Electro-assembly of a Chromophore-Catalyst Bilayer for Water Oxidation and Photocatalytic Water Splitting

The use of electropolymerization to prepare electrocatalytically and photocatalytically active electrodes for water oxidation is described. Electropolymerization of the catalyst Ru-II(bda)(4-vinylpyridine)(2) (bda=2,2-bipyridine-6,6-dicarboxylate) on planar electrodes results in films containing semirigid polymer networks. In these films there is a change in the water oxidation mechanism compared to the solution analogue from bimolecular to single-site. Electro-assembly construction of a chromophore-catalyst structure on mesoporous, nanoparticle TiO2 films provides the basis for a dye-sensitized photoelectrosynthesis cell (DSPEC) for sustained water splitting in a pH7 phosphate buffer solution. Photogenerated oxygen was measured in real-time by use of a two-electrode cell design.