光催化反应中的光生电荷行为研究与调控

The dynamic behaviors of photogenerated charges in photocatalysts and photocatalytic system determine the performance of photocatalytic reactions. Owing to the unique features of the porous frameworks, the behaviors of photogenerated charges in a porous composite solid is different to other solid materials. The variation in the components of a solid can impact on the separation, transport and recombination of photogenerated charges. Thus, the understanding of the behaviors of photogenerated charges is highly desirable for the exploration of the porous composite solids with photocatalytic properties. In this project, new porous composite solids with particular structures and compositions will be designed, and prepared through well selected synthesis strategies and the control of the reaction conditions. The photocatalytic performance of the porous composite solids in water splitting, conversion of CO2 or alkane molecules will be systematically evaluated. More importantly, the dynamic behaviors of photogenerated charges within photocatalytic system be investigated. The impact of the photogenerated charge behaviors on the functions of the porous composites will be carefully illustrated. The investigation performed in this project on the mechanism and functions of photogenerated charge behaviors is of fundamental and practical significance for the rational design and construction of novel porous composites with photocatalytic properties.

光生电荷在催化剂及反应体系内的动力学行为决定了光催化反应的活性。由于存在特殊的骨架和孔道结构，使得光生电荷在多孔材料内的行为特点有别于其他固体材料。多组分的复合有助于对光生电荷的分离和复合等行为进行调节。本项目拟从多孔复合光催化材料的设计合成出发，发展具有特定组成和结构的多孔复合材料的可控制备；围绕光生电荷在催化剂及反应体系内的微观行为进行深入研究，明确光生电荷分离的驱动力、传输的影响因素及复合速率等；针对光生电荷行为在水的分解、烷烃和二氧化碳的转化等光催化体系中的行为与功效进行系统探索，建立光生电荷行为与反应功效之间的关系，实现对光生电荷行为和催化活性的调控。本项目对于开发新型的多孔复合催化材料、从微观层面认识光生电荷行为的机制与功效、促进光催化体系的实际应用具有重要意义。

以光催化为代表的光电转换体系的核心过程是光生电荷的一系列微观行为。光生电荷的产生、分离、传输以及复合，决定了载流子寿命、催化活性以及光电转化效率等光电转化体系的性能指标。本项目以半导体及新型多孔复合材料为主体，运用多种组装及相关手段，制备及构筑了多种光电转换体系。以表面光伏为技术核心，深入探索光生电荷的微观行为，挖掘各体系的组成、结构和性能之间的关系。根据异质结构的特性，对获得的光生电荷行为特点与体系性能之间的联系进行解析；系统地研究材料/器件的组成结构对光生电荷行为的影响。本研究对于揭示各类光电转换体系的作用规律、指导开发高效的光电转化体系、以及实现光生电荷的定向调控具有一定的意义。