To convert waste carbon dioxide (CO₂) into valuable chemicals and fuels, electrolyzers must be integrated with an upstream CO₂ capture step. However, this integration has not been demonstrated due to the mismatched rates between CO₂ capture and conversion. We present an integrated CO₂ capture-conversion system that produces syngas with a 1.7:1 H₂ to CO ratio at steady state, where the capture rate matches the release rate in the electrolyzer. The system uses a packed-bed absorber where K₂CO₃ solutions react with CO₂ from simulated flue gas to form (bi)carbonate-enriched solutions, which are then fed into an electrolyzer to produce CO and OH⁻. The alkaline product is recycled to the absorber, completing the CO₂ capture-conversion loop. With glycine as a CO₂ capture promoter, the system captures 30% of carbon from simulated flue gas with a Faradaic efficiency of 30% for CO₂ conversion to CO at 100 mA cm⁻² over 30 h.

中文翻译：

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集成 CO2 捕获和转化以形成合成气


为了将废弃的二氧化碳 （CO₂） 转化为有价值的化学品和燃料，电解槽必须与上游的 CO₂ 捕获步骤集成在一起。然而，由于 CO₂ 捕获和转化之间的速率不匹配，这种集成尚未得到证明。我们提出了一种集成的 CO₂ 捕获转化系统，该系统在稳态下生产 H₂ 与 CO 比率为 1.7：1 的合成气，其中捕获速率与电解槽中的释放速率相匹配。该系统使用填充床吸收器，其中 K₂CO₃ 溶液与模拟烟气中的 CO₂ 反应形成富含（双）碳酸盐的溶液，然后将其送入电解槽以产生 CO 和 OH⁻。碱性产物被回收到吸收器中，完成 CO₂ 捕获-转化循环。使用甘氨酸作为 CO₂ 捕获促进剂，该系统从模拟烟气中捕获 30% 的碳，在 30 小时内以 100 mA ^cm-2 将 CO₂ 转化为 CO 的法拉第效率为 30%。