激光液相烧蚀法制备贵金属基核壳纳米结构及其性能研究

发布时间：2018-02-12 15:25

本文关键词： 准分子激光激光液相烧蚀法贵金属基核壳纳米结构光致发光光催化　出处：《北京工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：探索制备材料的新方法是纳米材料学永恒的课题,核壳纳米结构以其单分散性好,可操作性高,稳定性高以及具有自组装性能而备受关注。纳米结构的性能优劣取决于其制备方法,脉冲激光液相烧蚀法是一种简便,快速,适应性广,绿色的制备纳米材料的方法。本文旨在研究采用248 nm准分子脉冲激光液相烧蚀制备贵金属基核壳纳米结构的制备工艺,以及制备产物的表征与产物性能的分析。本文采用248 nm准分子激光在制备贵金属单一纳米结构,贵金属核壳纳米结构和ZnO纳米结构的基础上成功制备了Ag/ZnO核壳纳米结构。采用高分辨透射电子显微镜、紫外可见近红外分光光度计、X射线衍射谱仪以及X射线光电子能谱仪对制备产物的形貌、成分、包覆情况与光吸收效果等进行表征。结果表明:该方法制备的双金属核壳纳米结构与Ag/ZnO核壳纳米结构的表面等离共振特性可以通过控制壳层厚度进行调节,且这一现象与采用Mie理论模拟的核壳结构的光吸收效果一致。采用共聚焦拉曼、光致发光谱和紫外辐照对制备产物的表面增强拉曼、光致发光以及光催化性能进行表征。结果表明:激光烧蚀法制备的贵金属核壳纳米结构具有很强的表面增强拉曼活性,可应用于材料的痕量检测领域;制备的Ag/ZnO核壳纳米结构的紫外发光比ZnO纳米颗粒更强且产生蓝移,经分析表明紫外发光增强是由于Ag与ZnO之间存在电子转移造成的,而峰位蓝移是其纳米结构的量子尺寸效应造成;Ag/ZnO核壳纳米结构具有良好的光催化效果且其光催化效果受Ag含量的影响。本文还结合实验对两步法激光烧蚀制备核壳纳米结构的生成机制分为团聚成核与壳层包覆两个阶段,并进行了分析。
[Abstract]:Exploring new methods of preparing materials is an eternal subject in nanomaterials. Core-shell nanostructures have good monodispersity and high maneuverability. The properties of nanostructures depend on their preparation methods. Pulsed laser liquid phase ablation is a simple, rapid and adaptable method. The preparation process of noble metal based core shell nanostructures by liquid phase ablation with 248 nm excimer pulse laser was studied. In this paper, a 248nm excimer laser was used to prepare a single noble metal nanostructure. Ag/ZnO core-shell nanostructures were successfully prepared on the basis of noble metal core-shell nanostructures and ZnO nanostructures. The morphology and composition of the prepared products by UV-Vis near infrared spectrophotometer and X-ray diffraction spectrometer and X-ray photoelectron spectrometer. The results show that the surface isodissociation resonance of bimetallic core-shell nanostructures and Ag/ZnO core-shell nanostructures can be adjusted by controlling the shell thickness. This phenomenon is consistent with the optical absorption of the core-shell structure simulated by Mie theory. The surface enhanced Raman spectra of the prepared products are obtained by confocal Raman spectroscopy, photoluminescence and ultraviolet irradiation. The photoluminescence and photocatalytic properties were characterized. The results showed that the noble metal core-shell nanostructures prepared by laser ablation had strong surface-enhanced Raman activity and could be used in the field of trace detection of materials. The UV luminescence of the prepared Ag/ZnO core-shell nanostructures is stronger than that of ZnO nanoparticles and the blue shift is produced. The analysis shows that the enhancement of UV luminescence is due to the existence of electron transfer between Ag and ZnO. However, the blue shift of peak position is the quantum size effect of the nanostructure, which results in the good photocatalytic effect of Ag / ZnO core-shell nanostructure and the influence of Ag content on the photocatalytic effect. In this paper, the two-step laser ablation method is also used to prepare the nucleation. The formation mechanism of shell nanostructures can be divided into two stages: agglomeration nucleation and shell coating. And the analysis is carried out.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

【参考文献】