The practical implementation of electrochemical CO2 reduction technology is greatly challenged by significant CO2 crossover to the anode side, where the crossed-over CO2 is mixed with the O2, via interfacial carbonate formation in traditional CO2 electrolyzers. As carbon-neutral initiative has been implemented in many places around the world, CO2 reduction technology must now consider utilization of CO2 on top of commonly considered selectivity and activity. Here we report a porous solid electrolyte reactor strategy to efficiently recover these carbon losses while not sacrificing CO2RR catalytic performances. By creating a permeable and ion-conducting solid electrolyte layer between cathode and anode as a buffer layer, the crossover carbonate can combine with protons generated from anode to form CO2 gas again without mixing with anode O2 for a direct reuse. Using silver nanowire catalyst for CO2 reduction to CO as a case study, we demonstrated up to 90% recovery of the crossover CO2 in an ultrahigh gas purity form (&gt; 99%), while delivering over 90% CO Faradaic efficiency under high current density of 200 mA/cm2. This investigation was further implemented to other CO2RR catalysts- Ni single atom, Bi nanosheets, and Cu nanoparticles- to demonstrate its versatility towards various CO2RR systems and products. Also, high continuous CO2 conversion efficiency of over 90% was achieved by recycling the recovered CO2 back to the CO2 input stream demonstrating an electrolyzer system which utilizes most of the CO2 inputted into the device.

Recovering carbon losses in CO2 electrolysis using a solid electrolyte reactor

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.