Bio-inspired model of photosystem II: supramolecular assembly of an electron mediator into an SnO₂ photoanode co-sensitized by a porphyrin photosensitizer and ruthenium molecular catalyst

A bio-inspired electron transfer mediator was incorporated via a Zr⁴⁺ ion linkage into a photoanode assembled from a porphyrin photosensitizer displaying broad spectral coverage in the visible region and a ruthenium water oxidation catalyst. Incorporation of the electron mediator suppressed unwanted charge recombination and facilitated the transfer of charge from aqueous electrolyte to the photoanode, resulting in an increase in the photocurrent. A remarkable enhancement of faradaic efficiency for oxygen evolution upon introduction of the mediator was observed in the photoelectrochemical cell.