Abstract
Captured CO2 can either be stored or converted into carbon-containing products, but both pathways typically require energy-intensive CO2 release from capture solutions before utilization. Here, we report a bicarbonate electrolyzer that integrates CO2 capture and conversion by directly upgrading (bi)carbonate-rich liquids into syngas while regenerating OH– for continued CO2 capture. The electrolyzer operates at 100 mA cm–2 with an applied voltage of 2.7 V at 50 °C, enabled by a cation exchange membrane architecture and a neutral 3 M KHCO3 anolyte that minimizes the thermodynamic potential for oxygen evolution. This integrated carbon capture and utilization pathway achieves an energy efficiency greater than 50%, making electrochemical conversion of captured CO2 to syngas comparable in efficiency to thermochemical CO2 conversion routes.