A Guide to the Design and Testing of a Lab-Scale Flow Cell CO2 Electrolyzer with Gas-Diffusion Electrodes

The CO₂ electrolyzer is a pivotal technology for enabling the electrification and decarbonization of the chemical industry. Significant advancements in CO₂ electrolysis have been achieved through research focusing on catalysts, gas-diffusion electrodes (GDEs), and system design. While several guides on electroanalytical techniques and electrolyzer operation exist, a comprehensive guide addressing cell design considerations and their relationship to experimental process parameters is still needed. Herein, we present general guidelines for designing and testing a lab-scale flow cell (F-cell) electrolyzer for CO₂ electrolysis using GDEs. The process begins with fundamental design principles, followed by prototyping and materials selection, and culminates in manufacturing and assembly instructions. This electrolyzer is benchmarked using commercial Ag- and Cu-based catalysts for CO₂ conversion to CO and C-C products, respectively, and several diagnostic tools are demonstrated for characterizing GDE performance in a F-cell electrolyzer. Furthermore, we show that the electrolyzer is compatible with various GDE substrates, including carbon-paper-based and polymer-membrane-based gas-diffusion layers as well as metal mesh electrodes. We anticipate that the principles and guidelines presented here will assist researchers entering the field of CO₂ electrolysis and inspire innovative cell designs tailored to their specific research needs.