分级结构Fe3O4@Ag@SiO2/BiOX(X=Cl,Br,I)磁性纳米催化剂的控制合成及晶面依赖的可见光催化性能研究

This project intends to design a novel and efficient magnetic photocatalyst with a hierarchical structure Fe3O4@Ag@SiO2/BiOX(X=Cl, Br, I)， which exhibit magnetic response ability and high visible light catalytic performance.The visible light absorption can be dramatically improved by constructing the hierarchical structure and adjusting the particle size and morphology of Ag nanoparticles and thickness of SiO2 ; Meanwhile,the high visible light catalytic activity of the magnetic photocatalyst induced by surface plasma resonance absorption of Ag nanoparticles will be studied. The catalytic performance and mechanism and the relationship between the morphology and facet-dependent catalytic activites will also be investigated.The project will systemiclly study the controlled preparation, structure, morphology, facet-dependent catalytic performance and applications in phenolic wastewater .We will focused on solving the visible light ehanced effects on hierarchical structure, the surface plasma resonance absorption of Ag nanoparticles, the morphology and facet-dependent visible catalytic performance. Compared with conventional catalysts,this new magnetic photocatalyst with a hierarchical nanostructure is recyclable and has a high visible light catalytic activity. This project will not only develop a new type of loaded plasmonic photocatalyst with high photocatalytic activities to degradation phenolic compounds, but also provide theoretical and technical support for the application of mixed oxide materials in photocatalytic materials and environment purification.

本项目拟设计合成一种新型高效并具有分级结构的磁性纳米光催化剂Fe3O4@Ag@SiO2/BiOX(X=Cl, Br, I)，使该纳米催化剂兼具良好的磁响应特性和高催化活性等优点。通过调整Ag与SiO2的尺寸及厚度，调控Ag纳米颗粒的等离子共振吸收对可见光催化活性的影响；通过对BiOX晶面及形貌的调控，研究催化剂在不同形貌及晶面暴露下的催化作用机理，揭示"形貌-晶面-催化性能"之间的关系原理；项目将系统研究该磁性纳米催化剂的可控制备、结构、形貌、晶面调控及在含酚废水处理等方面的应用。重点解决纳米分级结构的有效构筑,Ag纳米粒子的等离子共振吸收以及晶面形貌等对可见光催化活性的影响；研究所开发的新型纳米光催化剂将为内蒙古自治区在光催化和水污染控制方面提供经验积累，拓宽晶面依赖型等离子纳米光催化剂在卤氧化物中的应用，为合成其它分级结构纳米材料提供新的思路和理论依据，并为实际应用奠定基础。

我们采用溶剂热法，控制合成了片层厚度可调的BiOCl纳米片和Ag@Fe3O4 /BiOCl复合纳米光催化剂，其光催化性能强烈依赖于（001）晶面的暴露程度。通过对反应参数，如表面活性剂P123和甘露醇的量、反应时间、表面活性剂的类型等的有效调控，对所合成的BiOCl纳米片的尺寸大小、片层厚度、形貌、以及（001）晶面的暴露程度等进行了系统地研究。研究结果表明，具有高氧原子密度分布、暴露高能的（001）晶面，不仅有利于罗丹明B染料的吸附，而且可以加速光生电荷的聚集，捕获O2转变为活性氧物种O2−•。因此，得到的（001）晶面暴露的超薄BiOCl纳米片表现出优异的可见光催化性能。以P123和甘露醇为表面活性剂时，合成的BiOCl纳米片具有优异的光催化性能，在20分钟内，可以将罗丹明B完全降解。我们的研究为设计新型光催化材料以及可见光催化反应提供了新的理论支撑。