Biocatalysts for fuel cells: efficient hydrogenase orientation for H2 oxidation at electrodes modified with carbon nanotubes
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We report the modification of gold and graphite electrodes with commercially available carbon nanotubes for immobilization of Desulfovibrio fructosovorans [NiFe] hydrogenase, for hydrogen evolution or consumption. Multiwalled carbon nanotubes, single-walled carbon nanotubes (SWCNs), and amine-modified and carboxyl-functionalized SWCNs were used and compared throughout. Two separate methods were performed: covalent attachment of oriented hydrogenase by controlled architecture of carbon nanotubes at gold electrodes, and adsorption of hydrogenase at carbon-nanotube-coated pyrolytic graphite electrodes. In the case of self-assembled carbon nanotubes at gold electrodes, hydrogenase orientation based on electrostatic interaction with the electrode surface was found to control the electrocatalytic process for H2 oxidation. In the case of carbon nanotube coatings on pyrolytic graphite electrodes, catalysis was controlled more by the geometry of the nanotubes than by the orientation of the enzyme. Noticeably, shortened SWCNs were demonstrated to allow direct electron transfer and generate high and quite stable current densities for H2 oxidation via adsorbed hydrogenase, despite having many carboxylic surface functions that could yield unfavorable hydrogenase orientation for direct electron transfer. This result is attributable to the high degree of oxygenated surface functions in addition to the length of shortened SWCNs that yields highly divided materials.
KeywordsVoltammetry Hydrogenase Carbon nanotube Immobilization Catalysis
Atomic force microscopy
Direct electron transfer
Multiwalled carbon nanotube
Single-walled carbon nanotube
Carboxylic acid functionalized single-walled carbon nanotube
Shortened single-walled carbon nanotube
Transmission electron microscopy
The authors would like to thank M. Rousset (Bioenergetic et Ingenierie des Proteines-CNRS, France) for helpful discussions, A. Cornish-Bowden and M. L. Cardenas for critical reading of the manuscript, J. P. Chauvin (Institut de Biologie du Développement de Marseille Luminy, France), and Damien Chaudanson (Centre Interdisciplinaire de Nanoscience de Marseille, France) for TEM observations, and Biophy Research (Fuveau-France) for AFM observations.
- 4.Vincent KA, Cracknell JA, Parkin A, Armstrong FA (2005) Dalton Trans 3397–3403Google Scholar
- 15.Gooding JJ, Shapter JG (2005) In: Vo-Dinh T (ed) Protein nanotechnology: protocols, instrumentation, and applications (methods in molecular biology). Humana Press, New York, pp 225–242Google Scholar
- 32.Barisci JN, Wallace GG, Baughman RH (2000) J Electrochem Soc 488:92–98Google Scholar