层状化合物表面担载AgX(X=Cl,Br)/Ag复合光催化剂的构筑及其催化行为机制的研究

The main aim of this proposal is to synthesize and characterize a series of new composite photocatalysts of AgX(X=Cl,Br)/Ag being loaded on layed compound whose activities were based on the synergistic effects between surface plasmon resonance and layered spatial confinement effect and to explore the mechanism of photocatalytic performance for degradation of organic pollutants. The fabrication of nano-sized AgX/Ag on the surface of layered compounds can utilize the synergisitic effects of surface plasmon resonance and nono-ordered-layered-spatial confinement effect to expand the viable light absorption range and enhance the separation efficiency of photo-generated charge carriers, which will overcome the drawbacks of intercalated layered compounds, such as the destruction of layered ordered structure and low efficiency for visible light absorption, which could lead to the decline of photocatalytic activity. The space charge layer distribution of photocatalyst will be optimized and the photoinduced electrons migration characteristics will be improved through the adjustment of preparation conditions and the precise control of the ratio of composite materials, size, shape and chemical composition, so that to achieve the optimized mathch for different bands and to enhance the catalystic activity under visible light irradiation. The implementation of this research will provide new ideas for composing new visible-light-driven photocatalysts from the perspective of composition, structure, and photocatalytic activity. The innovation of this proposal lies in the fact that (1) to improve the photocatalytic activity under visible light irradiation by ultizing the synergistic effects of surface plasmon resonance and layered nano-ordered space, and (2) to establish the mechanism of separation, transfer and capture of photogenerated charges for the AgX/Ag/layered-compound composite photocatalysts.

本项目主要研究系列表面担载AgX(X=Cl,Br)/Ag的复合光催化材料的制备、表征，并探索其可见光下降解有机污染物的活性及其机理。采用软化学合成方法在层状化合物的表面装载纳米AgX/Ag，利用等离子共振效应与层状空间限域效应的协同，拓展可见光吸收范围并促进光生载流子的分离、转移与捕获，以克服插层复合物的层状有序结构被破坏、可见光吸收效率低等问题。探索通过对制备条件的调整及复合材料的比例、尺寸、形貌、化学组成等进行精确控制，优化空间电荷层分布，实现不同能带的优化匹配，改善光生电子的迁移特性，提升材料在可见光下的活性，以实现从材料的组成、结构与光催化活性之间关系的角度设计新型可见光驱动的催化剂的目的。本项目创新性在于①利用表面等离子共振与层状纳米空间限域的协同效应促进可见光催化活性，②建立纳米AgX/Ag/层状化合物上光生载流子分离、转移与捕获的机制。

开发具有可见光相应的光催化材料是光催化技术实际应用的关键，对于利用太阳能处理水体中污染物，解决当前环境治理的难题具有重要意义。本项目在国家自然科学基金(编号51202056)的资助下，通过在层状化合物表面担载具有等离子共振效应的Ag@AgX(X=Cl, Br, I)复合光催化剂，拓展了对可见光的相应范围，提高了光催化活性取得了一系列成果。.本研究将窄带隙的半导体纳米颗粒Ag@AgX(X=Cl, Br, I)均匀负载于层状化合物的表面，大大促进了可见光的响应范围，显示了表面负载具有可见光响应的纳米材料对于促进层状化合物可见光催化活性具有重要的研究潜力。突出的优点是以二维层状间作为反应场，从而能有效的抑制电子-穴的再复合，表现出较高的光催化活性。另外，其具有的多元素、复合型结构也为材料的修饰和改进提供了更广泛的空间，是一类新型高效的多相光催化材料，在光催化降解有机污染物等方面表现出了较高的活性，已成为光催化领域研究热点之一。.本项目主要研究了一系列表面担载Ag@AgX(X=Cl, Br, I)的复合光催化材料，如Ag@AgCl/K2Ti4O9, Ag@AgBr/K2Ti4O9, Ag@AgI/K2Ti4O9, Ag@AgCl/Bi2WO6, Ag@AgBr/Bi2WO6, Ag@AgBr/BiOBr, Cu2O/BiOBr, Cu2O/Bi2WO6等，并探索其可见光下降解有机污染物的活性及其机理。采用新颖的合成方法在层状化合物的表面装载纳米Ag@AgX，通过Ag@AgX的等离子共振效应，将可见光响应范围拓展到700 nm左右，同时实现了等离子共振效应与层状空间限域效应的协同，促进了光生电荷的转移与分离，将可见光下的催化降解有机污染物的活性提高了2-3倍左右，为光催化的实际应用奠定了基础。本项目创新性在于①利用表面等离子共振与层状纳米空间限的协同效应进可见光催化活性，②建立纳米Ag@AgX /层状化合物上光生载流子分离、转移与捕获的机制。.本项目发表SCI论文16篇，其中一区2篇，二区6篇。授权国家发明专利2项，培养硕士研究生7名。