基于上转换和光子晶体效应的BiVO4膜的制备及太阳光催化性能

Semiconductor photocatalysis is an effective technique to eliminate waterborne pollutants with ecological risk. It is also one of the most promising technologies for pollution control with practical application value. However, its narrow responsive light spectrum and low photocatalytic efficiency limit its utilization at a large scale. In the project, we propose to construct a TiO2 photonic crystal(PC)-carbon quantum dots(CQDs)/BiVO4 bilayer film with upconversion and PC effects as the photocatalyst. Because of its relatively wide responsive light spectrum and pronounced light absorption ability, high efficiency to separate the photogenerated charge and rapid surface reaction, the bilayer film is believed to have significantly improved efficiency of solar energy utilization and photocatalytic degration of pollutants. In this study, the fabrication and characterization of TiO2PC-CQDs/BiVO4 bilayer film will be first conducted. Its performance and mechanisms in photocatalytic degradation of representative waterborne pollutants and microbes in contaminated water will be further investigated. These efforts will shed light on the effects of the wavelength of band gap of PC and the loading quantity of CQDs on its light absorption ability, charge separation performance and adsorption ability. With this information, the key factors that affect the photocatalytic performance of the bilayer film will be discovered and the mechanisms of photocatalytic degradation of representative waterborne pollutants and microbes will be clarified. The outcomes of this project will greatly contribute to the practical application of photocatalysis technique in water treatment and to the relevant scientific fields.

半导体光催化技术是具有生态风险性污染物的有效净化技术，也是最有应用前景的污染控制新技术之一，如何拓展响应光谱和提高光催化效率是其面临的亟待解决的关键科学问题。本研究拟首次构建基于上转换和光子晶体(PC)效应的TiO2PC-碳量子点(CQDs)/BiVO4双层光催化剂，材料特有的宽响应光谱和较强的光吸收性能、较高的光生电荷分离效率和较快的表面反应速率必将大大提高其太阳能利用效率以及污染物分解能力。本项目首先研究TiO2PC-CQDs/BiVO4双层光催化剂的制备与表征，进而考察其对水中典型污染物及细菌的光催化净化性能，并探索其净化机理，以期阐明PC禁带位置以及CQDs担载量调控，对材料的光吸收性能、电荷分离效率以及吸附性能，进而对其光催化性能的影响机制，初步探明光催化净化水中污染物及细菌的规律特点及反应机理。研究成果将为推进半导体光催化技术向水处理实用化发展做出贡献，并具有重要的科学意义。

针对当前光催化技术研究中常见催化剂响应光谱窄和光生电子和空穴分离效率低的问题，以提高可见光催化剂的光催化效率为目的，设计并制备了具有上转换效应的碳量子点(CQDs)，并将其与BiVO4量子管(m-BiVO4)以及NH2-MIL-125复合，拓展了光催化剂的响应光谱至近红外区域，同时，CQDs具有的优异的光生电荷传递能力，促进了光生电荷的分离效率，进而提高了光催化剂光催化降解有机污染物的性能；通过调控CQDs表面官能团的种类和数量，改变其上转换发光光谱波长及强度，改变上转换发光光谱与BiVO4吸收光谱的匹配度，调控CQDs/BiVO4复合光催化剂的光吸收效率，调控复合催化剂的光催化性能；构建基于上转换和光子晶体(PC)效应的TiO2PC-碳量子点(CQDs)/BiVO4双层光催化剂，材料特有的宽响应光谱和较强的光吸收性能、较高的光生电荷分离效率大大提高了其太阳能利用效率以及污染物分解能力。将构建的高效光催化剂用于水中典型污染物的分解，获得了上转换以及光子晶体效应的应用与催化剂光催化性能提高之间的构效关系，以及光催化污染物降解机理。研究成果将为推动光催化技术向水处理实用化发展做出贡献，并具有重要的科学意义。