高效宽光谱响应石墨烯量子点异质结的可控构筑与光催化性能研究

The project intends to design and synthesize efficient broad-spectrum light-harvesting materials based on new environmental-friendly graphene quantum dots. First, highly efficient broad-spectrum responsive graphene quantum dots are low-cost, high-quality macro-controllable prepared. The relationship between the light-harvesting micro-mechanism of graphene quantum dots and their material structures is explored by the first-principles calculations. Second, graphene quantum dot heterojunction is prepared by a simple hydrothermal method using mesoporous titania as a carrier. The photocatalytic performances of graphene quantum dot heterojunction are regulated due to the broad-spectrum and electron transfer characteristics of graphene quantum dots. Third, one or more of the noble metal nanoparticles having local surface plasmon resonance effects and mesoporous titania are co-modified graphene quantum dot heterojunctions. The enhanced photocatalytic properties of multi-co modified heterojunctions are investigated. The structure-activity relationship of microstructure and photocatalytic properties is revealed by regulating structures of graphene quantum dot heterojunctions. The separation and dominant mechanisms of photo-generated electrons and holes in photocatalytic reaction process are discussed. The researches provide a theoretical guidance for the design and synthesis of nano-heterojunction catalyst in the future, but also expect to be important applications in the degradation of pollutants and artificial photosynthesis for water-splitting.

本项目拟设计并合成基于新型环境友好石墨烯量子点的高效宽光谱捕光材料。首先，低成本、高质量宏量可控制备宽光谱高效响应的石墨烯量子点，结合第一性原理计算，探究石墨烯量子点捕光的微观机制及其与材料结构的关系；其次，以介孔二氧化钛为载体，采用简单的水热方法实现两者的功能化组装与复合，利用石墨烯量子点的宽光谱吸收性能和电子转移等特性调控二元石墨烯量子点异质结的光催化性能；再次，将一种或多种具有局域表面等离子体共振效应的贵金属纳米粒子与介孔二氧化钛载体共修饰石墨烯量子点异质结，研究多元共修饰对光催化性能的增强作用。系统调控二元或者多元石墨烯量子点异质结的结构，揭示微结构与光催化性能的构效关系，认识光生电子与空穴分离的本质及其在光催化反应过程中的主导机制。研究结果为今后纳米异质结催化剂的设计和合成提供理论指导，同时有望在污染物降解和人工光合成制氢等领域获得重要应用。

本项目主要开展基于新型环境友好石墨烯量子点的高效宽光谱捕光材料的合成。主要研究内容如下：（1）提出表面吸电子/给电子基团调控策略制备全色荧光碳量子点，使量子点对可见光的吸收达到700纳米，接近近红外区域；（2）提出新颖的卤素掺杂策略，获得白色荧光石墨烯量子点，其对整个可见光区域都有很好的吸收；（3）机器学习辅助制备高质量碳量子点；（4）石墨烯量子点的公斤级制备，为石墨烯量子点的工业化应用提供良好的材料基础；（5）石墨烯量子点与多种半导体材料（二氧化钛、氮化碳、钒酸铋和MIL-101(Fe)）形成异质结催化剂，都表现出良好的光催化性能。执行期间研究结果为今后纳米异质结催化剂的设计和合成提供理论指导，同时有望在人工光合成制氢和二氧化碳还原等领域获得重要应用。