title: Light-driven water splitting for (bio-)hydrogen production: photosystem 2 as the central part of a bioelectrochemical device.
abstract: To establish a semiartificial device for (bio-)hydrogen production utilizing photosynthetic water oxidation, we report on the immobilization of a Photosystem 2 on electrode surfaces. For this purpose, an isolated Photosystem 2 with a genetically introduced His tag from the cyanobacterium Thermosynechococcus elongatus was attached onto gold electrodes modified with thiolates bearing terminal Ni(II)-nitrilotriacetic acid groups. Surface enhanced infrared absorption spectroscopy showed the binding kinetics of Photosystem 2, whereas surface plasmon resonance measurements allowed the amount of protein adsorbed to be quantified. On the basis of these data, the surface coverage was calculated to be 0.29 pmol protein cm(-2), which is in agreement with the formation of a monomolecular film on the electrode surface. Upon illumination, the generation of a photocurrent was observed with current densities of up to 14 microA cm(-2) . This photocurrent is clearly dependent on light quality showing an action spectrum similar to an isolated Photosystem 2. The achieved current densities are equivalent to the highest reported oxygen evolution activities in solution under comparable conditions.
authors.affiliation: Plant Biochemistry, Faculty of Biology, Ruhr-University Bochum, D-44780 Bochum, Germany.
authors.forename: Adrian
authors.initials: A
authors.lastname: Badura
authors.forename: Berndt
authors.initials: B
authors.lastname: Esper
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ataka
authors.forename: Christian
authors.initials: C
authors.lastname: Grunwald
authors.forename: Christof
authors.initials: C
authors.lastname: Wöll
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kuhlmann
authors.forename: Joachim
authors.initials: J
authors.lastname: Heberle
authors.forename: Matthias
authors.initials: M
authors.lastname: Rögner
mesh_terms: D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D006859:Hydrogen / Q000378:metabolism*; D007700:Kinetics; D008027:Light; D010777:Photochemistry; D045332:Photosystem II Protein Complex / Q000378:metabolism* / Q000528:radiation effects; D046940:Synechococcus / Q000378:metabolism* / Q000528:radiation effects; D014867:Water / Q000378:metabolism*
chemical_list: D045332:Photosystem II Protein Complex; D014867:Water; D006859:Hydrogen