基于非贵金属铁的新型高效水氧化催化剂的研发及水氧化催化机理的研究

Artificial photosynthesis is an important and eco-friendly way to convert solar energy into chemical energy hydrogen and to provide a functional model for the design of an efficient artificially photosynthetic molecular device. So far, water oxidation catalysts (WOCs) based on earth-abundant metal are still rare and the catalytic activity is low, and most of the water oxidation reaction was studied in acidic media. However, artificially photosynthetic molecular device usually work in neutral or basic conditions with highly efficient WOCs. Herein, a series of mononuclear iron complexes based on carboxylate substituted N-dentate ligands and binuclear iron complexes based on polypyridyl ligands were synthesized and characterized, and their catalytic activities towards water oxidation were investigated by different methods, and the water oxidation mechanism was studied in neutral and basic media by iron-based catalysts and the reported mononuclear Ru(II)(bda)(L)2 complexes (most efficient mononuclear Ruthenium WOCs). This project try to improve the catalytic activity of WOCs by designing a number of new type iron-based catalysts and provide a functional model for the design of novel molecular WOCs based on earth-abundant metals and an efficient artificial photosynthesis device.

通过人工模拟光合作用构建高活性可见光驱动水氧化分子器件对于实现光解水制氢具有重大意义。目前分子水平的非贵金属水氧化催化剂(WOCs)的数量少、催化转化效率低并且其催化水氧化反应大多在酸性介质中进行，而实际应用中的光解水制氢器件多在中性和碱性介质中，并利用高效的催化剂构建完成。针对这些研究现状，本项目提出将非贵金属铁配合物应用于水氧化反应，并考察一系列基于不同金属的催化剂在中性和碱性介质中的水氧化过程。通过设计合成一系列含有羧基取代基的多齿配体（N-dentate）配位的单核铁配合物及多吡啶配位的双核铁配合物，测试其水氧化催化效率，研究其以及目前活性最高的一类单核钌催化剂Ru(II)(bda)(L)2在中性及碱性介质中的水氧化催化机理，以期克服非贵金属水氧化催化剂数量少，效率低的缺陷，同时为新型高效非贵金属分子催化剂的设计及高效光解水制氢器件的构建积累理论基础。

通过人工模拟光合作用构建高活性可见光驱动水氧化分子器件对于实现光解水制氢具有重大意义。项目围绕光电催化分解水制氢开展研究工作，取得以下创新性成果：为了降低成本，同时开发高效的催化剂，我们设计合成了一种基于廉价过渡金属锰的金属配合物Mn(II)(BQCN)(OTf)2，在光照条件下，可以高效稳定的催化氧化有机底物苄醇和硫醚，并推测了以单核锰配合物作为催化剂时光催化氧化有机底物反应的机理。以含有长碳链的配合物[Ni(C12-tpen)](ClO4)2作为前驱体，通过电沉积手段得到一个几乎透明的薄膜NiFeOxHy。在 1.0 M 氢氧化钾水溶液中，该NiFeOxHy薄膜展示出优异的电催化及光电催化水氧化活性和稳定性，为光催化水分解体系的实际应用提供了重要的参考。以上成果为新型高效非贵金属分子催化剂的设计及高效光解水制氢器件的构建积累理论基础。