二维超薄双面MOF异质结光催化剂的构建及其载流子行为规律研究

Toward the pursuit of superior MOF photocatalysts, it is crucial to improve the efficiencies of charge separation and migration, while few in-depth and systematic studies on this issue are reported currently. In this project, we propose a novel photocatalyst configuration consisting of 2D ultrathin Janus bilayer MOF junctions, which can be synthesized by an electrostatic self-assembly strategy, as a novel research model to investigate the above issue. By series of characterizations including spectroscopy and photo-electrochemical means, we will learn about the surficial and interfacial behaviors of photo-generated charge carriers in such a photocatalyst system, i.e. the rules of interfacial separation as well as surficial migration and reaction for electrons and holes. The performances in photocatalytic water-splitting and CO2 reduction of the present Janus MOF junction catalysts will be evaluated. Finally, we attempt to disclose the interacting mechanism within the structures, charge dynamics and photocatalysis for MOF materials. This project may provide significant guidance for the design of highly-efficient MOF-based photocatalysts.

发展高效MOFs光催化材料的关键之一在于提高光生载流子的分离和迁移效率。当前针对此问题未有比较深入和系统的研究被报道。本项目围绕这一关键科学问题，拟通过静电组装的策略构筑二维超薄双面MOF异质结光催化剂作为新的研究模型，利用光、电化学等多种实验手段了解光生载流子表界面运动行为，试图掌握其光生电子与空穴的界面分离、表面迁移与反应的行为规律，同时结合该构型材料的光解水产氢/产氧、光还原CO2的催化性能，揭示MOF材料体系的结构-载流子行为-光催化性能三者之间的相互关系机制，最终为新型高效稳定MOFs光催化材料的开发提供有价值的理论指导。

金属有机框架（MOFs）材料的光催化效率普遍受制于迟缓的光生电荷分离与迁移过程，同时MOFs较差的结构稳定性也制约其实际应用。本项目探索了超声剥离、碱刻蚀剥离等方法制备出几例二维超薄MOFs片；基于该类材料构建了异质结复合光催化剂，缩短电荷迁移路程并引入电荷分离驱动力，从而优化了光生载流子的动力学行为，提高了光催化分解水制氢以及CO2还原的活性；此外，项目执行过程中还开发出几例稳定MOFs光催化剂，揭示了MOFs配位层结构对其稳定性以及载流子分离与迁移的直接而关键的影响，从分子水平理解了MOFs材料的构效关系。本项目的研究发现将为新型高效稳定MOFs光催化剂的顶层设计提供有价值的指导。