Conductivity and stability of cobalt pyrovanadate

Cowin, Peter I. and Lan, Rong and Petit, Christophe T. G. and Zhang, Lei and Tao, Shanwen (2011) Conductivity and stability of cobalt pyrovanadate. Journal of Alloys and Compounds, 509 (10). pp. 4117-4121. ISSN 0925-8388

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Abstract

Cobalt pyrovanadate was successfully synthesised by a solid state route and the conductivity in both oxidising and reducing environments was determined for the first time. Impedance measurements between 300 degrees C and 700 degrees C in air determined that Co2V2O7 is an intrinsic semiconductor with activation energy of 1.16(3) eV. The conductivity in air reached a maximum of 4 x 10(-4) S cm(-1) at 700 degrees C. Semiconducting behaviour was also observed in 5% H-2/Ar, albeit with a much smaller activation energy of 0.04(4) eV. Between 300 degrees C and 700 degrees C the conductivity ranged from 2.45 S cm(-1) to 2.685 cm(-1), which is approaching the magnitude required for SOFC anode materials. Thermogravimetric analysis found a significant weight loss upon reduction of the compound. X-ray diffraction analysis, coupled with data from previous research, suggested compound degradation into Co2-xV1+xO4, CoO and VO. The redox instability and the low conductivity lead us to the conclusion that cobalt pyrovanadate is unsuitable for utilisation as an anode material for SOFCs although the conductivity is reasonable in a reducing atmosphere. (C) 2010 Elsevier B.V. All rights reserved.

Creators(s): Cowin, Peter I., Lan, Rong, Petit, Christophe T. G., Zhang, Lei and Tao, Shanwen;
Item type:Article
ID code:34069
Keywords:conductivity, cobalt pyrovanadate, anode, solid oxide fuel cell, oxide fuel cells, electrochemical properties, magnetic properties, oxidation, Chemistry, Materials Chemistry, Mechanics of Materials, Metals and Alloys, Mechanical Engineering
Subjects:Science > Chemistry
Department:Faculty of Engineering > Chemical and Process Engineering
Depositing user: Pure Administrator
Date deposited:16 Oct 2011 14:29
Last modified:07 Aug 2020 03:32
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URI:https://strathprints.strath.ac.uk/id/eprint/34069
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