(123d) Separation of diluted ethanol produced by CO2 electrolysis can be cost effective

Electrolysis of CO₂ to ethanol, powered by renewable energy, is a promising pathway for a sustainable production of a molecule that can be used both as a precursor for chemical synthesis and as an energy source. However, a key challenge in the realization of the process in the industrial environment is the low concentration of ethanol streams obtained from electrocatalytic reactors (~1 to 10 vol%). As a result, required separation processes are believed to limit the economic viability and the possibilities of the scale-up of the process. Here we report how to overcome this bottleneck and present an experimental report of a tandem electrocatalytic reactor – porous membrane separator that allows to produce a concentrated ethanol stream (up to 40 vol%). By exploring the synergies between the optimal environment necessary for CO₂ electrolysis and subsequent separations, we present an overall process that allows to manufacture ethanol at a cost below the current market benchmark (0.9 USD/l).