Scalable electrochemical CO2 reduction to oxalate in a continuous flow reactor

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The electrochemical reduction of CO 2 to oxalate has emerged as a promising pathway for both carbon utilization and negative-emission strategies, as it couples renewable electricity with the production of a high-value platform chemical. In this work, we investigated the electroreduction of CO 2 in a novel designed-flow reactor employing stainless steel cathode in an acetonitrile medium. The reactor design was evaluated by varying electrode spacing (0.5, 1, and 2 mm) and scaling electrode area (from 10 mm 2 to 656 mm²), aiming to enhance mass transport and reduce ohmic losses. Faradaic efficiencies up to 72% and current densities above 130 mA cm −2 were achieved, which surpass previously reported results for flow systems. Notably, scaling up to 656 mm² electrodes maintained competitive efficiency while significantly improving oxalate production rates. These results demonstrate one of the few successful demonstrations of CO 2 -to-oxalate conversion in a continuous-flow configuration, highlighting the potential of reactor engineering approaches for advancing scalable and environmentally benign CO 2 electroreduction technologies.