CHARACTERIZATION OF TRANSIENT ELECTROCATALYTIC INTERMEDIATES BY SERS

通过 SERS 表征瞬态电催化中间体

• 批准号: 6344845
• 负责人: CHARLES M HOSTEN
• 金额: $ 8.82万
• 依托单位: HOWARD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6344845
• 关键词: Raman spectrometry; active sites; ammonia; atomic absorption spectrometry; catalyst; chemical structure; electrochemistry; enzyme activity; nitrate reductases; nitrites; oxidation reduction reaction; photochemistry; porphyrins; radiochemistry

The net 6-electron, five point reduction of nitrite to ammonia is catalyzed by the enzyme nitrite reductase. Electrochemical studies have shown that a series of water soluble porphyrins are efficient electrocatalyst for the conversion of nitrite to ammonia. The proposed spectro-electrochemical study will couple a number of surface- spectroscopic and electrochemical techniques to obtain data on the molecular structure and lifetimes of the porphyrin intermediates, generated during the electrocatalytic reduction. From this data, a comprehensive mechanism for the porphyrin catalyzed electro-reduction of nitrite to ammonia will be developed. The specific spectroscopic techniques to be employed are solution Raman spectroscopy, surface-enhanced Raman spectroscopy, SERS, and its variant, time-resolved SERS, TRSERS, along with UV/Vis absorption spectroscopy. By linking the large enhancement afforded by SERS, with multi-channel detection, molecular structural information on electro-generated catalytic transients on a SERS active electrode surface will be obtained. Radiation chemical and photochemical studies will also be incorporated and these techniques will provide rat constraints for short-lived iron porphyrin intermediates generated by pulse photochemical processes. The electrochemical techniques to be employed include cyclic voltammetry, differential pulse voltammetry and constant potential electrolysis. Electrochemical techniques provide information regarding the rate of the reaction and the influence of diffusion, concentration and temperature. SERS spectroscopy provides information on the chemical identity, structure, configuration and orientation of the surface species. By coupling electrochemical experiments with SERS scattering spectroscopy, both kinetic and structural characteristics of the surface intermediates will be probed. The conclusion derived from this research will find application in the characterization and design of modified electrode surfaces. These modified surfaces possess potential applications in energy conversion processes, light driven reactions and the activation of small biological molecules.

亚硝酸盐的净6电子，五点还原为氨 由亚硝酸还原酶催化。电化学研究已经 表明一系列的水溶性卟啉是有效的。 用于将亚硝酸盐转化为氨的电催化剂。建议数 光谱-电化学研究将耦合一些表面- 光谱和电化学技术，以获得关于 卟啉中间体的分子结构和寿命， 在电催化还原过程中产生。从这些数据中， 卟啉催化氧化还原的综合机理研究 将开发亚硝酸盐制氨技术。 要使用的特定光谱技术是溶液拉曼 光谱学、表面增强拉曼光谱、表面增强拉曼光谱及其变体， 时间分辨SERS，TRSERS，以及UV/Vis吸收光谱。通过 将SERS提供的巨大增强与多通道相结合 电生催化剂的检测、分子结构信息 在SERS活性电极表面将获得暂态。辐射 化学和光化学研究也将被纳入其中，这些 技术将为短命的铁卟啉提供老鼠限制 由脉冲光化学过程产生的中间产物。 要采用的电化学技术包括循环伏安法， 差示脉冲伏安法和恒电位电解法。 电化学技术提供了有关反应速度的信息。 反应以及扩散、浓度和温度的影响。 SERS光谱提供了有关化学特性的信息， 表面物种的结构、构型和取向。通过 将电化学实验与表面增强拉曼散射光谱相结合， 表面中间体的动力学和结构特征 将会被调查。从这项研究得出的结论将会发现 修饰电极在表征和设计中的应用 表面。这些改性表面在能源方面具有潜在的应用前景。 转化过程、光驱动反应和小分子的活化 生物分子。