Rigorous Evaluation of Liquid Products at High-rate CO2/CO Electrolysis

In this work, the water crossover in CO2 electroly-sis was systematically analyzed with hydrated ions transferring through ion-selective membranes as charge carriers in three-com-partment devices. We demonstrate that the water crossover leads to a variation in the electrolyte volume, which plays an important role in the evaluation of the catalytic selectivity of liquid products. Without considering the water crossover, the catalytic selectivity of liquid products could be overestimated with the use of anion ex-change membranes and underestimated with cation exchange mem-branes. In addition, a protocol for reliably quantifying liquid prod-uct is proposed for high-rate CO2/CO electrolysis in three-compart-ment flow electrolyzers.