title: Efficient photocatalytic hydrogen evolution without an electron mediator using a simple electron donor-acceptor dyad.
abstract: A highly efficient photocatalytic hydrogen evolution system without an electron mediator such as methyl viologen (MV(2+)) has been constructed using 9-mesityl-10-methylacridinium ion (Acr(+)-Mes), poly(N-vinyl-2-pyrrolidone)-protected platinum nanoclusters (Pt-PVP) and NADH (beta-nicotinamide adenine dinucleotide, reduced form) as the photocatalyst, hydrogen evolution catalyst and electron donor, respectively. The photocatalyst (Acr(+)-Mes) undergoes photoinduced electron transfer (ET) from the Mes moiety to the singlet excited state of the Acr(+) moiety to produce an extremely long-lived ET state, which is capable of oxidizing NADH and reducing Pt-PVP, leading to efficient hydrogen evolution. The hydrogen evolution efficiency is 300 times higher than that in the presence of MV(2+) because of the much faster reduction rate of Pt-PVP by Acr(*)-Mes compared with that by MV(*+). When the electron donor (NADH) is replaced by ethanol in the presence of an alcohol dehydrogenase (ADH), NADH is regenerated during the photocatalytic hydrogen evolution.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kotani
authors.forename: Toshiya
authors.initials: T
authors.lastname: Ono
authors.forename: Kei
authors.initials: K
authors.lastname: Ohkubo
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
mesh_terms: D002384:Catalysis; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry
chemical_list: D006859:Hydrogen