Artificial photosynthesis--functional devices for light driven water splitting with photoactive anodes based on molecular catalysts.

Photoactive anodes consisting of Ru(bpy)3 type photosensitizer 1 and molecular catalysts 2 and 3 on nanostructured TiO2 have been assembled in functional devices for successful light driven water splitting. From their performance measurements we found that the photoanode TiO2(1 + 3) in which the molecular ruthenium catalyst and the phosphonate anchoring group are linked by a flexible –CH2CH2CH2– chain showed a significantly higher photocurrent density than the photoanode TiO2(1 + 2) with only –CH2– linkage. The possible reasons for the different water splitting performance of otherwise identical devices are discussed.