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Charge transfer between photosynthetic proteins and hematite in bio-hybrid photoelectrodes for solar water splitting cells

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Faccio Greta, Gajda-Schrantz Krisztina, Ihssen Julian, Boudoire Florent, Hu Yelin, Mun Bongjin Simon, Bora Debajeet K., Thony-Meyer Linda, Braun Artur,
Project Fundamental Aspects of Photocatalysis and Photoelectrochemistry / Basic Research Instrumentation for Functional Characterization
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Original article (peer-reviewed)

Volume (Issue) 2
Page(s) 9
Title of proceedings NANO CONVERGENCE
DOI 10.1186/s40580-014-0040-4

Open Access


Functionalization of the hematite photoanode with the photosynthetic light antenna protein C-phycocyanin (PC) can yield substantial enhancement of the photocurrent density. Photoelectrochemical cells with bio-hybrid electrodes from photosynthetic proteins and inorganic semiconductors have thus potential for the use in artificial photosynthesis. We investigate here processing routes for the functionalization of hematite photoanodes with PC, including in situ co-polymerization of PC with enzymatically-produced melanin, and using a recombinant PC genetically engineered to carry a hexa-histidine tag (alpha HisPC). First, the effect of the immobilisation of PC on the electrode morphology and photocurrent production is evaluated. Then, the electronic charge transfer in dark and light conditions is assessed with electrochemical impedance spectroscopy and valence band (VB) X-ray photoemission spectroscopy. The relative shift of the VB spectrum towards the Fermi energy E-F upon illumination is smaller for the more complex processed coating and virtually disappears for alpha HisPC immobilised with a melanin film. Optimal conditions for protein immobilisation are determined and the dark currents benefit most from the most advanced protein coating processes.