单纳米粒子电化学
发布时间：2018-08-03 07:00
【摘要】：随着科学技术以及社会的发展,电子产品以及电子器件正趋于微型化,如纳电容器。那么开发一种可以实现对纳米粒子进行表征的高灵敏度、高选择性以及易于控制的分析方法日益迫切。电化学分析方法是仪器分析的一个重要分支,自19世纪初Volta建立了第一个化学电池开始,到两个世纪后的今天,电化学技术由于其分析快捷、特异性强、成本低廉、易微型化、灵敏度高、需样量少等优点,已经涉及到现代生活的各个领域中。目前,电化学方法研究也已经朝着更加微型化的方向发展,如何提高灵敏度以及提高检测的信噪比,实现研究过程的可控性是现代电化学领域面临的挑战性课题。本论文主要以电分析化学技术对纳米粒子进行了单微粒检测,并同其他的表征结果进行对照,发现该方法具有其自身的诸多优势。主要内容概括如下：1以实验室制备的碳纤维超微圆盘电极作为工作电极,首先针对不具有电活性的纳米微粒进行研究。实验中以金纳米粒子作为研究对象,用具有电活性的有机试剂(对羟基苯硫酚,p-HTP)对金纳米粒子表面进行功能化。研究了修饰后金纳米粒子(p-HTP-AuNPs)在电极上的单微粒电化学响应。结果表明,p-HTP-AuNPs与微电极相互作用过程中,产生的的电荷量较未修饰的金纳米粒子有明显增大。通过与柠檬酸保护的金纳米粒子(C-AuNPs)以及戊硫醇修饰的金纳米粒子(1-pentanethiol-AuNPs)的电化学响应结果进行对照,同时结合循环伏安法(CV)、电化学交流阻抗(EIS)等技术对所制备的纳米粒子的电化学性能的表征结果,可知p-HTP-AuNPs与微电极相互作用时产生较大电荷量的原因主要是由于功能化试剂中芳环上离域电子的存在,使得整个修饰后的纳米粒子呈现很好的共轭状态,大大增加电子的传递速率,最终导致了较大的电量。并通过瞬态过程中产生的电量与纳米粒子粒径的平方之间的线性曲线的斜率求得在纳米粒子与微电极相互作用过程中产生的电子数目,进一步证明了电量增大的本质原因。此外,利用碰撞频率与体系中纳米粒子浓度之间的关系,对纳米粒子的浓度进行表征。2以制备的微悬汞电极作为工作电极,以银纳米粒子(AgNPs)催化H+的还原作为指示反应,研究了AgNPs的单微粒效应。结果表明,相比于汞基电极,H+在银基电极上有更快的电子传递速率,即银纳米粒子可以有效地催化H+的还原,并且对单微粒的银纳纳米粒子讲行成功表征。之外,该微悬汞电极的性能稳定,与碳纤维超微圆盘电极相比,易于实现电极表面更新,使得实验操作过程便捷高效。3以碳纤维电极作为工作电极,并以氧还原反应作为指示反应,用电化学技术对Pt/C催化剂的单微粒效应进行了研究。结果表明,Pt/C催化剂对氧的还原有很好的催化效果。并且,在Pt/C催化剂的单微粒实验中,得到了不同于其他研究过程的电流～时间特征曲线。
[Abstract]:With the development of science and technology and society, electronic products and electronic devices are becoming miniaturized, such as nano capacitors. Therefore, it is increasingly urgent to develop a highly sensitive, selective and easily controlled analytical method for the characterization of nanoparticles. Electrochemical analysis is an important branch of instrument analysis. From the beginning of the 19th century when Volta established the first chemical battery, to two centuries later, electrochemical technology is easy to miniaturize because of its fast analysis, strong specificity, low cost and easy miniaturization. High sensitivity, small sample requirements and other advantages, has been involved in all areas of modern life. At present, the research of electrochemical methods has been developing towards more miniaturization. How to improve the sensitivity and the signal-to-noise ratio (SNR) of detection and realize the controllability of the research process is a challenging subject in the field of modern electrochemistry. In this paper, the single particle of nanoparticles was detected by electroanalytical chemistry, and compared with other characterization results, it was found that this method has many advantages. The main contents are summarized as follows: (1) the carbon fiber ultrafine disk electrode prepared in the laboratory is used as the working electrode. Firstly, the non-electrically active nanoparticles are studied. The surface of gold nanoparticles was functionalized with p-hydroxyphenylthiophenol p-HTP (p-hydroxyphenylthiophenol p-HTP). The electrochemical response of the modified gold nanoparticles (p-HTP-AuNPs) on the electrode was studied. The results show that the charge produced in the interaction between p-HTP-AuNPs and the microelectrode is much larger than that of the unmodified gold nanoparticles. The electrochemical responses of gold nanoparticles (C-AuNPs) and pentylmercaptan modified gold nanoparticles (1-pentanethiol-AuNPs) were compared with those of citric acid protected gold nanoparticles (C-AuNPs) and amyl mercaptan modified gold nanoparticles (1-pentanethiol-AuNPs). At the same time, the electrochemical properties of the prepared nanoparticles were characterized by cyclic voltammetry (CV),) electrochemical impedance (EIS) and other techniques. It can be seen that the main reason for the interaction between p-HTP-AuNPs and the microelectrode is the existence of delocalized electrons on the aromatic ring in the functionalized reagents, which makes the whole modified nanoparticles show a good conjugated state. The electron transfer rate is greatly increased, resulting in a large amount of electricity. Through the slope of the linear curve between the electric quantity produced in the transient process and the square of the particle size, the number of electrons produced in the process of interaction between the nanoparticles and the microelectrode is obtained, which further proves the essential reason for the increase of the electric quantity. In addition, using the relationship between the collision frequency and the concentration of nanoparticles in the system, the concentration of nanoparticles was characterized by using the prepared microsuspension mercury electrode as the working electrode and the reduction of H catalyzed by silver nanoparticles (AgNPs) as the indicative reaction. The single particle effect of AgNPs was studied. The results show that the electron transfer rate of H on silver based electrode is faster than that of mercury based electrode, that is, silver nanoparticles can effectively catalyze the reduction of H, and the silver nanoparticles of single particle can be characterized successfully. In addition, the performance of the microsuspension mercury electrode is stable, compared with the carbon fiber ultrafine disk electrode, it is easy to realize the surface renewal of the electrode, which makes the experimental operation process convenient and efficient, using carbon fiber electrode as the working electrode. The single particle effect of Pt/C catalyst was studied by electrochemical technique with oxygen reduction reaction as indicator reaction. The results show that Pt- / C catalyst has a good catalytic effect on oxygen reduction. In addition, in the single particle experiment of Pt/C catalyst, the current-time characteristic curves are obtained, which are different from other research processes.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O657.1
本文编号：2160937
[Abstract]:With the development of science and technology and society, electronic products and electronic devices are becoming miniaturized, such as nano capacitors. Therefore, it is increasingly urgent to develop a highly sensitive, selective and easily controlled analytical method for the characterization of nanoparticles. Electrochemical analysis is an important branch of instrument analysis. From the beginning of the 19th century when Volta established the first chemical battery, to two centuries later, electrochemical technology is easy to miniaturize because of its fast analysis, strong specificity, low cost and easy miniaturization. High sensitivity, small sample requirements and other advantages, has been involved in all areas of modern life. At present, the research of electrochemical methods has been developing towards more miniaturization. How to improve the sensitivity and the signal-to-noise ratio (SNR) of detection and realize the controllability of the research process is a challenging subject in the field of modern electrochemistry. In this paper, the single particle of nanoparticles was detected by electroanalytical chemistry, and compared with other characterization results, it was found that this method has many advantages. The main contents are summarized as follows: (1) the carbon fiber ultrafine disk electrode prepared in the laboratory is used as the working electrode. Firstly, the non-electrically active nanoparticles are studied. The surface of gold nanoparticles was functionalized with p-hydroxyphenylthiophenol p-HTP (p-hydroxyphenylthiophenol p-HTP). The electrochemical response of the modified gold nanoparticles (p-HTP-AuNPs) on the electrode was studied. The results show that the charge produced in the interaction between p-HTP-AuNPs and the microelectrode is much larger than that of the unmodified gold nanoparticles. The electrochemical responses of gold nanoparticles (C-AuNPs) and pentylmercaptan modified gold nanoparticles (1-pentanethiol-AuNPs) were compared with those of citric acid protected gold nanoparticles (C-AuNPs) and amyl mercaptan modified gold nanoparticles (1-pentanethiol-AuNPs). At the same time, the electrochemical properties of the prepared nanoparticles were characterized by cyclic voltammetry (CV),) electrochemical impedance (EIS) and other techniques. It can be seen that the main reason for the interaction between p-HTP-AuNPs and the microelectrode is the existence of delocalized electrons on the aromatic ring in the functionalized reagents, which makes the whole modified nanoparticles show a good conjugated state. The electron transfer rate is greatly increased, resulting in a large amount of electricity. Through the slope of the linear curve between the electric quantity produced in the transient process and the square of the particle size, the number of electrons produced in the process of interaction between the nanoparticles and the microelectrode is obtained, which further proves the essential reason for the increase of the electric quantity. In addition, using the relationship between the collision frequency and the concentration of nanoparticles in the system, the concentration of nanoparticles was characterized by using the prepared microsuspension mercury electrode as the working electrode and the reduction of H catalyzed by silver nanoparticles (AgNPs) as the indicative reaction. The single particle effect of AgNPs was studied. The results show that the electron transfer rate of H on silver based electrode is faster than that of mercury based electrode, that is, silver nanoparticles can effectively catalyze the reduction of H, and the silver nanoparticles of single particle can be characterized successfully. In addition, the performance of the microsuspension mercury electrode is stable, compared with the carbon fiber ultrafine disk electrode, it is easy to realize the surface renewal of the electrode, which makes the experimental operation process convenient and efficient, using carbon fiber electrode as the working electrode. The single particle effect of Pt/C catalyst was studied by electrochemical technique with oxygen reduction reaction as indicator reaction. The results show that Pt- / C catalyst has a good catalytic effect on oxygen reduction. In addition, in the single particle experiment of Pt/C catalyst, the current-time characteristic curves are obtained, which are different from other research processes.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O657.1
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