苝酰亚胺类有机超分子可见光光催化剂活性机理及其对酚类污染物降解性能研究

Orbital overlaps between monomer molecules and strong electron coupling originated from the ordered intermolecular arrangement and conjugate stacking within the PDI supramolecular system, give rise to the band-like electronic energy structure and appreciable carrier mobility and separation ability of PDI supramolecular photocatalyst. This project intends to tune the nanostructure morphology, electronic energy structure, photo-generated carrier mobility and separation efficiency of PDI supramolecular photocatalyst through the design of monomer molecule structure and regulation of non-covalent bond interactions, eventually realize successful synthesis of PDI supramolecular nanostructures with broad spectral response and high photocatalytic activity. This project would take phenolic substance, which is generally known as key component in the coal chemical industry wastewater, as a target pollutant model, and investigate their photo-oxidative degradation or mineralization process through PDI-based supramolecular photocatalysts. At the same time, this project also devotes to exploring and enhancing the activity of catalyst on splitting water for O2 evolution. Specifically, combined with systematic studies on the reaction routes and catalytic mechanisms of photo-degradation over pollutants and photocatalytic splitting water for O2 evolution, this project also aims to reveal the structure-activity relationship between the catalyst structure (structure at micro scale, electronic energy structure) and photocatalytic activity. In addition, the stabilizing effect on PDI supramolecular system and influence mechanism on its photo-generated carrier mobility and separation ability through coupling of precious metals/carbon materials or metal oxide semiconductor due to their electron capture and export capability would also be explored in detail.

苝酰亚胺(PDI)类有机超分子光催化剂因单体分子的有序排列与共轭堆积而产生分子间波函数重叠及强电子耦合作用，因而呈现出带状电子能级结构及良好的光生载流子迁移性。本项目拟通过单体分子结构设计及调控非共价键相互作用，调控PDI超分子的纳米结构形貌、能带结构及其光生载流子迁移与分离效率，进而可控合成具有宽光谱响应、高活性的PDI超分子光催化剂纳米结构。选取煤化工废水中的酚类物质作为目标污染物模型，探究PDI有机超分子光催化剂对其的高效光氧化降解、矿化过程，同时也致力于探索与提升催化剂在光催化分解水产氧方面的性能。同时结合PDI超分子光催化剂光氧化降解污染物及光解水产氧的反应历程、催化机理的系统研究，揭示催化剂的构-效关系。此外，还将利用贵金属/碳材料、金属氧化物半导体对PDI超分子光催化剂体系光生电子的俘获与导出作用，探究其对有机超分子光催化体系光光生载流子的迁移、分离及超分子稳定性的作用规律。

本项目围绕着高效、高稳定性的可见光型苝酰亚胺（PDI）基超分子光催化体系的可控构建，并通过探究其电子能带结构与光生载流子的迁移、分离能力，结合对体系光氧化降解污染物的反应历程、催化机理的系统研究，揭示出了各催化剂结构与活性间的构-效关系。其主要的结论有：1）依赖于Pt QDs/PDI超分子界面处所形成的肖特基势垒，可成功实现功函较大的Pt QDs对光生电子的快速有效俘获与导出，进而提升了体系光生载流子的分离能力；2）在SnO2（或ZnSnO3）QDs/PDI超分子异质结体系中，接触界面间所形成的内置电场成功驱使了光生电子由PDI超分子转移至SnO2（或ZnSnO3）QDs，进而改善了体系光生载流子的迁移与分离能力。此外，异质结的构建还有效降低了催化反应过程中因电子无法导出而导致的PDI•-的产生，进而显著增强了PDI 超分子聚集体的稳定性；3）通过引入烷氧基侧链所制备得到的新型PDI超分子光催化剂，不仅展现出了优异的光吸收及更高的结构有序度、结晶度与π-π堆积度等，且获得了适宜的亲水性，进而增加了催化剂活性位点与污染物底物溶液的接触面积。该项目加深了对PDI超分子光催化体系活性作用机理的认识，为拓展其作为高效可见光光催化剂在环境与能源领域的应用提供了重要的理论基础。