交通土建工程中基于有机半导体g-C3N4的光催化降解NOx应用基础研究

NOx in vehicle exhaust is one of the main pollutants in air pollution. Photocatalytic degradation is a new treatment method of NOx without excess energy requirement. Road transportation system is the source of vehicle exhaust. It is widely spread and the concentration of pollutant is high. In this project, copolymer semiconductor g-C3N4 is selected to be used on the surface of civil transportation engineering as photocatalyst for degradation of NOx. Comparing to TiO2, which is the commonly used photocatalyst, the usage rate of solar energy of g-C3N4 is more efficient and its cost is significantly lower. With these benefits, g-C3N4 is especially suitable for road transportation system. The project studies the mechanism, method and feasibility of g-C3N4 for degradation of NOx in civil transportation engineering. The study mainly includes the preparation of g-C3N4 with high surface area and its degradation activity for NOx; microstructure analysis by electron microscope and element analysis; influence of environmental factors on g-C3N4 photocatalytic degradation activity of NOx. This low-cost method for degradation of NOx accords with the strategy of sustainable development in China. The project will provide theoretical and experimental direction for the application of this new method.

汽车尾气中的NOx是引起的大气污染的主要污染物之一。使用光催化方法降解NOx无需额外提供能源，是一种新的NOx处理方法。道路交通系统是汽车尾气污染物产生的源头，具有分布广、污染物浓度高等特点。本项目提出了一种通过在交通土建结构表面涂覆新型光催化材料g-C3N4采用光催化降解道路交通系统中的NOx污染物的方法。g-C3N4与目前常用光催化材料TiO2相比，其太阳光利用率更高而成本更低，符合道路交通系统的特点。项目研究g-C3N4应用于交通土建工程中降解NOx的机理、方法和可行性。研究内容包括高比表面g-C3N4的制备工艺及其降解NOx的性能；利用电镜和元素分析研究其微观结构；研究环境因素对g-C3N4的光催化降解NOx性能的影响。这种低能耗的NOx降解方法符合我国可持续发展战略的需要，本课题将为这种新方法提供理论和试验指导。

使用光催化方法降解污染物无需额外提供能源，是一种新的污染物处理方法。光催化剂在解决能源和环境问题方面具有重要的应用前景，但是目前太阳能转化效率还比较低，制约了光催化技术的应用。本项目利用两种能带匹配的半导体光催化剂构建成异质结来提高量子效率、拓宽光响应范围，以提高光催化降解污染物的效率。本项目主要研究异质结复合光催化剂的设计、制备与降解有机污染物性能。根据能带位置匹配的要求，设计Cr掺杂的SrTiO3/g-C3N4、BiVO4/g-C3N4、Cr掺杂的SrTiO3/CNIC等异质结复合光催化剂。利用Mott-Sckottky、VBXPS等方法研究其能带位置。采用两步法合成异质结复合光催化剂。利用电镜和元素分析研究其界面结构。研究影响异质结复合光催化剂光催化性能的主要因素。研究异质结的光催化降解有机污染物的机理。阐明异质结对光催化性能的影响机制，为拓宽光响应范围、提高光催化的量子效率提供理论和实验指导。