二维给受体型共价有机框架材料的设计合成、能级调控及光解水性能研究

To achieve the urgent need of the 13th Five-Year Plan for energy development of People’s Republic of China, the proposed project focuses on the main challenges of the photocatalytic water splitting area, such as overall water splitting, low hydrogen and oxygen evolution rate and limited visible-light induced photocatalytic materials. Aim to control the band structures and improve the charge separation efficiency of the photocatalytic covalent organic frameworks (COFs), we propose to introduce the donor-acceptor (D-A) strategy to design and synthesize a series of two-dimensional (2D) COFs materials. The push–pull nature of the D/A units brings the opportunities of tuning the energy levels of 2D-COFs, investigating the corresponding principles and mechanisms, and overcoming the mismatched band position or the lack of a driving force of most COFs materials. The proof-of-principle investigations on the influence of the D-A architecture on the charge separation, transfer and transport processes will also be performed. By systematic variation of the donor/acceptor moieties, the charge separation efficiency of 2D-COFs will be improved. At last, these 2-D D-A COFs will be applied to realize the overall water splitting, and optimize the hydrogen and oxygen evolution, which may serve as preliminary study for developing the COFs based efficient, lightweight and affordable visible-light induced photocatalytic materials.

本项目面向我国“十三五”期间对能源产业发展的重大需求，突破光催化分解水领域全解水难以实现、产氢产氧效率较低、可见光催化材料有限的难题。针对新型共价有机框架（COFs）光催化材料能级结构的有序调控、电荷分离效率的优化等关键科学问题，将给受体型分子设计策略引入二维COFs材料的设计与合成中，开发新型二维给受体型COFs光催化材料。创新性的利用给受体推拉电子效应调控二维COFs材料的能级结构，探索给受体结构的设计准则和能级结构的调控机制，解决传统COFs材料能级不能同时达到水的理想氧化、还原电位的难题。进一步研究给受体设计对二维COFs材料电荷分离、转移与传输过程相关的电荷动力学的影响机制，通过给受体单元的合理组合实现电荷分离与传输效率的提高。构筑具有高光催化性能的二维给受体型COFs光催化材料体系，实现光催化全解水与制氢制氧效率的提升，为拓宽COFs光催化材料体系奠定基础。

本项目面向我国“十三五”期间对能源产业发展的重大需求，突破光催化分解水领域产氢产氧效率较低、可见光催化材料有限的难题。以构筑高效、可控的光催化材料体系的研究目标，重点研究了CdSe、BiOX (X = Cl, Br, I)、BiVO4、TiO2等半导体纳米材料的高效合成，材料表面结构（缺陷态、晶面取向等）的可控调控，材料表面结构与光催化性能之间的构效关系以及相应的光催化反应机理，最终获得了一系列高性能的半导体光催化材料。主要的研究成果如下： 1.利用氨类化合物促进生长法减少了CdSe量子点表面浅电子缺陷态的形成，提升了量子点与助催化剂之间的电荷分离与转移，在7小时内光催化分解水产生了44.5ml的氢气，是传统水热合成法的1.6倍。2.利用两相法成功制备了{001}晶面高度暴露的二维超薄BiOX (X=Cl, Br, I)纳米片。二维超薄BiOX 纳米片具有电荷分离效率高、电子迁移距离短等特点，有效提升了其光催化降解有机物与光催化产氧的性能。3.利用简便的旋涂BiVO4纳米粒子的方法构筑了透光率为70%、且沿[004]晶轴方向具有明显晶体取向的BiVO4光阳极。通过与CsPbBrI2钙钛矿太阳能电池进行串联，实现光照条件下自支持光电催化水分解器件的构筑。4.通过两步溶剂热和溶胶-凝胶包复策略，制备了SiO2 @ TiO2：Eu3 + @ TiO2核双壳微球(STT)。所制备的STT对油田废水中的聚丙烯酰胺具有优异的光催化降解性能。进一步发现了STT的荧光强度与其光催化活性呈相反的相关性。