【作者】 段艳林；

【导师】 张晓丽；

【作者基本信息】 山东大学 ， 分析化学， 2007， 硕士

【摘要】 本论文共包括三部分内容，第一章我们制备了几种新型超微电极并对其进行了表征；第二章利用两种自制的微电极作为扫描电化学显微镜（SECM）的超微探头，用两种方法构建了葡萄糖氧化酶（GOx）微米点；第三章将自制的管状电极与SECM在基底表面沉积各种物质和对基底进行表面刻蚀两种方法相结合沉积了金的微图形。第一章我们采用不同的方法分别制作了几种新型的材质、规格及性能特点等各不相同的超微电极：凹形铂微米电极、复合微／微铂电极、碳纤维微米管电极和碳纤维纳米管电极，并利用扫描电化学显微镜、普通光学显微镜、循环伏安法等对其进行了表征，结果证明它们都可以用作SECM的超微探头。第二章利用自制的微电极作为SECM的超微探头，用两种方法直接在铂基底上构建了GOx微米点。一种方法：用直径20μm的凹形铂微米电极作为储存溶液的容器，在大面积铂基底电极上直接构建了GOx的微米点。在此部分工作中我们利用电化学方法研究了GOx在铂电极上的电化学吸附特性，确定了GOx在铂电极上电化学吸附的最佳条件为：GOx浓度为10mg／mL，溶液中含有0.8×10^-3mol／L的Triton X-100，电极吸附电位+1.3V（vs.Ag／AgCl），恒电位时间60 min；然后将通过电化学绝缘和电化学刻蚀相结合的方法制备的凹形铂电极的凹槽作为盛装GOx溶液的容器，利用SECM将其逼近到基底铂电极的上方，通过GOx的电化学吸附直接在铂基底上构建得到了GOx的微米点，并利用SEM及SECM对其进行了表征，证明得到的是有活性的GOx微米点，并确定其直径在20μm左右。另一种方法：利用自制的复合微/微双铂电极作为SECM的笔尖，利用SECM“蘸笔法”直接在铂基底上构建了GOx微米点。此方法将原子力显微镜中的“蘸笔式”纳米刻饰（Dip-Pen nanolithography，DPN）技术的理念运用到SECM中，根据上一部分确定的最佳条件首先将GOx电吸附富集到复合微/微双铂电极的其中一根铂电极上，然后利用SECM将其逼近到铂基底电极上方，吸附了GOx的铂微米电极作为工作电极，另一根铂微米电极同时作为参比和辅助电极，在其上施加一合适电位使GOx先从铂微电极上脱吸到溶液中，同时在基底铂电极上施加GOx最佳的吸附电位，通过吸附—脱吸—再吸附的过程使GOx转移并固定到基底铂电极上，并利用SECM对其活性进行了表征，从而证明得到的是有活性的GOx微米点，其直径在20μm左右。第三章在本实验室利用化学透镜的原理将SECM在基底表面沉积各种物质和对基底进行表面刻蚀两种方法相结合沉积金的方法之上研究了一种新的SECM沉积金的方法—将管状电极与SECM在基底表面沉积各种物质和对基底进行表面刻蚀两种方法相结合沉积金。在此部分工作中碳纤维微米管状电极用作盛装一定浓度的pn为8.2的KAu（CN）₂和KF及NaNO₂混和液的容器同时作为SECM的探头，利用SECM将探头向Si基底逼近并使探头尽量靠近基底，控制条件使管内的溶液在空气中自然流出，同时在碳纤维微电极上施加能够使NO₂^-氧化的正电位+1.5V（vs.Ag／AgCl），使NO₂^-被氧化成NO₃^-，H₂O释放出H⁺，随着反应的不断进行，探头上产生的H⁺逐渐累积，逐渐累积的H⁺随着管状电极内部溶液的流出一同流向Si基底，使基底上方探头附近溶液pH逐渐降低，当降低到一定程度时，Si被氧化并与F结合生成SiF₆^2-，对基底进行刻蚀，同时Au（CN）₂^-被还原成Au，从而实现金的沉积。此方法利用管电极储存大量溶液，解决了DPN方法中“墨水”分子有限的问题，可以连续不断的得到各种各样的图形。利用此方法得到了一系列金的微米图形（点、线、图形、线组合），并利用SECM对其进行了表征，确定其直径在3～5μm之间。更多还原

【Abstract】 This paper consists of three parts.In chapter one of this paper, several new different ultramicroelectrodes were fabricated by different methods and were characterized by scanning elechemical microscopy （SECM）, Optical Microscope and Cyclic Voltammetry. The result was that their performance was good and they all could be used as the probe of SECM.In chapter two, two new methods for GOx micrometer dots fabrication on the platinum substrate electrode with two microelectrodes fabricated by us by SECM were developed. In the first method, a concave platinum micrometer electrode that fabricated by means of phenol-allylphenol copolymer insulation and electrochemical etching was used in the fabrication of GOx micrometer dots on the platinum substrate electrode. First, the electrodepositon of GOx on the platinum electode was achieved by electrochemical method. In the experiment, we found that when the concentration of GOx was 10 mg/mL, the concentration of Triton X-100 was 0.8 mmol/L, the electrodeposition potential on the Pt electrode was +1.3 V （vs. Ag/AgCl）, and the electrodeposition time was 60 min, GOx could be electrodeposited on the electrode best. Then the micrometer dots of GOx were achieved by electrodeposition in this condition with a concave micrometer platinum electrode. In this systerm, the concave Pt micrometer electrode was used both as reference and counter electrode and the substrate Pt electode was used as work electrode. The micropatterns were characterized by both scanning eletron microscope （SEM） and SECM. And we concluded that the diameter of the micropatterns fabricated by this method was about 20 μm. In the second one, GOx micropatterns were fabricated by SECM "Dip-pen" technique with a dual micrometer platinum electrode （DMPE）. The principle of this method was that the elements of "Dip-Pen nanolithography" （DPN） of AFM was utilized in SECM. In this work, GOx was first electrodeposited on one platinum electrode of the DMPE in the condition that had been selected in the first method. After the DMPE was placed upon the substrate platinum work electrode, the microelectrode without GOx was used both as reference and counter electrode, the microelectrode with GOx was used as work electrode, and the substrate platinum electrode was used as another work electrode. Appropriate potentials were applied on the two work electrodes, then GOx was desorbed from the microelectrode and deposited on the substrate platinum electrode at the same time. So the activated patterns were fabricated in the process of electrodeposition - desorption -electrodeposition, and the patterns were characterized by SECM.In chapter three, a new method for gold deposition by SECM with micropipet electrode was developed. In this work, a micropipet electrode filled with electrolyte consisted of KAu（CN）₂, KF, NaNO₃ and a carbon fiber microelectrode used as work electrode, Pt electrode used as counter electrode, Ag/AgCl electrode used as reference electrode in it was used as the probe of SECM. Then a silicon substrate treated with hydrofluoric acid was mounted in a cell and the micropipet electrode moved down toward the substrate. A potential of +1.5V vs Ag/AgCl was applied to the carbon fiber microelectrode and the protons were generated at the micropipet tip by oxidizing nitrite ions. With transfering of electrolyte from across the tip of the micropipet, the protons flowed onto the surface of the silicon substrate and induced the redox reaction between Au（CN）₂^- and silicon. Si was oxidized to SiF₆^2-, at the same time, the Au（CN）₂^- was metallized by taking the electrons released from Si. In this method, that micropipet was used as a vessel which contained a lot of molecules desolved the problem of limited molecules in DPN method. With this method, the micropatterns of gold such as micrometer dots, micrometer lines etc were both fabricated and characterized.更多还原