We demonstrate a hybrid electrolyzer design for CO₂electrolysis to multicarbon products using a cation exchange membrane and different electrode separations. Reducing the thickness of the catholyte flow field from 5 to 2.4 mm significantly decreases the cell voltage while maintaining longer-term stability.

Electrochemical carbon dioxide reduction to multi-carbon products such as ethylene and ethanol is a promising method to store electricity in chemical bonds and produce bulk chemicals from CO2. Simultaneous consideration of processes taking place at the molecular scale, electrolyser scale, and the process scale is crucial to efficiently move towards commercialization and avoid optimizing for unrealistic operating conditions. This chapter summarizes the relevant considerations at each vantage point and reviews the latest developments in CO2 reduction toward multi-carbon products at different scales.