银基纳米材料的快速制备及其性能研究

发布时间：2018-06-24 11:34

本文选题：银纳米材料 + 快速制备　；参考：《安徽工业大学》2017年硕士论文

【摘要】：银纳米材料具有独特的物理化学性质,在光学、电子学、热学以及生物医药等领域表现出特殊的功能,从而被广泛应用作抗菌材料、催化材料、电子元器件和防静电材料等。众所周知,银纳米材料的性能及应用主要决定于其粒径、形貌和稳定性,因此,银纳米材料的可控制备,己经成为当今纳米材料研究的热点之一。本研究首先以葡萄糖(C_6H_(12)O_6)为还原剂、硝酸银(AgNO_3)为银源,聚乙烯吡咯烷酮(PVP)为分散剂,采用液相还原法在室温水体系中快速制备了不同浓度的银纳米胶体,借助于紫外-可见光分析(UV-Vis)、X-射线分析(XRD)和透射电子显微镜(TEM)对银纳米粒子(Ag nanoparticles,AgNPs)的尺寸、结构和形貌进行了表征,结果表明:当反应体系中AgNO_3与C_6H_(12)O_6摩尔比为1:2,AgNO_3与NaOH的摩尔比为2:(3-4),AgNO_3与PVP的质量比为3:1-4:1,可制得稳定性良好、粒径为30-55 nm、具有面心立方结构(FCC)不同浓度的球形银纳米胶体。同时将制备的AgNPs用于痕量过氧化氢(H_2O_2)的检测,检测表明:银纳米胶体表面等离子共振峰强度变化与H_2O_2浓度呈线性关系,H_2O_2的检测灵敏度高,检测限为5.0′10-7mol/L。其次以高化学活性的铝粉(Al)作为还原剂,氧化银(Ag2O)作为氧化剂,利用燃烧合成法制备了AgNPs,采用场发射扫描电子显微镜(FE-SEM)、XRD和TEM对AgNPs的尺寸、形貌和结构进行了表征,并对AgNPs的形成机理和表面增强拉曼效应进行了研究。结果表明:利用该法可快速制备出具有FCC结构、平均粒径为40nm球形AgNPs。高速摄像测试(HSVR)和密闭爆发器测试(CBT)表明燃烧合成法制备AgNPs的形成机制为:瞬间释放的大量能量使反应以484-840 m/s的速度快速进行并迅速蔓延,且在此过程中银的成核速率大于生长速率。同时以结晶紫(CV)作为探针分子,对AgNPs作为基底的表面增强拉曼效应(SERS)进行了研究,结果证实,CV在AgNPs表面吸附均一,其表面增强拉曼因子平均达到9.35×103。最后以AgNO_3为银源,水热合成的片状二氧化钛(TiO_2)为载体,环三亚甲基三硝胺(RDX)为高能物质,采用爆燃法制备了Ag/TiO_2纳米复合物。XRD、X射线光电子能谱分析(XPS)、TEM和UV-Vis测试结果表明:该法可以实现在TiO_2界面上一步负载5-10 nm的纯相AgNPs。同时考察了其作为催化剂,光催化降解罗丹明B(RhB)的催化活性,结果表明Ag/TiO_2纳米复合物比TiO_2纳米片具有更强的光催化性能,其光催化动力学常数随着AgNPs含量的增加而增大,当AgNO_3与TiO_2纳米片质量比为0.1、0.2和0.3时,光催化动力学常数分别为0.326,0.437和0.511 min-1,是TiO_2纳米片的9.48,12.70和14.85倍。进一步研究表明Ag/TiO_2纳米复合物的光催化机理为纳米银粒子的高导电性和Ag/TiO_2界面的构建使得TiO_2激发产生的电子可以迅速的迁移到银颗粒上,实现光生电子空穴的有效分离并减少其复合机率。
[Abstract]:Due to its unique physical and chemical properties, silver nanomaterials are widely used as antibacterial materials, catalytic materials, electronic components and antistatic materials for their special functions in the fields of optics, electronics, thermodynamics and biomedicine. As we all know, the properties and applications of silver nanomaterials are mainly determined by their particle size, morphology and stability. Therefore, the controllable preparation of silver nanomaterials has become one of the hotspots in the research of nanomaterials. In this study, silver nanoparticles of different concentrations were prepared by liquid phase reduction method with glucose (C _ 6H _ (12) O _ (6) O _ (6) as reductant, silver nitrate (Agno _ 3) as silver source and polyvinylpyrrolidone (PVP) as dispersant. The size, structure and morphology of silver nanoparticles were characterized by UV-Vis X-ray analysis (XRD) and transmission electron microscopy (TEM). The results show that when the molar ratio of AgNOSTAL _ 3 to C _ 6H _ (12) O _ 6 is 1: 2Agno _ 3 to NaOH is 2: (3-4) the mass ratio of Agno _ 3 to PVP is 3: 1-4: 1, the spherical silver nanoparticles with FCC structure (FCC) of different concentrations can be prepared with good stability. At the same time, the AgNPs were used for the determination of trace hydrogen peroxide (H _ 2O _ 2). The results showed that there was a linear relationship between the change of surface plasmon resonance peak intensity of silver nanoparticles and the concentration of H _ 2O _ 2. The detection sensitivity of H _ S _ 2O _ 2 was high, and the detection limit was 5.0 ~ (-7) mol / L. Secondly, Ag-NPs were prepared by combustion synthesis with highly chemically active aluminum powder (Al) as reducing agent and silver oxide (Ag2O) as oxidant. The size, morphology and structure of AgNPs were characterized by field emission scanning electron microscopy (FE-SEM) and TEM. The formation mechanism and surface enhanced Raman effect of AgNPs were studied. The results show that 40nm spherical AgNPs with average particle size can be prepared rapidly by this method. High speed camera test (HSVR) and closed burst test (CBT) showed that the formation mechanism of agNPs prepared by combustion synthesis method was that the reaction was carried out at 484-840 m / s and spread rapidly because of a large amount of energy released instantly. In this process, the nucleation rate of silver is higher than the growth rate. At the same time, the surface enhanced Raman effect (SERS) of AgNPs as substrate was studied with crystal violet (CV) as the probe molecule. The results showed that the adsorption of CV on AgNPs was uniform, and the average surface-enhanced Raman factor was 9.35 脳 103. Finally, Agno _ 3 was used as silver source, TIO _ 2 as carrier and cyclotrimethylene trinitramine (RDX) as high energy substance. The results of X-ray photoelectron spectroscopy (XPS), TEM and UV-Vis measurements of Ag/ TiO-2 nanocomposites prepared by deflagration method show that the pure phase AgNPs with 5-10 nm loading can be realized by this method at the TiOStap2 interface. The photocatalytic degradation of Rhodamine B (RhB) was also investigated. The results showed that Ag- / TiO2 nanocomposites had stronger photocatalytic properties than TiO-2 nanochips, and their photocatalytic kinetic constants increased with the increase of AgNPs content. When the mass ratio of Agno _ 3 to TIO _ 2 is 0.10.2,0.3, the photocatalytic kinetic constants are 0.3260.37 and 0.511 min-1, respectively, which is 9.48% 12.70 and 14.85 times of that of TIO _ 2. Further studies show that the photocatalytic mechanism of Ag- / TiO2 nanocomposites is the high conductivity of Ag nanoparticles and the construction of Ag- / TiO2 interface so that the electrons excited by TiO2 can migrate to the silver particles rapidly. The effective separation of photogenerated electron holes is realized and the recombination probability is reduced.
【学位授予单位】：安徽工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TQ131.22

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