Electrochemical carbon dioxide (CO₂) reduction is a promising strategy to synthesize valuable multi-carbon products (C₂₊) while sequestering CO₂ and utilizing intermittent renewable electricity. For industrial deployment, CO₂ electrolyzers must remain stable while selectively producing concentrated C₂₊ products at high rates with modest cell voltages. Here, we present a membrane electrode assembly (MEA) electrolyzer that converts CO₂ to C₂₊ products. We perform side-by-side comparisons of state-of-the-art electrolyzer systems and find that the MEA provides the most stable cell voltage and product selectivity. We then demonstrate an approach to release concentrated gas and liquid products from the cathode outlet. This strategy achieves ∼50% and ∼80% Faradaic efficiency for ethylene and C₂₊ products, respectively, with cathode outlet concentrations of ∼30% ethylene and the direct production of ∼4 wt % ethanol. We characterize stability by operating continuously for 100 h, the longest stable ethylene production at current densities >100 mA cm⁻² among reported CO₂ electrolyzers.

减少电化学二氧化碳（CO ₂）是一种有希望的策略，可以在隔离CO ₂并利用间歇性可再生电力的同时合成有价值的多碳产物（C ₂₊）。对于工业应用，CO ₂电解槽必须保持稳定，同时以适度的电池电压以高速率选择性生产浓缩的C ₂₊产品。在这里，我们介绍了一种将CO ₂转化为C ₂₊的膜电极组件（MEA）电解器产品。我们对最先进的电解器系统进行了并行比较，发现MEA提供了最稳定的电池电压和产品选择性。然后，我们演示了一种从阴极出口释放浓缩的气体和液体产品的方法。该策略对于乙烯和C ₂₊产品分别实现约50％和约80％的法拉第效率，阴极出口浓度为约30％的乙烯和直接生产约4 wt％的乙醇。我们通过连续运行100小时来表征稳定性，这是报告的CO ₂电解池中电流密度> 100 mA cm ^-2时最长的稳定乙烯生产。