Electrocatalysis for Electroanalysis: Anodic Oxygen-Transfer Reactions at Doped Metal-Oxide Film Electrodes

该项目由爱荷华州立大学化学系Dennis C. Johnson教授指导，由化学系分析和表面化学项目支持。这项工作利用含有掺杂金属氧化物阳极的电化学电池，其电催化性能将在涉及极性有机分子的氧转移氧化研究中得到利用。PI提出氧原子调解是这些氧化进行的机制。将进行旨在提供支持或否定这一机制的证据的实验，并使用数字模拟来证实这一机制。脂肪胺、氨基酸和小肽，其中许多官能团含有硫，是测试化合物。将工作电极制作成适合旋转圆盘电极组件的圆盘，得到电流-电压曲线，并对其力学信息进行分析。利用扫描电子显微镜对电极的表面形貌进行了研究。为了提供更多的信息来支持机理研究，将使用气相色谱-质谱法和电喷雾-质谱法对穷尽电解产物进行化学分析。电化学电池中的电极反应会使参与反应的离子或分子发生化学变化，但在知道这种变化发生的途径之前，对这一过程的科学利用是有限的。这个项目的目的是了解发生在电池阳极的反应的性质，这些反应涉及到氧原子形成产物的转移。有许多化合物可能遵循这样的途径，包括一些生物利益和其他环境问题。所获得的知识的潜在应用被发现在化学分析传感器领域。

This project, supported by the Analytical and Surface Chemistry Program in the Division of Chemistry, is directed by Prof. Dennis C. Johnson of the Chemistry Department at Iowa State University. The work utilizes electrochemical cells containing doped metal oxide anodes whose electrocatalytic properties will be exploited in a study of oxygen-transfer oxidations involving polar organic molecules. Oxygen atom mediation is proposed by the PI as the mechanism by which these oxidations proceed. Experiments designed to provide evidence to support or deny this mechanism will be carried out and digital simulations will be used to confirm mechanisms. Aliphatic amines, amino acids and small peptides, many with functional groups containing sulfur, are the test compounds. Working electrodes fabricated as disks suitable for the rotated disk electrode assembly are used to obtain current-voltage curves which can be analyzed for their mechanistic information. The surface topography of the electrodes is explored using the scanning electron microscope. To provide additional information to support the mechanism studies, chemical analysis of the products of exhaustive electrolysis will be done with gas chromatography-mass spectrometry and electrospray-mass spectrometry. Electrode reactions in electrochemical cells produce chemical changes in the ions or molecules which take part in the reaction but until the pathway is known by which such a change occurs, scientific use of the process is limited. The objective of this project is to understand the nature of reactions taking place at the anode of a cell which involve the transfer of an oxygen atom to form a product. There are many examples of compounds which might follow such a pathway including some of biological interest and others of environmental concern. Potential applications of the knowledge gained are found in the area of sensors for chemical analysis.