Electrochemical analysis at nanometer-scaled electrodes

纳米级电极的电化学分析

基本信息

批准号：
14340232
负责人：
AOKI Koichi
金额：
$ 9.47万
依托单位：
University of Fukui
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The aim of this proposal was to investigate abnormal electrochemical behavior of redox reactions at ultramicroelectrodes when reaction domains are on nanometer scale. The abnormal behavior is exemplified by apparent variation of chemical equilibrium constants, reaction rate constants with electrode size. This behavior has been observed at namometer-scaled materials such as metal nanoparticles, nanometered thin films, and nano-clusters. The electrochemical analysis is favorable for this research in that the ultramicroelectrodes provides nano-meter circumstances as well as their detection on the nanometered scale.The previous data of the relation between redox reaction rate constants and the electrode size were the shift of halfwave potentials of Fe(II)(CN)_6 and Fe(III)(CN)_6 with a decrease in the electrode radii. A criticism was presented in that the complexes might be adsorbed so that the redox behavior should be out of the ordinary behavior. In order to circumvent this criticism, we made efforts of searching other redox systems and fabricating nanometer electrodes. At present, we got extremely large transfer coefficients of ferrocene in dichloroethyne solution and TCNQ in acetonitrile. The large coefficient corresponds to enhancement of reaction rates, supporting quantitatively the higher activation with a decrease in material. In order to remove ambiguity of electrode geometry, theoretical work has been made for the analysis of experimental data. The some models have been presented for explaining the enhancement of the reaction rates. The authors think the enhancement is artially due to under estimation of the electrode radii.

该提案的目的是研究当反应域以纳米尺度为单位时，在超密机电极上氧化还原反应的异常电化学行为。异常行为是通过化学平衡常数明显变化的，反应速率常数具有电极大小。在纳米尺度材料（例如金属纳米颗粒，纳米薄膜和纳米簇）等纳米尺度材料上观察到了这种行为。电化学分析有利于这项研究，因为超密电极提供了纳米表的环境及其在纳米量表上的检测。氧化还原反应速率常数与电极大小之间关系的先前数据是Fe（ii）_6和Fe（iii）_6和fe（iii）（cn）（cn）（cn）_6的半波偏移。提出了批评，因为这些复合物可能会被吸附，以便氧化还原行为应超出普通行为。为了避免这种批评，我们努力搜索其他氧化还原系统并制造纳米电极。目前，我们在二氯乙烷溶液中获得了极大的转移系数和乙腈中的TCNQ。较大的系数对应于反应速率的提高，从而定量地支持较高的激活，而材料的降低。为了消除电极几何形状的歧义，已经为实验数据进行了理论工作。已经提出了一些模型来解释反应速率的提高。作者认为增强是由于电极半径估计的人为所致。