title: Towards a comprehensive insight into efficient hydrogen production by self-assembled Ru(bpy)3(2+)-polymer-Pt artificial photosystems.
abstract: The role of polymers in artificial photosystems has been studied in detail. The photosystems were composed of tris(2,2'-bipyridyl) ruthenium(II) chloride as a photosensitizer (PS), colloidal Pt stabilized by polymer as a hydrogen-evolving catalyst and sodium ascorbate as an electron donor, without the addition of a traditional molecular electron mediator. Comprehensive insights into the production of hydrogen on irradiation with visible light were achieved. Several polymers, including neutral polyvinyl pyrrolidone, anionic poly(sodium 4-styrene sulfonate) and poly(acrylic acid) not only stabilized the nanoparticles, but were also effective in the production of hydrogen. Under the optimum conditions, an outstanding apparent quantum efficiency of 12.8% for the evolution of hydrogen was achieved. The formation of self-assembled and spatially separated donor-acceptor complexes via the non-covalent intermolecular interaction between PS and the polymer-Pt was pivotal in the efficient conversion of solar energy to hydrogen fuel. Important details of the photo-induced electron and energy transfer processes in the self-assembled artificial photosystems were determined by nanosecond transient absorption spectrometry and time-resolved fluorescence spectrometry. The initial step in the photo-catalytic production of hydrogen was a reductive quenching of the triplet excited state of the PS by sodium ascorbate, leading to a reduced form of PS, which could then be quickly quenched by the polymer. The rate-determining step was the electron transfer from PS to the catalyst via the polymer bridge.
authors: State Key Laboratory of Photocatalysis on Energy and Environment, School of Chemistry, Fuzhou University, Fuzhou 350116, P. R. China. jllong@fzu.edu.cn xwang@fzu.edu.cn.
authors: Huan
authors: H
authors: Lin
authors: Dan
authors: D
authors: Liu
authors: Jinlin
authors: J
authors: Long
authors: Zizhong
authors: Z
authors: Zhang
authors: Huaqiang
authors: H
authors: Zhuang
authors: Yi
authors: Y
authors: Zheng
authors: Xuxu
authors: X
authors: Wang
mesh_terms: D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives* / Q000737:chemistry; D001205:Ascorbic Acid / Q000737:chemistry; D002384:Catalysis; D056831:Coordination Complexes; D004579:Electron Transport; D006859:Hydrogen / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D055668:Photochemical Processes; D010984:Platinum / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D017975:Ruthenium Compounds
chemical_list: D015082:2,2'-Dipyridyl; D001205:Ascorbic Acid; D056831:Coordination Complexes; D006859:Hydrogen; D010984:Platinum; D011108:Polymers; C547232:tris(2,2-bipyridine)-ruthenium(II); D017975:Ruthenium Compounds