Pathways to reduce the energy cost of carbon monoxide electroreduction to ethylene

CO2-to-CO conversion, followed by CO to value-added products, shows promise as a high-CO2 utilization strategy. However, it is necessary to continue to reduce the energy intensity of CO electrolyzers. Modeling can untangle the highly coupled nature of these electrolyzers and thereby accelerate their optimization. Here, we develop a CO electrolyzer model, which we compare with experiments, and evaluate how it might be possible to attain CO to ethylene (C2H4) with the energy intensity approaching 110 GJ tonne−1 C2H4, then further to an 80 GJ tonne−1 C2H4 target. The model identifies targets and specifications for each component, with the ultimate target requiring continued progress in increasing cathodic catalyst selectivity, thin anion exchange membranes (<25 μm), improved ion exchange capacity (1.7–3.4 mmol/g), enhanced anode activity (>56% overpotential reduction) and thickness (100–400 μm), and optimized operation (1–4 M KOH at 25°C–75°C) at >300 mA cm−2.