▎ 摘　　要

By using sulfonated graphene as a support for the platinum (Pt) cocatalyst, a new water-soluble composite (GSO(3)Pt) characteristic of small-sized and "clean'' Pt nanoparticles on graphene was prepared by a facile photoreduction method, in which Hantzsch 1,4-dihydropyridine (HEH) was used as a reductant. The photocatalytic system, containing eosin Y (EY) as a sensitizer, GSO(3)Pt as a catalyst, and TEOA as a sacrificial electron donor, exhibited an 18 times increase in hydrogen (H-2) production compared to when colloidal Pt rather than GSO(3)Pt was used to conduct the same photocatalytic reaction. The higher turnover number (TON), up to 6410 +/- 770 based on platinum, is attributed to the efficient forward electron-transfer mediated by graphene, which was clearly verified for the first time by using the unique spectroscopic property of EY.