能带结构可调控的配位聚合物的设计合成与光催化性能

The project aims to develop the coordination polymer photocatalytic materials with high activities, high stability, and tunable band structures under visible light irradiation. According to the relationships among electron structures of the metals, element electronegativities, and electronic energy bands, combining with calculations of quantum chemistry, a series of coordination polymer photocatalysts will be expected to be designed and synthesized by the bottom-up self-assembly of the as-prepared building units, based on the weak interactions of the coordinate, hydrogen, and reversible covalence bonds between the suitable metals and multi-functional organic ligands. This approach will be guided under the crystal engineering and supermolecule chemistry principles. Furthermore, by modifying the ligands with different substituent groups and different d-electron metals, the band structures (HOMO and LUMO) of the as-prepared coordination polymers will be tuned. Thus, these materials are efficiently activated under visible light irradiation and their energy bands will be adjusted to correspond with the redox potential of reactive molecules. The self-assembly synthesis rules of the coordination polymer photocatalysts will be explored and summarized. We will try to unravel the relationships among the components, crystal structures, electronic structures, electron and space effects of ligands, and photocatalytic activities. The mobilities of photogenerated electron-hole pairs and the activated mechanisms of the reactive molecules will also be researched. Then the possible models of photocatalysis will be proposed and established. Finally, the novel visible light-drived photocatalysts with high quantum yield are expected to be developed and a possible theory for the guidance of designing coordination polymer photocatalysts may be revealed and proposed. It is of significant values for the study on this project in both theory and experiment for deeply understanding the intrinsic nature of photocatalysis from molecule level.

以发展高效稳定的、具有可调控能带结构的配位聚合物光催化材料为目标，结合量子化学的计算，选择合适的金属和有机配体，运用晶体工程和超分子化学原理，从构筑基元出发，通过配位键、氢键、可逆共价键等弱相互作用，同时采用不同键合力的配体、配体中芳环上不同诱导性和共轭特征的取代基以及不同d电子的金属等修饰方法，来实现对配位聚合物的能带结构的调控.使之既能有效吸收可见光又能与反应物分子的能级相匹配，从而完成高效稳定的可见光响应的新型配位聚合物光催化材料的设计合成。探索和总结这类材料的自组装合成规律，揭示其组成、晶体结构、电子能级结构、配体电子和空间效应与其光催化性能之间的关系，研究光生电子迁移行为和对反应物分子的活化机制，建立其可能的光催化反应机理模型，提出指导设计具有高效可见光光催化性能的配位聚合物的可能理论，为从分子水平深入理解光催化的本质以及开发研制高效新型光催化材料奠定理论和实验基础。

本项目通过选择合适的金属和有机配体，运用晶体工程和超分子化学原理，从构筑基元出发制备了系列高效稳定的、具有可调控能带结构的配位聚合物光催化材料，例如UiO-66, UiO-66(NH2), UiO-66(SH)2, MIL-125(Ti), MIL-125(Ti)-NH2, MIL-68(In), MIL-68(In)-NH2, MIL-53(Fe), MIL-68(Fe), MIL-100(Fe)。此外，利用MOFs大比表面积、多孔性等结构特点，构筑了系列MOFs基的新型复合光催化材料，如Pd@UiO-66(NH2), M/MIL-125(Ti) (M = Au, Pd, Pt), Pd@MIL-100(Fe), M@MIL-100(Fe) (M = Au, Pd, Pt), RGO@UiO-66(NH2), RGO@MIL-53(Fe), UiO-66/CdS, MIL-125/CdS, CdS@MIL-68(Fe), HPMo@MIL-100(Fe), ZnIn2S4/UiO-66, MoS2/UiO-66/CdS, UiO-66/CdS/GR。它们在环境光催化反应中如有机染料降解、重金属还原、产氢、有机物选择性氧化等表现出较高的光催化活性和催化活性稳定性。探索和总结了这类材料的自组装合成规律，揭示其组成、晶体结构、电子能级结构、配体电子和空间效应与其光催化性能之间的关系，建立了可能的光催化反应机理模型。这些研究结果将对MOFs基光催化剂的制备、能带调控以及从分子水平认识光催化作用奠定理论和实验基础。