含醛基体系中可控合成多形貌金纳米颗粒及其机理研究

发布时间：2018-07-09 22:21

本文选题：金纳米颗粒 + 多形貌　；参考：《天津大学》2015年硕士论文

【摘要】：金纳米颗粒因其独特的光电、催化性质以及显著的量子效应和表面效应而备受关注。金纳米颗粒的尺寸、形貌、结构组成等是决定其特殊性质的主要因素,其中形貌的影响最为突出。因此,为了能够更好地实现金纳米颗粒在未来各个领域的应用,通过简单的化学合成方法可控制备出稳定的多形貌金纳米颗粒是相关领域的重要关注点。在近二十年来,已经报道的利用不同还原和稳定体系合成金纳米颗粒的众多合成方法中,聚乙烯基吡咯烷酮(PVP)是一种极为常用的高效形貌控制剂。但是针对其单体,即N-乙烯基吡咯烷酮(NVP),在金纳米颗粒合成中的研究却未见报道。从理论上分析,NVP分子中包含的氧原子和氮原子可以与金纳米颗粒表面产生较强的选择性化学吸附,进而指导金纳米颗粒的非均向生长并进而形成稳定的具备特定形状的金纳米颗粒。为了验证该分析并填补针对NVP的研究空白,本论文将通过实验研究全面阐述N-乙烯基吡咯烷酮(NVP)在金纳米颗粒合成中的作用并对其作用机理进行分析探讨。通过研究发现:N-乙烯基吡咯烷酮不仅可以同时作为还原剂和稳定剂制备出能够稳定存在的金纳米颗粒,而且还能够诱导金纳米颗粒发生非均向生长,产生常见的六边形和三角形金纳米片。在此发现的基础上,论文针对不同反应条件对该体系制备金纳米颗粒的影响进行了全面系统的实验研究,发现该方法还能制备出棒状和带有支脚的金纳米颗粒。随后,利用傅里叶红外变换光谱、透射电子显微镜、扫描电子显微镜、X射线衍射等测试手段,对N-乙烯基吡咯烷酮合成金纳米颗粒的化学过程以及该体系下的多边形金纳米片的生长机理进行了验证性分析和阐述。在对N-乙烯基吡咯烷酮还原机理的研究过程中,发现N-乙烯基吡咯烷酮在酸性条件下水解生成的乙醛起到了还原剂的作用。受此启发,又直接选用乙醛作为还原剂还原氯金酸制备金纳米颗粒。在向乙醛还原体系中引入PVP作为封装剂之后,制备出了一种全新形貌的金纳米颗粒——三维六角星金纳米颗粒。最后根据六角星金纳米颗粒晶体结构的表征数据提出了一种新颖的机理模型以揭示其特殊形貌的演变过程。
[Abstract]:Gold nanoparticles have attracted much attention due to their unique photoelectric catalytic properties and remarkable quantum and surface effects. The size, morphology and structure composition of gold nanoparticles are the main factors that determine the special properties of gold nanoparticles, among which the influence of morphology is the most prominent. Therefore, in order to better realize the application of gold nanoparticles in various fields in the future, it is an important concern in related fields to control the preparation of stable multi-morphology gold nanoparticles by simple chemical synthesis method. Poly (vinylpyrrolidone) (PVP) is one of the most commonly used morphologies control agents for the synthesis of gold nanoparticles using different reduction and stabilization systems in recent 20 years. However, no studies on the synthesis of gold nanoparticles have been reported for its monomer, N-vinylpyrrolidone (NVP). It is theoretically analyzed that the oxygen and nitrogen atoms contained in the NVP molecule can produce strong selective chemisorption on the surface of gold nanoparticles. Furthermore, it can direct the heterogeneous growth of gold nanoparticles and then form stable gold nanoparticles with specific shape. In order to verify this analysis and fill in the research blank of NVP, the role of N-vinylpyrrolidone (NVP) in the synthesis of gold nanoparticles and the mechanism of NVP are discussed in this paper. It was found that: N- vinylpyrrolidone could not only be used as a reducer and stabilizer to prepare gold nanoparticles, but also could induce the heterogeneous growth of gold nanoparticles. Produces common hexagonal and triangular gold nanoparticles. On the basis of these findings, the effects of different reaction conditions on the preparation of gold nanoparticles in the system were studied in a comprehensive and systematic way. It was found that the method could also produce the gold nanoparticles with rod shape and branched feet. Subsequently, by means of Fourier transform infrared spectroscopy, transmission electron microscope, scanning electron microscope and X-ray diffraction, The chemical process of gold nanoparticles synthesized by N-vinylpyrrolidone and the growth mechanism of polygonal gold nanoparticles in this system were analyzed and expounded. In the study of the reduction mechanism of N-vinylpyrrolidone, it was found that acetaldehyde formed by hydrolysis of N-vinylpyrrolidone under acidic conditions acted as a reductant. Inspired by this, acetaldehyde was directly selected as reducing agent to prepare gold nanoparticles. After PVP was used as encapsulant in acetaldehyde reduction system, a novel gold nanoparticles, three-dimensional hexagonal gold nanoparticles, were prepared. Finally, based on the characterization data of hexagonal gold nanoparticles, a novel mechanism model is proposed to reveal the evolution process of its special morphology.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O614.123;TB383.1

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