Photoelectrochemical H$_{2}$ Evolution with a Hydrogenase Immobilized on a TiO$_{2}$-Protected Silicon Electrode

Abstract

The integration 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. Here, we report the integration of a hydrogenase on a TiO$_{2}$-coated p-Si photocathode for the photoreduction 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 biocompatible support layer for the productive adsorption of the enzyme. The p-Si|TiO$_{2}$|hydrogenase photocathode displays the visible-light driven production of H$_{2}$ at an energy-storing, positive electrochemical potential and an essentially quantitative faradaic efficiency. We have therefore 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.