伽马辐照制备氧化石墨烯基银纳米颗粒及其表面增强拉曼散射性能研究

发布时间：2018-11-13 20:37

【摘要】：氧化石墨烯基银纳米颗粒(Ag NPs/GO)复合材料具有优异的物化性质,从而在光学、医药、催化等领域具有广阔的应用前景。但目前Ag NPs/GO复合材料的制备路线中均通过超声剥离氧化石墨的方法获得GO,会显著减小GO的片层尺寸,同时过量加入的表面活性剂或功能化试剂会造成Ag NPs的结构缺陷,从而不利于材料整体性能的发挥。此外,在现有的制备路线中还存在过程复杂、污染严重、能耗大等问题,不利于材料的可控宏观制备。因此,Ag NPs/GO复合材料的制备仍然面临着巨大的挑战。60Co伽马(γ)射线辐照技术不仅具有均匀、高效、低污染的特点,还能够在较高的辐照剂量下碎化颗粒的尺寸。此外,根据我们之前的研究表明,γ射线还能诱导层间小分子的生长进而剥离氧化石墨。因此,γ射线辐照法有望成为Ag NPs/GO复合材料的理想制备方案。本论文结合γ射线与阳离子交换技术的优势,通过γ射线辐照层插硝酸咪唑银的氧化石墨前驱体,诱导层间Ag NPs的生长,从而同步实现氧化石墨的剥离和Ag NPs的还原生长,高效获得Ag NPs/GO复合材料。测试结果表明,通过该路线得到的Ag NPs/GO复合材料具有较高的纯度和结晶规整度,高负载量的球形Ag NPs单分散在大尺寸GO表面。同时在对照实验中发现层间Ag NPs的生长会受到氧化石墨的限制。随后我们从Ag NPs在GO片层上呈现抛物线分布及Ag NPs的尺寸随GO层间距的增大而增大两方面来证实了这种现象(层间限制效应)。最后我们从Ag NPs晶体的成核与晶核的生长两个阶段来对Ag NPs结构演化进行机理描述,同时认为氧化石墨的层间限制效应主要影响Ag NPs的核生长阶段,完善了 γ辐照下Ag NPs/GO复合材料的晶体结构演化规律。为Ag NPs/GO复合材料的宏观制备提供一个全新的开发路线和理论基础。此外,在合适的银离子浓度下,能够获得较大颗粒尺寸(13.93nm)和基底完全剥离的Ag NPs/GO复合材料,在Raman化学增强和电磁增强效应的协同作用下使该材料展现出优异的SERS活性,其Raman信号是纯GO的6.3倍。该Ag NPs/GO复合材料制备成的基底对CV的检测灵敏度为10-7、EF=1.3 × 106,表明该SERS基底能够应用于有机染料的检测。
[Abstract]:Because of its excellent physicochemical properties, graphene oxide silver nanoparticles (Ag NPs/GO) composites have wide applications in optics, medicine, catalysis and so on. However, at present, in the preparation of Ag NPs/GO composites, GO, can be obtained by ultrasonic stripping of graphite oxide, and the lamellar size of GO will be significantly reduced. At the same time, excessive addition of surfactants or functionalization reagents will lead to the structure defects of Ag NPs. This is not conducive to the performance of the overall properties of the material. In addition, there are some problems in the existing preparation route, such as complex process, serious pollution and high energy consumption, which is not conducive to the controllable macroscopic preparation of materials. Therefore, the preparation of Ag NPs/GO composites is still facing a great challenge. 60Co gamma (纬) irradiation technology not only has the characteristics of uniform, high efficiency and low pollution, but also can be used to break the size of particles at high irradiation dose. In addition, according to our previous studies, 纬 -rays can also induce the growth of interlaminar small molecules and peel off graphite oxide. Therefore, 纬-ray irradiation is expected to be an ideal preparation method for Ag NPs/GO composites. Combining the advantage of 纬 -ray and cationic exchange technology, this paper induces the growth of interlaminar Ag NPs through 纬 -ray irradiation layer intercalation of silver nitrate with imidazole silver oxide, thus realizing the simultaneous exfoliation of graphite oxide and the reduction growth of Ag NPs. Ag NPs/GO composites were obtained efficiently. The test results show that the Ag NPs/GO composites obtained by this route have high purity and crystallinity, and spherical Ag NPs with high loading amount are monodisperse on the surface of large size GO. At the same time, it was found that the growth of interlaminar Ag NPs was limited by graphite oxide. Then we confirm this phenomenon from two aspects: the parabola distribution of Ag NPs on the GO layer and the increase of the size of Ag NPs with the increase of GO spacing. Finally, we describe the mechanism of Ag NPs structure evolution from two stages of nucleation and nucleation of Ag NPs crystal. At the same time, we think that the interlaminar confinement effect of graphite oxide mainly affects the nuclear growth stage of Ag NPs. The evolution law of crystal structure of Ag NPs/GO composites under 纬 -irradiation was improved. It provides a new development route and theoretical basis for macroscopical preparation of Ag NPs/GO composites. In addition, large particle size (13.93nm) and completely stripped Ag NPs/GO composites can be obtained under the appropriate silver ion concentration. Under the synergistic effect of chemical and electromagnetic enhancement of Raman, the material exhibited excellent SERS activity, and its Raman signal was 6.3 times that of pure GO. The sensitivity of the substrate prepared by the Ag NPs/GO composite to the detection of CV is 10 ~ (-7) F _ (1. 3) 脳 10 ~ (6), which indicates that the SERS substrate can be applied to the detection of organic dyes.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

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