Influence of Ru(II) Bipyridyl Complex on the Photocatalytic H2 Evolution over TiO2 Nanoparticles with Mesostructures

H2 production over dye-sensitized Pt/TiO2 nanoparticles with mesostructures under visible light was investigated by using methanol as electron donors. Three types of Ru(II) bipyridyl complexes, which can be attached to Pt/m-TiO2 with different linkage modes, show different photosensitization. The dye tightly linked with m-TiO2 has better durability but the lowest H2 evolution efficiency, whereas the loosely attached dyes possess higher H2 evolution efficiency and preferable durability. It seems that the dynamic equilibrium between the linkage of ground state dye with TiO2 and the divorce of oxidization state dye from the surfaces plays a crucial role in the photochemical behavior during photocatalyst sensitization process. The binuclear Ru(II) shows a better photosensitization in comparison with mono- nuclear Ru(II) dyes due to its large conjugation system and “antenna effect”, which, in turn, improve the visible light harvesting and electron transfer between the dye and TiO2.