Hydrogen Production from Hydrophobic Ruthenium Dye-Sensitized TiO Photocatalyst Assisted by Vesicle Formation.

Dye-sensitized H evolution photocatalysts have attracted considerable attention as promising systems for the photochemical generation of H from water. In this study, to mimic the reaction field of natural photosynthesis artificially, we synthesized a hydrophobic Ru(II) dye-sensitized Pt-TiO nanoparticle photocatalyst, @Pt-TiO ( = [Ru(dCbpy)(Hdmpbpy)]; dCbpy = 4,4'-dinonyl-2,2'-bipyridine, Hdmpbpy = 4,4'-dimethyl phosphonic acid-2,2'-bipyridine), and integrated it into 1,2-dipalmitoyl--glycero-3-phosphocholine (DPPC) lipid bilayer vesicle membranes. The photocatalytic H production activity in 0.5 M l-ascorbic acid aqueous solution enhanced by more than three times in the presence of DPPC vesicles (apparent quantum yield = 2.11%), whereas such a significant enhancement was hardly observed when the vesicle formation was omitted. These results indicate that the highly dispersed state of the hydrophobic @Pt-TiO nanoparticles in the DPPC bilayer vesicles is a key factor in achieving enhanced photocatalytic H production activity in aqueous solution.