21.11.2021 age). For example, increasing the current density of CO 2 -electrolyzers dedicated to syngas (a mixture of hydrogen and carbon monoxide) production leads to a higher H 2 /CO ratio due to the changes in the Faraday efficiencies toward hydrogen and carbon monoxide . The deviation of the product composition from the nominal level is typically undesired for downstream processes. This feature is distinct from other conventional electrolysis, such as water electrolysis and chlor-alkali electrolysis, in which the product concentrations do not significantly change with respect to the current density. To meet the product specification, a part of the components should be separated, which would complicate the process configuration and worsen the economic viability as well.