Abstract |
Manganese oxides (MnOx ) are considered to be promising catalysts for water oxidation. Electrodeposited MnOx films from aqueous electrolytes have previously been shown to exhibit a lower catalytic action than films deposited from ionic liquids when tested in strongly alkaline conditions. In this study, we describe a thermal treatment that converts the MnOx films deposited from aqueous electrolytes to highly catalytic films with comparable activity to ionic-liquid-deposited films. The films deposited from aqueous electrolytes show a remarkable improvement in the catalysis of water oxidation after heat treatment at a low temperature (≤120 °C) for 30 min. The films were characterised by using XRD and SEM, and energy-dispersive X-ray (EDX), FTIR and Raman spectroscopy, which indicate that dehydration occurs during the heat treatment without significant change to the microstructure or bulk composition. The X-ray absorption spectroscopy (XAS) results show the growth of small amounts (ca. 3-10 %) of reduced Mn species (Mn(II) or Mn(III) ) after heat treatment. The dehydration process removes structural water and hydroxyl species to result in a conductivity improvement and a more active catalyst, thereby contributing to the enhancement in water oxidation performance.
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Authors | Fengling Zhou, Alex Izgorodin, Rosalie K Hocking, Vanessa Armel, Leone Spiccia, Douglas R Macfarlane |
Journal | ChemSusChem
(ChemSusChem)
Vol. 6
Issue 4
Pg. 643-51
(Apr 2013)
ISSN: 1864-564X [Electronic] Germany |
PMID | 23460606
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Chemical References |
- Manganese Compounds
- Oxides
- Water
- manganese oxide
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Topics |
- Catalysis
- Hot Temperature
- Manganese Compounds
(chemistry)
- Microscopy, Electron, Scanning
- Oxidation-Reduction
- Oxides
(chemistry)
- Spectroscopy, Fourier Transform Infrared
- Spectrum Analysis, Raman
- Water
(chemistry)
- X-Ray Absorption Spectroscopy
- X-Ray Diffraction
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