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

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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.