Photosensitization of different ruthenium(II) complex dyes on TiO2 for photocatalytic H2 evolution under visible-light

Hydrogen production over dye-sensitized Pt/P25 under visible-light irradiation was investigated by using methanol or TEOA as an electron donor. Ru 2 (bpy) 4 L 1 –PF 6 shows the best photosensitization due to its largest conjugation system, widest range of visible-light and ‘antenna effect’ among the used three Ru(II)-bipyridyl dyes. Ru 2 (bpy) 4 L 1 –PF 6 loosely linked with TiO 2 also exhibit more steady and higher increases in H 2 evolution upon prolonging the irradiation time than the tightly linked N719. The dynamic equilibrium between the linkage of ground dye and divorce of oxidized dye from TiO 2 can enhance the electron-injection and hinder the backward transfer, and then improve the H 2 evolution efficiency.