Model-based Analysis of Oxygen and CO2 Reduction Reaction Kinetics on Silver Electrodes

本课题研究了氧（ORR）和二氧化碳（CO2R）在多晶银电极上的还原动力学。目的是提高对非典型条件下电化学反应动力学的基本理解，例如在高浓度溶液（ORR）和副反应（CO2R）中。此外，本项目的结果将用于了解ORR和CO2R在技术气体扩散电极中的局限性。研究这一过程的方法选择是非线性频响分析（NFRA）。考虑到科学界对非线性动力方法的高度兴趣，本项目的另一个目标是进一步发展NFRA方法。这将通过系统地研究银电极上的各种电化学反应（ORR， HER, CO2R）成为可能，这些反应涵盖了广泛的复杂电化学反应机制（包括电化学，化学步骤和电解质中的先前反应）。ORR和CO2R反应包括中间产物（过氧化氢）或副产物（H2）的形成，与期望产物（ORR和CO2R分别为OH和CO）相比，它们降低了选择性。因此，证明周期性操作是否会影响CO2R的产物选择性是很有趣的，这不仅具有实际意义，而且具有重要的基础意义。

In this project kinetics of oxygen (ORR) and carbon dioxide reduction (CO2R) on polycrystalline silver electrodes are studied. The aim is to improve the basic understanding of the kinetics of electrochemical reactions under atypical conditions, e.g. in highly concentrated solutions (ORR) and in presence of side reactions (CO2R). In addition, the results of this project will be used to understand the limitations of ORR and CO2R in technical gas diffusion electrodes. The method of choice to study this processes is nonlinear frequency response analysis (NFRA). Having in mind high interest of scientific community in nonlinear dynamic methods, another objective of this project is to further develop NFRA method. This will be possible through the systematic investigation of various electrochemical reactions on a silver electrode (ORR, HER, CO2R), which cover a wide range of complex electrochemical reaction mechanisms (with electrochemical, chemical steps and previous reactions in electrolytes). The ORR and CO2R reactions include the formation of intermediate (hydrogen peroxide) or by-products (H2) which reduce selectivity compared to the desired product (OH and CO for ORR or CO2R respectively). Therefore it is interesting to demonstrate whether periodic operation can influence product selectivity for CO2R, which is not only of practical but also of fundamental importance.