單納米粒子電化學(xué)
發(fā)布時間：2018-08-03 07:00
【摘要】：隨著科學(xué)技術(shù)以及社會的發(fā)展,電子產(chǎn)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(shí)現(xiàn)對納米粒子進(jìn)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(xué)分析方法是儀器分析的一個重要分支,自19世紀(jì)初Volta建立了第一個化學(xué)電池開始,到兩個世紀(jì)后的今天,電化學(xué)技術(shù)由于其分析快捷、特異性強(qiáng)、成本低廉、易微型化、靈敏度高、需樣量少等優(yōu)點(diǎn),已經(jīng)涉及到現(xiàn)代生活的各個領(lǐng)域中。目前,電化學(xué)方法研究也已經(jīng)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(shí)現(xiàn)研究過程的可控性是現(xiàn)代電化學(xué)領(lǐng)域面臨的挑戰(zhàn)性課題。本論文主要以電分析化學(xué)技術(shù)對納米粒子進(jìn)行了單微粒檢測,并同其他的表征結(jié)果進(jìn)行對照,發(fā)現(xiàn)該方法具有其自身的諸多優(yōu)勢。主要內(nèi)容概括如下：1以實(shí)驗(yàn)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(jìn)行研究。實(shí)驗(yàn)中以金納米粒子作為研究對象,用具有電活性的有機(jī)試劑(對羥基苯硫酚,p-HTP)對金納米粒子表面進(jìn)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(xué)響應(yīng)。結(jié)果表明,p-HTP-AuNPs與微電極相互作用過程中,產(chǎn)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(hù)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(xué)響應(yīng)結(jié)果進(jìn)行對照,同時結(jié)合循環(huán)伏安法(CV)、電化學(xué)交流阻抗(EIS)等技術(shù)對所制備的納米粒子的電化學(xué)性能的表征結(jié)果,可知p-HTP-AuNPs與微電極相互作用時產(chǎn)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(xiàn)很好的共軛狀態(tài),大大增加電子的傳遞速率,最終導(dǎo)致了較大的電量。并通過瞬態(tài)過程中產(chǎn)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(chǎn)生的電子數(shù)目,進(jìn)一步證明了電量增大的本質(zhì)原因。此外,利用碰撞頻率與體系中納米粒子濃度之間的關(guān)系,對納米粒子的濃度進(jìn)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(yīng),研究了AgNPs的單微粒效應(yīng)。結(jié)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(shí)現(xiàn)電極表面更新,使得實(shí)驗(yàn)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(yīng)作為指示反應(yīng),用電化學(xué)技術(shù)對Pt/C催化劑的單微粒效應(yīng)進(jìn)行了研究。結(jié)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(shí)驗(yàn)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(xué)位授予單位】：西北大學(xué)
【學(xué)位級別】：碩士
【學(xué)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(xué)位授予單位】：西北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB383.1;O657.1
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