基于单核、双核钴配合物的光驱动水氧化分子体系

Light driven water oxidation is considered as the holy grail in artificial photosynthesis II, because it is a chemically challenging and energy demanding process that involves four one-electron oxidation steps which are coupled to the removal of four protons and the formation of the O-O bond. Constructing water oxidation system based on stable and efficient but cheaper and earth-abundant elements is promising, valuable and could bring the idea of artificial photosynthesis to a new level. In this proposal, we intend to design and synthesize a series of functional mono-nuclear and di-nuclear cobalt catalysts in order to reveal the cofactors affecting their stability and efficiency in photo-induced water oxidation. Simultaneously, we will summarize the synthetic strategy of cobalt catalysts associated with the design of organic ligands. Moreover, a dyad featured with linkage between photosensitizer and catalytic centers will hopefully accelerate the electron transfer from catalyst to the oxidized photosensiter and achieve better catalytic performance. In addition, an available device can be obtained through functional photosensitizer and catalyst or dyad anchoring on the surface of FTO|TiO2, which will be then incorporated into a light-driven cell for efficient water oxidation.

模拟自然界的光合系统II（PS II）释放氧气的过程需要连续转移4个电子和4个质子，同时伴随化学键的断裂与生成，是实现水裂解的瓶颈。开发稳定性高、催化性能优越的廉价催化剂具有重要的理论意义和应用前景。本项目拟通过设计合成系列化、功能化的单核、双核钴催化剂，揭示影响其光催化性能和稳定性的因素，提出配体设计、催化剂合成的具体思路。同时，设计合成光敏剂与催化剂相连的二元光驱动水氧化分子催化剂，通过提高光敏中心与催化剂之间的电子转移增强体系的催化效率，并进一步将光敏剂与催化剂或二元光驱动分子催化剂负载于FTO|TiO2表面，构筑光驱动水氧化反应池，利用光电化学分子器件实现水的高效氧化。

以廉价金属为催化剂实现水分解是目前研究的热点问题。开发稳定性高、催化性能优越的廉价催化剂，研究催化机理是主要的发展方向。本项目通过配体设计合成了一系列具有较高活性的金属钴分子催化剂，用于光驱动或电化学水氧化，揭示影响其光催化性能和稳定性的因素，提出配体设计、催化剂合成的具体思路；同时合成了多吡啶铜分子催化剂，首次拓展了铜配合物在光驱动水氧化领域的应用，并进一步将其负载于FTO|TiO2表面，构筑光驱动水氧化反应池，利用光电化学分子器件实现水的分解。此外合成了平面型的多吡啶配体，并将其进一步与铜配位得到了结构新颖的铜配合物，研究表明此化合物在中性条件下具有较高的水分解产氢特性，且催化剂具有较高的稳定性。于此同时，我们又设计合成了[N2O2]型多吡啶铜配合物，此化合物在中性水溶液中展现出稳定的电催化产氢性能，并通过控制电位电解，在玻碳电极表面形成致密的铜催化产氢膜，表征实验表明，[N2O2]配体对催化剂的稳定性及催化性能起到至关重要的作用。