Abstract
The combination of enzymes with semiconductors enables the photoelectrochemical characterization of electron-transfer processes at highly active and well-defined catalytic sites on a light-harvesting electrode surface. Herein, we report the integration of a hydrogenase on a TiO(2)-coated p-Si photocathode for the photo-reduction of protons to H(2). The immobilized hydrogenase exhibits activity on Si attributable to a bifunctional TiO(2) layer, which protects the Si electrode from oxidation and acts as a biocompatible support layer for the productive adsorption of the enzyme. The p-Si|TiO(2)|hydrogenase photocathode displays visible-light driven production of H(2) at an energy-storing, positive electrochemical potential and an essentially quantitative faradaic efficiency. We have thus established a widely applicable platform to wire redox enzymes in an active configuration on a p-type semiconductor photocathode through the engineering of the enzyme-materials interface.