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Title:
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Examining a potential fuel cell poison : a voltammetry study of the influence of carbon dioxide on the hydrogen oxidation capability of carbon supported Pt and PtRu anodes
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Author(s):
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Published by:
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Publication date:
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ECN
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1-10-2001
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ECN report number:
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Document type:
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ECN-RX--01-051
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Article (scientific)
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Number of pages:
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31
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Published in: Journal of the Electrochemical Society (ECS), , 2002, Vol.149, p.140-145.
Abstract:
Polymer electrolyte fuel cells being operated on reformed fossil fuels are exposed to large quantities of carbon dioxide. In order to elucidate the extent of the reverse water gas shift of CO2 on hydrogen covered fuel cells anodes to CO, an extensive cyclic voltammetry study has done on Pt and PtRu electrodes in sulfuric acid with varying hydrogen coverage. The electrodes used are representative of those being used in PEM fuel cells. The reverse shift reaction is facile on Pt/C, but with the surface not poisoned to the same extent as it does by exposure to CO saturated solutions. The reaction product is oxidized in a similar fashion to formic acid and methanol on platinum. The results indicate the formation of a stable adlayer, consisting of linear, bridge and multibonded CO in accordance to what has been proposed for unsupported platinum electrodes. PtRu/C fuel cell anodes are expected to be considerably more tolerant towards carbon dioxide that Pt/C anodes, with both the reaction suppresses and the adsorbate oxidation occuring at a lower potential.
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