Mechanistic insight into molecular catalysts during electrocatalytic reduction of oxygen and carbon dioxide

该项目的中心目标是开发用于还原氧气和二氧化碳的电催化剂，并通过光谱电化学方法研究它们在操作条件下的结构功能关系。催化系统将基于异双核化合物，其被称为“异Pacman”化合物。它们的特征在于将两个不同的金属配位片段连接到刚性骨架上，使得可以在Pacman裂缝内实现底物的协同活化。在化合物的合成和表征之后，将在均相条件下进行首次反应性研究。因此，将发生化合物在表面上的固定，以允许对电催化活性的研究。均相催化剂与电极表面的连接将通过不同的方法（即锚定单元）实现。阐明锚定单元的类型对电子转移性质以及产物选择性的影响是计划工作的子目标。机理研究将在该项目中发挥重要作用。重点将是表面敏感的在操作光谱方法，如SERRS和SEIRA，这将使中间体的表征，以获得新的见解和更好地理解的基础过程中的O2和CO2的还原，分别。一方面，这些结果可以与生物系统进行比较，另一方面，导致下一代催化系统的开发。氧气选择性还原为水和二氧化碳选择性还原为一氧化碳或甲酸将通过正确选择金属中心、配体和反应条件来实现。优化的催化系统可能是一个有趣的应用在专门设计的燃料电池。

The central aim of the project is the development of electrocatalysts for the reduction of oxygen and carbon dioxide and to study their structure function relationship under in-operando conditions via spectro-electrochemical methods. The catalytic systems will be based on heterodinuclear compounds, which are known as "hetero-Pacman" compounds. They are characterized by the attachment of two different metal coordination fragments to a rigid backbone so that a cooperative activation of a substrate can be achieved within the Pacman cleft. Following the synthesis and characterization of the compounds, they will be tested in first reactivity studies under homogeneous conditions. Hereupon, immobilization of the compounds on surfaces will take place to allow investigations on electrocatalytic activity. The connection of the homogeneous catalysts to the electrode surface will be achieved via different methods (i.e. anchoring units). The elucidation of the influence of the type of anchoring unit on the electron transfer properties as well as product selectivity is a sub goal of the planed work.Mechanistic investigations will play an important role for the project. The focus will be given to surface sensitive in-operando spectroscopic methods such as SERRS and SEIRA that will enable the characterization of intermediates to obtain new insights in and a better understanding of the underlying processes during the reduction of O2 and CO2, respectively. The results can be, on the one hand, compared to biological systems, and, on the other hand, lead to the development of a next generation of catalytic systems. The selective reduction of oxygen to water and carbon dioxide to carbon monoxide or formic acid will be accomplished by the right choice of metal centers, ligands and reaction conditions. The optimized catalytic systems might be interesting for an application in specially designed fuel cells.