A polypyridyl ruthenium sensitizer possessing pyridyl anchors (Ru-py) forms much stronger chemical linkages to TiO surfaces compared to the conventional carboxylate and phosphonate ones. A highly stable dye-sensitized photoelectrochemical cell for water reduction is successfully demonstrated using this technique.

The onset potential for H production from neutral water (pH 7) catalyzed by a platinum(ii) porphyrin (PtP-py) modified TiO electrode positions very close to the standard water reduction potential (less than 50 mV). H production is driven by the conduction band edge potential of TiO at the PtP-py-modified TiO cathode.