含有{Fe4O4}等立方烷结构的仿生多酸放氧催化剂设计合成与催化性能研究

学习和借鉴自然光合作用Mn4CaO5团簇，研制仿生水裂解放氧催化剂具有重要的科学意义和潜在的应用价值。含立方烷单元{M4O4}结构类似于Mn4CaO5中心的部分多酸表现出很好的放氧性能，前期报道主要集中于活性位点是Mn、Co、Ni的立方烷多酸催化剂。位于同一周期的Fe、Cu、V构成的立方烷多酸是否具有放氧活性尚不清楚。前期我们在钴基立方烷多酸以及非立方烷多酸放氧催化剂方面开展了许多研究，本项目拟在此基础上设计合成含有立方烷结构单元{Fe4O4}、{Cu4O4}、{V4O4}和{Nb4O4}或片段且具有放氧活性的新型多酸分子催化剂。采用简单金属盐与多酸配体直接组装以及缺位多酸配体与本身已含有立方烷结构单元的多酸进行组装调控来合成，揭示立方烷多酸的合成规律以及放氧性能构效关系的本质。通过光谱学、电化学等方法建立多酸光催化放氧反应的机理。为模拟自然光合作用放氧催化中心提供新的范例与借鉴。

The photosynthetic Mn4CaO5cluster in PS II of plant is the sole biocatalyst that makes use of solar energy to split water efficiently and safely, releasing electrons, protons and oxygen. Learning from this organism Mn4CaO5 cluster and developing bionic water cracking catalyst has important scientific significance and potential application value. It is also an important and challenging scientific frontier. Polyoxometalates (POMs) containing {M4O4} cubic structural units that are similar with Mn4CaO5cluster are good biomimetic water oxidation catalysts and their active sites are mainly concentrated in Mn, Co and Ni metals. In the early stage, we carried out a lot of research on cobalt-based cubic POMs and non-cubic POMs water oxidation catalysts. On this basis, this project intends to design and synthesize new POM molecular catalysts with oxygen-producing activity containing cubic alkane structural units {Fe4O4}、{Cu4O4}、{V4O4} and {Nb4O4} or fragments. The synthesis strategy adopts the direct assembly of simple metal salts and POM ligands. Another route is the lacunary POM ligands are assembled with POMs that already contained cubic units. The synthesis of cubic POMs and the nature of the structure-activity relationship of oxygen-producing properties will be revealed. The mechanism of photocatalytic water oxidation of POM molecular catalysts will be established through various spectral characterization, electrochemical methods and theoretical calculation. The implementation of the project will provide a new example for the oxygen-releasing catalytic center of natural photosynthesis.