemical Society.
About the journal
JournalData powered by TypesetACS Applied Energy Materials
PublisherData powered by TypesetAmerican Chemical Society
Open AccessNo