| Summary: | 碩士 === 國立交通大學 === 生物科技系所 === 101 === Hydrogen, which is renewable and non-polluting, has been considered as an alternative energy to fossil fuel. In nature, hydrogenases (H2ase) can catalyze the reversible oxidation-reduction reaction (2H+ + 2e- ↔ H2) to produce hydrogen. The active site of [FeFe]ase, a dithiolate-bridged diiron complex, called the H-cluster, has been used as a biomimetic photochemical catalyst for light-driven hydrogen production. The goal of the present study is to mimic the structure of H-cluster by substituting the center metal iron with ruthenium. In this research, ruthenium-based H-clusters, [Ru2(CO)6(-S(CH2)3S)] and [(Ru3(CO)10)2(-S(CH2)3S)] are synthesized and characterized by NMR, MS, FT-IR spectroscopy and single crystal X-ray structure determination. The photocatalytic activity of these ruthenium-based H-clusters clusters in hydrogen production is investigated using different proton sources, such as water and formic acid. In addition, we evaluate the effects of a series of electron-donating phosphine ligands additions on the photocatalytic system for hydrogen production. The results show that hydrogen production obtained from formic acid is better than from water. In the organic phase, with formic acid as a proton source, ruthenium-based H-clusters show high efficiency for hydrogen evolution in the presence of P-ligands, and the hydrogen yield obtained from the P-ligands with electron donating functional group is higher than the P-ligands with electron withdrawing functional group. The best turnover frequency (TOF) 116.62 h-1 is observed with [Ru3(CO)10]2[-S(CH2)3S] as the photocatalyst in presence of tris(4-methoxyphenyl)phosphine (P(p-C6H4OMe)3) under Xe lamp (500 W) irradiation. The efficiency of hydrogen production is better than in previous studies. The detailed catalytic mechanism of these artificial biomimetic H-clusters is further discussed. In the future, ruthenium-based H-clusters will be promising catalysts in the light-driven hydrogen production industry.
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