title: Chitosan confinement enhances hydrogen photogeneration from a mimic of the diiron subsite of [FeFe]-hydrogenase.
abstract: Nature has created [FeFe]-hydrogenase enzyme as a hydrogen-forming catalyst with a high turnover rate. However, it does not meet the demands of economically usable catalytic agents because of its limited stability and the cost of its production and purification. Synthetic chemistry has allowed the preparation of remarkably close mimics of [FeFe]-hydrogenase but so far failed to reproduce its catalytic activity. Most models of the active site represent mimics of the inorganic cofactor only, and the enzyme-like reaction that proceeds within restricted environments is less well understood. Here we report that chitosan, a natural polysaccharide, improves the efficiency and durability of a typical mimic of the diiron subsite of [FeFe]-hydrogenase for photocatalytic hydrogen evolution. The turnover number of the self-assembling system increases ~4,000-fold compared with the same system in the absence of chitosan. Such significant improvements to the activity and stability of artificial [FeFe]-hydrogenase-like systems have, to our knowledge, not been reported to date.
authors.affiliation: 1] Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry & University of Chinese Academy of Sciences, the Chinese Academy of Sciences, Beijing 100190, China [2].
authors.forename: Jing-Xin
authors.initials: JX
authors.lastname: Jian
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Xu-Bing
authors.initials: XB
authors.lastname: Li
authors.forename: Cheng-Bo
authors.initials: CB
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Qing-Yuan
authors.initials: QY
authors.lastname: Meng
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.forename: Ke
authors.initials: K
authors.lastname: Feng
authors.forename: Chen-Ho
authors.initials: CH
authors.lastname: Tung
authors.forename: Li-Zhu
authors.initials: LZ
authors.lastname: Wu
mesh_terms: D002384:Catalysis; D020134:Catalytic Domain; D048271:Chitosan / Q000737:chemistry*; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D006864:Hydrogenase / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008027:Light; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D011134:Polysaccharides / Q000737:chemistry; D013997:Time Factors
chemical_list: D007506:Iron-Sulfur Proteins; D011134:Polysaccharides; D006859:Hydrogen; D048271:Chitosan; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase