Electrocatalytic hydrogen oxidation by an enzyme at high carbon monoxide or oxygen levels
- Kylie A. Vincent*,
- James A. Cracknell*,
- Oliver Lenz†,
- Ingo Zebger‡,
- Bärbel Friedrich†, and
- Fraser A. Armstrong*,§
- *Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; †Institut für Biologie/Mikrobiologie, Humboldt-Universität zu Berlin, Chausseestrasse 117, 10115 Berlin, Germany; and ‡Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
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Edited by Helmut Beinert, University of Wisconsin, Madison, WI (received for review May 31, 2005)
Abstract
Use of hydrogen in fuel cells requires catalysts that are tolerant to oxygen and are able to function in the presence of poisons such as carbon monoxide. Hydrogen-cycling catalysts are widespread in the bacterial world in the form of hydrogenases, enzymes with unusual active sites composed of iron, or nickel and iron, that are buried within the protein. We have established that the membrane-bound hydrogenase from the β-proteobacterium Ralstonia eutropha H16, when adsorbed at a graphite electrode, exhibits rapid electrocatalytic oxidation of hydrogen that is completely unaffected by carbon monoxide [at 0.9 bar (1 bar = 100 kPa), a 9-fold excess] and is inhibited only partially by oxygen. The practical significance of this discovery is illustrated with a simple fuel cell device, thus demonstrating the feasibility of future hydrogen-cycle technologies based on biological or biologically inspired electrocatalysts having high selectivity for hydrogen.
Footnotes
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↵ § To whom correspondence should be addressed. E-mail: fraser.armstrong{at}chem.ox.ac.uk.
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Author contributions: K.A.V., O.L., B.F., and F.A.A. designed research; K.A.V., J.A.C., O.L., and I.Z. performed research; K.A.V. and J.A.C. analyzed data; and K.A.V. and F.A.A. wrote the paper.
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Conflict of interest statement: No conflicts declared.
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This paper was submitted directly (Track II) to the PNAS office.
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Abbreviations: Av, Allochromatium vinosum; Dg, Desulfovibrio gigas; MBH, membrane-bound hydrogenase; Re, Ralstonia eutropha; Tv, Trametes versicolor.
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See Commentary on page 16911.
- Copyright © 2005, The National Academy of Sciences
