Figure 1.

(a) Schematic representation of the semi-artificial photosynthetic tandem PEC cell coupling CO₂ reduction to water oxidation. A blend of P_Os and PSII adsorbed on a dpp-sensitized photoanode (IO-TiO₂|dpp|P_Os-PSII) is wired to an IO-TiO₂|FDH cathode (species size not drawn to scale). (b) Energy level diagram showing the electron-transfer pathway between PSII, the redox polymer (P_Os), the dye (dpp), the conduction band (CB) of IO-TiO₂ electrodes, four [Fe₄S₄] clusters, and the [WSe]-active site in FDH. All potentials are reported vs SHE at pH 6.5. Abbreviations: Mn₄Ca, oxygen-evolving complex (OEC); P680, pigment/primary electron donor; Q_B, plastoquinone B; [Fe₄S₄], iron–sulfur clusters; [WSe], FDH active site.