單納米粒子電化學
發(fā)布時間：2018-08-03 07:00
【摘要】：隨著科學技術以及社會的發(fā)展,電子產品以及電子器件正趨于微型化,如納電容器。那么開發(fā)一種可以實現對納米粒子進行表征的高靈敏度、高選擇性以及易于控制的分析方法日益迫切。電化學分析方法是儀器分析的一個重要分支,自19世紀初Volta建立了第一個化學電池開始,到兩個世紀后的今天,電化學技術由于其分析快捷、特異性強、成本低廉、易微型化、靈敏度高、需樣量少等優(yōu)點,已經涉及到現代生活的各個領域中。目前,電化學方法研究也已經朝著更加微型化的方向發(fā)展,如何提高靈敏度以及提高檢測的信噪比,實現研究過程的可控性是現代電化學領域面臨的挑戰(zhàn)性課題。本論文主要以電分析化學技術對納米粒子進行了單微粒檢測,并同其他的表征結果進行對照,發(fā)現該方法具有其自身的諸多優(yōu)勢。主要內容概括如下：1以實驗室制備的碳纖維超微圓盤電極作為工作電極,首先針對不具有電活性的納米微粒進行研究。實驗中以金納米粒子作為研究對象,用具有電活性的有機試劑(對羥基苯硫酚,p-HTP)對金納米粒子表面進行功能化。研究了修飾后金納米粒子(p-HTP-AuNPs)在電極上的單微粒電化學響應。結果表明,p-HTP-AuNPs與微電極相互作用過程中,產生的的電荷量較未修飾的金納米粒子有明顯增大。通過與檸檬酸保護的金納米粒子(C-AuNPs)以及戊硫醇修飾的金納米粒子(1-pentanethiol-AuNPs)的電化學響應結果進行對照,同時結合循環(huán)伏安法(CV)、電化學交流阻抗(EIS)等技術對所制備的納米粒子的電化學性能的表征結果,可知p-HTP-AuNPs與微電極相互作用時產生較大電荷量的原因主要是由于功能化試劑中芳環(huán)上離域電子的存在,使得整個修飾后的納米粒子呈現很好的共軛狀態(tài),大大增加電子的傳遞速率,最終導致了較大的電量。并通過瞬態(tài)過程中產生的電量與納米粒子粒徑的平方之間的線性曲線的斜率求得在納米粒子與微電極相互作用過程中產生的電子數目,進一步證明了電量增大的本質原因。此外,利用碰撞頻率與體系中納米粒子濃度之間的關系,對納米粒子的濃度進行表征。2以制備的微懸汞電極作為工作電極,以銀納米粒子(AgNPs)催化H+的還原作為指示反應,研究了AgNPs的單微粒效應。結果表明,相比于汞基電極,H+在銀基電極上有更快的電子傳遞速率,即銀納米粒子可以有效地催化H+的還原,并且對單微粒的銀納納米粒子講行成功表征。之外,該微懸汞電極的性能穩(wěn)定,與碳纖維超微圓盤電極相比,易于實現電極表面更新,使得實驗操作過程便捷高效。3以碳纖維電極作為工作電極,并以氧還原反應作為指示反應,用電化學技術對Pt/C催化劑的單微粒效應進行了研究。結果表明,Pt/C催化劑對氧的還原有很好的催化效果。并且,在Pt/C催化劑的單微粒實驗中,得到了不同于其他研究過程的電流～時間特征曲線。
[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.
【學位授予單位】：西北大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1;O657.1
本文編號：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.
【學位授予單位】：西北大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.1;O657.1
【參考文獻】
相關期刊論文 前5條
1 張黨英;催化劑的發(fā)展前景與思路[J];化工時刊;2004年07期
2 李泉，曾廣賦，席時權;納米粒子[J];化學通報;1995年06期
3 駱夢文;;工業(yè)催化劑的發(fā)展[J];化學通報;1980年06期
4 孫錦宜;氨合成催化劑的發(fā)展[J];中氮肥;1996年02期
5 肖益鴻,蔡國輝,詹瑛瑛,魏可鎂;汽車尾氣催化凈化技術發(fā)展動向[J];中國有色金屬學報;2004年S1期
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