Nickel Complexes for Robust Light-Driven and Electrocatalytic Hydrogen Production from Water
摘要:
A series of nickel bis(chelate) complexes having square planar coordination are studied for light-driven and electrocatalytic hydrogen production from water. The complexes Ni(abt)2 (abt = 2-aminobenzenethiolate), Ni(mp)(2) (mp = 2-mercaptophenolate) and Ni(mpo)(2) (mpo = 2-mercaptopyridyl-N-oxide) are found to be active catalysts under light-driven conditions, using fluorescein (Fl) as the photosensitizer (PS) and triethanolamine (TEOA) as the sacrificial electron donor in water under basic pH (pH = 9.8). These molecular systems achieve a turnover number (TON) of similar to 6000 (relative to catalyst) and are stable for more than 100 h under H-2-generating conditions. When water-soluble CdSe quantum dots with tripodal S-donor capping agents are employed as PS and ascorbic acid (AA) is used as the sacrificial electron donor at pH 4.5, an active and robust system is obtained for the light-driven generation of H-2 from aqueous protons. A TON of over 280 000 is achieved for the three active catalysts. These complexes are also examined electrochemically in organic solvents with weak organic acids as the proton source and in aqueous and aqueous/organic media for proton reduction. The most active photochemical catalysts also show excellent electrocatalytic activity in neutral pH water, achieving Faradaic yields close to 100% under anaerobic conditions and similar to 80% under aerobic conditions.
Nickel Complexes for Robust Light-Driven and Electrocatalytic Hydrogen Production from Water
摘要:
A series of nickel bis(chelate) complexes having square planar coordination are studied for light-driven and electrocatalytic hydrogen production from water. The complexes Ni(abt)2 (abt = 2-aminobenzenethiolate), Ni(mp)(2) (mp = 2-mercaptophenolate) and Ni(mpo)(2) (mpo = 2-mercaptopyridyl-N-oxide) are found to be active catalysts under light-driven conditions, using fluorescein (Fl) as the photosensitizer (PS) and triethanolamine (TEOA) as the sacrificial electron donor in water under basic pH (pH = 9.8). These molecular systems achieve a turnover number (TON) of similar to 6000 (relative to catalyst) and are stable for more than 100 h under H-2-generating conditions. When water-soluble CdSe quantum dots with tripodal S-donor capping agents are employed as PS and ascorbic acid (AA) is used as the sacrificial electron donor at pH 4.5, an active and robust system is obtained for the light-driven generation of H-2 from aqueous protons. A TON of over 280 000 is achieved for the three active catalysts. These complexes are also examined electrochemically in organic solvents with weak organic acids as the proton source and in aqueous and aqueous/organic media for proton reduction. The most active photochemical catalysts also show excellent electrocatalytic activity in neutral pH water, achieving Faradaic yields close to 100% under anaerobic conditions and similar to 80% under aerobic conditions.
The strong proton-electron coupling behavior of a π-planar nickel(II) complex with redox-active N,S-ligands was demonstrated using optical and electrochemical methods as well as theoretical calculations. The potential-pH diagram shows a significant shift in the acidity-dependent redox potential, which is supported by the calculated energetic stabilization of frontier orbitals by protonation.
使用光学和电化学方法以及理论计算证明了具有氧化还原活性 N,S-配体的 π 平面镍 (II) 配合物的强质子 - 电子耦合行为。电位-pH 图显示了酸度依赖性氧化还原电位的显着变化,这得到了通过质子化计算的边界轨道的能量稳定性的支持。
Nickel(IV)-Komplexe und ihre Bedeutung bei der Bildung des Carbonyls
作者:W. Hieber、R. Br�ck
DOI:10.1007/bf00590333
日期:——
Hieber, W.; Brueck, R., Zeitschrift fur Anorganische und Allgemeine Chemie