Recovering carbon losses in CO₂ electrolysis using a solid electrolyte reactor

The practical implementation of electrochemical CO₂ reduction technology is greatly challenged by notable CO₂ crossover to the anode side, where the crossed-over CO₂ is mixed with O₂, via interfacial carbonate formation in traditional CO₂ electrolysers. Here we report a porous solid electrolyte reactor strategy to efficiently recover these carbon losses. By creating a permeable and ion-conducting sulfonated polymer electrolyte between cathode and anode as a buffer layer, the crossover carbonate can combine with protons generated from the anode to re-form CO₂ gas for reuse without mixing with anodic O₂. Using a silver nanowire catalyst for CO₂ reduction to CO, we demonstrated up to 90% recovery of the crossover CO₂ in an ultrahigh gas purity form (>99%), while delivering over 90% CO Faradaic efficiency under a 200 mA cm⁻² current. A high continuous CO₂ conversion efficiency of over 90% was achieved by recycling the recovered CO₂ to the CO₂ input stream. [Figure not available: see fulltext.]