氧化石墨烯—无机纳米粒子复合材料的可控合成及性能研究

发布时间：2018-04-15 02:34

本文选题：可控合成 + 氧化石墨烯　；参考：《江苏大学》2015年博士论文

【摘要】：石墨烯是由碳原子以sp~2杂化构成的新型碳质纳米材料,具有可延展的二维平面,且只有一个碳原子的厚度,呈现周期性六边形排列的蜂窝状结构。因为其具有传统材料所没有的新颖的物理化学性质,成为最近纳米技术研究关注的热点对象。氧化石墨烯(Graphene Oxide,GO)是石墨经过氧化、剥离处理后的产物,与石墨烯相比,它同样具有二维平面结构和六角形晶格,具备出色的物理化学特性,如热性能、机械性能、光学性质、巨大的比表面积等;并且由于其片层表面和边缘有活泼官能团的存在,如羟基、环氧键、羰基和羧基,使得氧化石墨烯具有良好的溶解性和可改性加工性能。这些使得氧化石墨烯成为纳米复合材料中的一个理想骨架。本文旨在构筑多种尺寸和性能可控的氧化石墨烯基无机纳米复合材料,考察复合物的形貌、结构和性能,探索其在光催化、SERS增强、电化学等领域中的应用。主要研究内容如下:第一,研究不同粒径Au、Ag纳米粒子组装的GO-Au、GO-Ag复合物的可控合成,并考察它们的尺寸依赖性。合成过程包括两个步骤:第一步,合成粒径不同的Au、Ag纳米颗粒或溶胶;第二步,在水-正丁胺合成体系中,将纳米粒子与GO复合。正丁胺除了预插层GO的作用,还起到还原并锚定纳米颗粒于GO上。透射电镜图片显示制备的Au、Ag纳米粒子单分散性较好、尺寸分布均匀,并随机负载在GO片层上;紫外可见光吸收光谱显示,随着粒子尺寸的增大,Au或Ag纳米粒子的表面等离子体共振吸收峰发生了明显的红移。实验结果表明,复合物的一些性能显示出明显的尺寸依赖性。随着Ag纳米粒子尺寸的增加,GO-Ag的表面增强拉曼散射效应明显增加;同时随着Au纳米粒子尺寸的增加,GO-Au催化氧化乙二醇制乙二醛的产率降低。第二,采用不同碳链长度的烷基溴化鞍作为卤源,构建Ag/AgBr/GO纳米复合物。研究复合物的光催化活性和表面增强拉曼散射效应与制备过程中烷基溴化铵的碳链长度的关系。实验结果显示,碳链长度降低时,AgBr光分解为Ag的速率加快,Ag/AgBr/GO的可见光催化活性降低,但SERS效应反而出现增强。拉曼散射研究表明,所制备的Ag/AgBr/GO纳米复合物不仅能够增强GO的拉曼信号,还可以作为SERS基底增强染料分子的拉曼信号。由于兼具光催化活性和SERS效应,Ag/AgBr/GO-CTAB和Ag/AgBr/GO-DTAB纳米复合物可以作为可循环SERS基底重复使用。第三,采用乳化爆燃法制备了纳米氧化铈(CeO_2)、氧化铁(Fe_2O_3)和铁酸铜(CuFe_2O_4),并成功将它们负载到GO上,分别得到GO-CeO_2、GO-Fe_2O_3、GO-CuFe_2O_4。利用X射线衍射、透射电镜以及紫外-可见光吸收光谱对合成样品的结构、形貌进行了表征和分析。结果表明:以爆燃法合成的CeO_2、α-Fe_2O_3、CuFe_2O_4纳米粒子较为纯净,平均粒径分别约为29.1 nm、60.0 nm、13.5 nm;它们负载到GO上后,粒子团聚现象有所改善;GO-CeO_2和GO-CuFe_2O_4在紫外光及可见光区域具有很好的光响应能力。汞灯光照下2小时后,催化剂GO-CeO_2、GO-CuFe_2O_4对罗丹明B的光降解率分别可达92.3%、98.1%。结果表明,所得的GO-CeO_2、GO-CuFe_2O_4具有优异的光催化活性。第四,通过量子点表面包覆的毗啶和化学还原性石墨烯(CCG)之间的π-π堆积方式构筑石墨烯-金属硫化物/硒化物量子点复合材料(CCG-PbS、CCG-ZnS、CCG-CdS、CCG-MnS、CCG-PbSe、CCG-ZnSe、CCG-CdSe)。化学还原性石墨烯借助静电斥力,可以不需要分散剂存在下稳定分散在水中。通过X射线衍射、紫外-可见吸收光谱、透射电镜、拉曼光谱等表征手段,考察了相应复合物的结构、形成机理与性质。在制备过程中,利用吡啶取代量子点表面结合的油胺,制备的石墨烯-量子点复合物能稳定地分散于水或极性溶剂中,使得它们可用于电化学和膜材料的进一步研究和应用。第五,分别采用碳纤维、碳纳米管、氧化石墨烯作为载体,将TiO_2纳米粒子负载到它们的表面上,再将Au纳米粒子负载到TiO_2表层,从而合成了三种具有高效光催化活性的碳载Au/TiO_2复合物。通过X射线衍射光谱、扫描电子显微镜、拉曼光谱等测试表征手段,考察了所得碳载Au/TiO_2复合物的结构、形貌与性能。光催化降解实验数据显示在这三种碳载Au/TiO_2复合材料的光催化存在下,经汞灯照射2 h后亚甲基蓝溶液的降解率分别达到约85%、92%、95%。同时拉曼光谱检测显示,Au/TiO_2/CF、Au/TiO_2/GO具有优秀的表面增强拉曼光谱效应,可以作为SERS检测基底来使用,并且在汞灯照射下可以"清洗"掉表面吸附的上组表面增强拉曼散射实验中的检测分子,实现基底的循环使用。
[Abstract]:Graphene is a new carbon nanomaterials composed of carbon atoms with sp~2 hybridization, with two-dimensional malleable, and only one carbon atom thickness, showing periodic arrangement of hexagonal honeycomb structure. Because of its traditional materials do not have novel physical and chemical properties, has become a hot research object recently nanotechnology the graphene oxide (Graphene Oxide GO) is the product of graphite after oxidation, stripping after treatment, compared with graphene, it also has a planar structure and hexagonal lattice, with excellent physical and chemical characteristics, such as thermal properties, mechanical properties, optical properties, large surface area and so on; and as a result the sheet surface and edge of active functional groups, such as hydroxyl, epoxy bond, carbonyl and carboxyl groups, the graphene oxide has good solubility and can be modified. The processing properties of graphite oxide Graphene has become an ideal framework of nano composite materials. This paper aims to build a variety of sizes and properties of controllable graphene oxide based nano composite materials, the morphology of the complex was researched, the structure and performance, explore the enhancement in the photocatalytic, SERS, electrochemical applications. The main contents are as follows: 1. The effects of particle size Au, Ag nanoparticles GO-Au, controllable synthesis of GO-Ag complex, and investigate their size dependence. The synthesis process consists of two steps: the first step, the synthesis of different size Au, Ag nano particles or sol; in the second step, water - butylamine synthesis system, nanoparticles with the GO composite. In addition to the pre butylamine intercalation of GO, also to restore and anchor the nanoparticles to GO. Transmission electron microscopy images showed that the prepared Au, Ag nanoparticles with good dispersibility, uniform size distribution, and the random load in GO layers ; UV Vis absorption spectra showed that with the increase of particle size, surface plasmon resonance absorption peaks of Au or Ag nanoparticles showed an obvious red shift. The experimental results show that some properties of the complexes show obvious size dependence. With the increase of Ag nanoparticle size, GO-Ag surface enhanced Raman scattering effect at the same time increased; with the increase of Au particle size, reduce the catalytic oxidation of GO-Au ethylene glycol aldehyde two. The yield of second, using alkyl bromide saddle with different chain length as halogen source, construction of Ag/AgBr/GO nanocomposites. The relationship of carbon chain length enhanced Raman scattering effect and preparation process of alkyl ammonium bromide the study of Composite Photocatalytic activity and surface. The experimental results show that the carbon chain length decreased, AgBr light accelerated the decomposition of Ag rate, reduce the photocatalytic activity of Ag/AgBr/GO, but SERS The effect of enhanced Raman scattering studies. It appears that, for Ag/AgBr/GO nanocomposite preparation can not only enhance the Raman signal of GO, but also can be used as a SERS substrate to enhance the Raman signal of dye molecules. Due to the high photocatalytic activity and the effect of SERS, Ag/AgBr/GO-CTAB and Ag/AgBr/ GO-DTAB nanocomposites can be recycled as SERS substrate for repeated use. Third, cerium oxide nanoparticles were prepared by emulsion method (CeO_2), deflagration iron oxide (Fe_2O_3) and copper ferrite (CuFe_2O_4), and the success of their load to GO, GO-CeO_2, GO-Fe_2O_3 and GO-CuFe_2O_4. respectively, using X ray diffraction, transmission electron microscopy and UV Vis absorption spectra of the synthesized samples of the structure, morphology were characterized and analyzed. The results showed that: CeO_2, deflagration synthesis of alpha -Fe_2O_3, CuFe_2O_4 nanoparticles are pure, the average particle size was about 29.1 nm, 60 nm, 13.5 nm ; they are loaded on the GO, the particle agglomeration was improved; the GO-CeO_2 and GO-CuFe_2O_4 has good light response ability under UV and visible light region. The mercury lamp light after 2 hours, the catalyst GO-CeO_2, GO-CuFe_2O_4 on the rhodamine B photodegradation rate can reach 92.3%, the results of 98.1%. showed that the GO-CeO_2, with GO-CuFe_2O_4 the excellent photocatalytic activity. Fourth graphene quantum dots surface coated by pyridine and chemical reduction (CCG) between the Pi Pi stacking structure of graphene metal sulfide / selenide quantum dot composites (CCG-PbS, CCG-ZnS, CCG-CdS, CCG-MnS, CCG-PbSe, CCG-ZnSe, CCG-CdSe). The chemical reduction graphene by electrostatic repulsion, without the presence of dispersants dispersed in water. By means of X ray diffraction, UV Vis absorption spectroscopy, transmission electron microscopy, Raman spectra, investigation of the corresponding complex The structure of complexes, mechanism and properties of formation. In the preparation process, using pyridine substituted oil amine combination of quantum dots on the surface of graphene quantum dot composites can be stably dispersed in water or in a polar solvent, so that they can be used for further research and application of electrochemical and membrane materials fifth. Respectively, using carbon fiber, carbon nanotubes, graphene oxide as the carrier, the TiO_2 nanoparticles loaded onto their surfaces, then Au nanoparticles loaded onto the TiO_2 surface, we synthesized three kinds of compounds with high photocatalytic activity of carbon supported Au/TiO_2. Through X ray diffraction spectroscopy, scanning electron microscopy, Raman spectroscopy. Test the characterization of the structure of the carbon supported Au/TiO_2 complexes, morphology and photocatalytic degradation properties. The experimental data showed the presence of photocatalytic Au/TiO_2 composite material in the three kinds of carbon, the mercury lamp 2 h The degradation rate of methylene blue solution reached about 85%, respectively, 92%, 95%., Au/TiO_2/CF and Raman spectrum detection, Au/TiO_2/GO has excellent surface enhanced Raman scattering effect, can be used as a SERS substrate, and can be "cleansed" surface adsorption on surface enhanced Raman scattering group molecular detection experiment in mercury lamp under the implementation of basal recycling.

【学位授予单位】：江苏大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1;TB33

【参考文献】