Carbon Monoxide Gas Diffusion Electrolysis that Produces Concentrated C2 Products with High Single-Pass Conversion

Electrochemical CO conversion is critical for the development of alternative fuel and chemical syntheses. To be efficient, electrosynthesis must make concentrated product streams at high rates with modest potentials, but the combination of these features has not been established for CO or the related CO2 electrolysis. Here we investigate CO electrolysis with gas diffusion electrodes (GDEs) supplied by interdigitated flow fields in electrochemical cells with different ion transport properties. By optimizing gas and ion transport, we show that it is possible to simultaneously achieve high current density, high selectivity, and high single-pass conversion at moderate cell potentials. Using a cell with the GDE directly contacting a Nafion membrane, we demonstrate >100 mA cm(-2) CO reduction to C-2 products and direct production of 1.1 M acetate at a cell potential of 2.4 V over 24 hr. Our results reveal critical design features for maximizing the efficiency of C-2 electrosynthesis.