以多酸为模板构筑高核钛氧簇合物及其光催化制氢研究

As the molecular model of technically important TiO2 materials, structurally well-defined polyoxotitanium clusters (PTCs) have attracted wide attentions due to their excellent photocatalytic activities. High-nuclearity PTCs are regarded as ideal structure models for TiO2 and exhibit high photocatalytic activities because of their comparable sizes to nanoscale TiO2. However, facile synthesis of high-nuclearity PTCs is still very challenging. In this project, we propose to set up a new synthetic strategy for high-nuclearity PTCs by using superlacunary polyoxometalates (POMs) and their cyclic oligomers as templates. The POM templates will be introduced into organic phases and both the oxygen atoms on lacunary sites and surface terminal oxygen atoms will be used to assemble with different titanium precursors and organic ligands, aiming to construct a series of novel POM-templated PTCs with good crystallinity. The underlying mechanism of the self-assembly of prepared PTCs will be studied by a variety of spectroscopic methods. Their photocatalytic activity towards hydrogen evolution will be optimized by tuning the structures and electronic properties of organic ligands and POM templates, and the influence of structural features on the catalytic performance will also be summarized, which will lead to the discovery of novel high-nuclearity PTCs with high activity for hydrogen evolution. It is expected that this project will promote the application of POMs in the cluster synthesis as well as the development of POM chemistry and titanium-oxo cluster chemistry.

作为二氧化钛结构和性能的分子模型化合物，结构明确的钛氧簇合物在光催化领域得到了广泛的关注。高核钛氧簇合物因其尺寸与纳米二氧化钛接近，因此成为研究二氧化钛的优良结构模型并展现出高的光催化效果。然而，制备此类高核钛氧簇合物依然是该领域的一大挑战。本项目拟开发出合成高核钛氧簇合物的新型制备方法，通过采用高缺位多酸及自聚形成的环状多酸作为模板，在有机相中利用其多个活性缺位氧和表面端基氧与多种钛源和有机配体进行自组装，制备出一系列结构新颖并具有优良结晶性能的高核钛氧簇合物。利用多种谱学手段研究高核钛氧簇合物的自组装机理，通过有机配体和多酸模板结构和电子性能上的调控优化光解水制氢的性能，探索并总结其构效关系，开发具有高效光解水制氢活性的新型高核钛氧簇合物。预期本项目将促进多酸在团簇合成中的应用，并推动多酸化学和钛氧簇化学的发展。

本项目针对作为纳米二氧化钛模拟物的高核钛氧簇的高效制备及光催化析氢性能进行了探索研究，基于多酸作为模板，同时利用有机配体导向、异金属掺杂以及异金属和配体供导向合成策略，制备了系列高核钛氧簇以及光活性钛氧簇。系统研究了簇合物的光电性能，重点探索了多酸模板、配体结构和取代基团、异金属配位模式和电子构型以及簇核结构对光电性能的调控，筛选出多种具有较窄带隙和高光电流响应的钛氧簇，深入研究了其在光解水析氢方面的应用。主要在以下几方面取得系列研究成果：（1）异金属掺杂策略构建钛氧簇及其光催化析氢性能研究；（2）配体导向策略构建新型钛氧簇及光催化析氢性能研究，主要包括光敏配体功能化、混合配体导向以及阴离子调控等合成方法；（3）异金属和配体共同导向构建新型钛氧簇及光电性能研究；（4）多酸模板导向构建笼状钛氧簇超分子框架。系统研究了钛氧簇结构和光催化性能之间的关系，为今后精准制备具有特定结构和优异光解水制氢的高核钛氧簇提供了理论和实验依据。作为本项目标注的研究成果， Chin. Chem. Lett., Inorg. Chem. Front., Dalton Trans. 等杂志上发表高质量 SCI 论文 5 篇。