Irradiation of acidic (pH 2) solutions of RuL32+ 2Cl− (L = diisopropyl 2,2′‐bipyridine‐4,4′ ‐dicarboxylate) in the presence of TiO2 at 100°C leads to the loss of one bipyridyl ligand and the chemical fixation of RuL2 at the surface of teh TiO2 particles through formation of Ru‐O‐Ti bonds. These surface complexes are very stable and shift the absorption onset of TiO2 beyond 600 mm. Efficient sensitization H2‐generation is achieved with this system beginning in the wave length domain between 590 and 665 nm. Preliminary water cleavage experiments with bifunctional TiO2/Pt/RuO2 redox catalyst are reported.
Michael Graetzel, Shaik Mohammed Zakeeruddin, Ladislav Kavan