Triplet state photosensitization of nanocrystalline metal oxide electrodes by zinc-substituted cytochrome c: application to hydrogen evolution.
The interfacing of nanostructured semiconductor photoelectrodes with redox proteins is an innovative approach to the development of artificial photosynthetic systems. In this paper, we have investigated the photoinduced electron-transfer reactions of zinc-substituted cytochrome c, ZnCyt-c, immobilized on mesoporous, nanocrystalline metal oxide electrodes. Efficient electron injection from the triplet state of ZnCyt-c is observed into TiO(2) electrodes (t(50%) approximately 100 micros) resulting in a long-lived charge-separated state (lifetime of up to 0.4 s). Further studies were undertaken as a function of electrolyte pH and metal oxide employed. Optimum yield of a long-lived charge-separated state was observed employing TiO(2) electrodes at pH 5, consistent with our previous studies of analogous dye-sensitized metal oxide electrodes. The addition of EDTA as a sacrificial electron donor to the electrolyte resulted in efficient photogeneration of molecular hydrogen, with a quantum yield per one absorbed photon of 10 +/- 5%.
Astuti
Yeni
Y
Department of Chemistry, Imperial College London, London SW7 2AZ, UK.
Palomares
Emilio
E
Haque
Saif Ahmed
SA
Durrant
James Robert
JR
D003460:Crystallization; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism; D004492:Edetic Acid / Q000737:chemistry; D004566:Electrodes; D004579:Electron Transport; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008670:Metals / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D011522:Protons; D014025:Titanium / Q000737:chemistry
D004800:Enzymes, Immobilized; D008670:Metals; D010087:Oxides; D011522:Protons; C050095:zinc cytochrome c; C009495:titanium dioxide; D006859:Hydrogen; D045304:Cytochromes c; D004492:Edetic Acid; D014025:Titanium