Time-resolved vibrational spectroscopic study of electrode dynamics

本课题旨在利用快速时间分辨红外光谱技术研究电极动力学和动力学。表面增强红外吸收光谱(SEIRAS)的使用使得能够在皮秒范围内进行超快时间分辨研究。主要成果如下：1.超快时间分辨红外光谱时间常数为0.1-1ms的双层充电阻碍了超快电极动力学的研究。通过将所谓的温度跳跃方法与皮秒时间分辨SEIRAS相结合，首次绕过了这个问题。激光脉冲对界面的快速加热通过水的重新定向导致电位的突然变化。2.在硅棱镜和锗棱镜上制备非常稳定的Seira活性金属薄膜电极的简单和经济有效的技术进展。这些技术极大地促进了上述皮秒时间分辨红外研究的成功。3.分子SCA…对电化学振荡的更多分析在电化学界面上发生各种振荡。我们用时间分辨SEIRAS研究了甲酸在铂电极上氧化过程中的电势和电流振荡，并提出了一个新的概念来解释这种振荡。4.从分子水平上详细研究了构成低温燃料电池基础的铂电极上C_1分子的电催化析氢、氧还原和阳极氧化。我们首次清楚地表明，所有的C_1分子都是通过甲酸盐氧化CO_2的，这完全修正了一般的共识。5.利用SEIRAS作为分子识别系统的模型体系，研究了金电极上自组装的腺嘌呤衍生物和硫胺衍生物之间的自组装单分子膜(SAMS)氢键配对的结构和功能。我们还成功地利用三Ru络合物制备了新型的自组装膜。用SEIRAS分析了它们的结构和功能。较少

This project aimed at to study electrode kinetics and dynamics by using fast time-resolved infrared spectroscopy. The use of surface-enhanced infrared absorption spectroscopy (SEIRAS) enabled ultrafast time-resolved study in the picosecond range. The main achievements are as follows.1.Ultrafast time-resolved IR spectrscopyDouble-layer charging with a 0.1-1 ms time constant has hampered the study of ultrafast electrode dynamics. This problem was circumvented for the first time by coupling the so-called temperature jump method with picosecond time-resolved SEIRAS. The rapid heating of the interface by a laser pulse results in the sudden change in potential through reorientaion of water.2.Technical developments in SEIRASSimple and cost-effective techniques to prepare very stable SEIRA-active thin metal film electrodes on Si and Ge prisms have been developed. These techniques significantly contributed to the success of the picosecond time-resolved IR studies mentioned above.3.Molecular sca … More le analysis of electrochemical oscillationsA variety of oscillations occur at the electrochemical interface. We investigated potential and current oscillations during formic acid oxidation on Pt by time-resolved SEIRAS and proposed a new concept that explains the oscillations without any assumptions.4.ElectrocatalysisHydrogen evolution, oxygen reduction, and anodic oxidation of C_1 molecules on Pt electrodes that constitute the basis of low temperature fuel cells were examined in detail at the molecular scale. We clearly showed for the first time that all C_1 molecules are oxidized CO_2 via formate, which totally revised the general consensus.5.Structures and functions of self-assembled monolayers (SAMs)Hydrogen bond pairing between an adenine derivative self-assembled on an Au electrode and a thimidine derivative were examined by SEIRAS as a model system of molecular recognition system. We also succeeded in fabricating new types of SAMs using triruthenium complexes. Their structures and functions were examined by SEIRAS. Less