基于石墨烯/碳点复合载体的新型光催化材料的可控构建及性能研究

The most important issue for photocatalytic technology is the design and fabrication of visible-light-responsive photocatalysts with high activity and stability. Aiming at the problems of narrower light response range and insufficient quantum efficiency for semiconductor photocatalysts, this project will focus on the construction of novel photocatalytic systems based on graphene/carbon dots (GECDs) hybrid substrate to improve the photocatalytic performance from the aspect of regulating microstructure and component. The feature and law of controlling the shape, size and distribution of semiconductor functional materials on GECDs hybrid substrate will be systematically investigated, so as to achieve the controllable construction of the GECDs-based hybrid materials with expected microstructure. On the basis, the behavior of photogenerated charge carriers separation and the photocatalytic stability of various GECDs-based photocatalysts with different compositions and microstructures, as well as the kinetics of the photocatalytic degradation reaction will be systematically researched. The influence of the composition of GECDs, the size, shape and distribution of semiconductor nanoparticles, and the reciprocity between GECDs and semiconductor on the photocatalytic performance will be investigated in detail, thereby elucidating the structure property relationship of the GECDs-based photocatalysts. It is expected that the study in the project will provide experimental and theoretical guidance for the development of visible-light-responsive photocatalysts.

光催化技术的关键在于设计构建高催化活性和稳定性的可见光光催化材料。本项目针对半导体光催化剂光响应范围窄、量子产率低的问题，拟从微观结构和组分设计角度出发，设计构建新型基于石墨烯/碳点(GECDs)复合载体的光催化体系。系统研究GECDs存在体系中，半导体功能组分的形貌、尺寸、分布的特点和规律，实现具有特定结构的GECDs基复合材料的可控构建。在此基础上，研究不同结构、组分GECDs基复合光催化材料的光生载流子的分离特性，考察光催化动力学行为和所制备的复合光催化材料的稳定性。探讨复合体系中GECDs的组成，半导体纳米单元的尺寸、形态、分布以及GECDs与半导体之间相互作用对光催化性能的影响，阐明GECDs基复合光催化材料的构效关系。项目的实施将为开发具有优异性能的可见光光催化材料提供实验依据和理论指导。

光催化技术的关键在于设计构建高催化活性和稳定性的可见光光催化材料。本项目针对半导体光催化剂光响应范围窄、量子产率低的问题，以性能优异的石墨烯和碳点为活性组分，构建了各种新颖的基于氧化石墨烯（GO）、还原氧化石墨烯（RGO）和氮掺杂碳点（NCDs）的复合光催化材料，如GO-AgIO4、CdS/RGO/γ-Fe2O3、g-C3N4/GO/AgBr、Bi2O4/NCDs、g-C3N4/NCDs/AgBr、g-C3N4/Ag3PO4/NCDs、Ag3PO4/GO/NCDs、AgBiO3/GO/NCDs。利用X-射线衍射、扫描电镜、透射电镜、拉曼光谱、红外光谱、紫外-可见光谱和X-射线光电子能谱等手段对所制备的光催化材料的组成、结构、形貌以及光吸收性质等进行了系统的分析和表征，并利用X-射线光电子价带能谱和紫外光电子能谱研究了半导体的能带结构。系统研究石墨烯和碳点存在体系中，半导体功能组分的成核和生长规律，实现特定结构的复合材料的可控合成。同时以亚甲基蓝、罗丹明B、苯酚和盐酸四环素等为模拟污染物，系统研究了复合材料的组成、结构等对催化性能的影响。研究发现复合材料均表现出了比对应单组份催化剂更强的光催化活性和更好的循环稳定性。此外，通过活性物种捕获实验、电子自旋共振谱、气质联用仪和离子色谱等探讨了催化剂的光催化机理。发现石墨烯和碳点与功能组份间具有强烈的耦合作用，能促进光生电子-空穴对的有效分离、提升催化剂的光吸收能力及分子氧激活能力、改善催化剂的稳定性，对复合材料的光催化性能具有显著的促进作用。本项目研究为开发具有优异性能的可见光光催化材料提供实验依据和理论指导。