10.1021/acsenergylett.9b00975.s002 Yuguang C. Li Yuguang C. Li Geonhui Lee Geonhui Lee Tiange Yuan Tiange Yuan Ying Wang Ying Wang Dae-Hyun Nam Dae-Hyun Nam Ziyun Wang Ziyun Wang F. Pelayo García de Arquer F. Pelayo García de Arquer Yanwei Lum Yanwei Lum Cao-Thang Dinh Cao-Thang Dinh Oleksandr Voznyy Oleksandr Voznyy Edward H. Sargent Edward H. Sargent CO<sub>2</sub> Electroreduction from Carbonate Electrolyte American Chemical Society 2019 syngas product stream CO 2 release CO 2 electrolysis CO 2 CO 2 Electroreduction upgrades carbonate electrolyte CO 2 conversion technologies 2019-05-24 00:00:00 Media https://acs.figshare.com/articles/media/CO_sub_2_sub_Electroreduction_from_Carbonate_Electrolyte/8204594 The process of CO<sub>2</sub> valorizationfrom capture of CO<sub>2</sub> to its electrochemical upgraderequires significant inputs in each of the capture, upgrade, and separation steps. Here we report an electrolyzer that upgrades carbonate electrolyte from CO<sub>2</sub> capture solution to syngas, achieving 100% carbon utilization across the system. A bipolar membrane is used to produce proton in situ to facilitate CO<sub>2</sub> release at the membrane:catalyst interface from the carbonate solution. Using a Ag catalyst, we generate syngas at a 3:1 H<sub>2</sub>:CO ratio, and the product is not diluted by CO<sub>2</sub> at the gas outlet; we generate this pure syngas product stream at a current density of 150 mA/cm<sup>2</sup> and an energy efficiency of 35%. The carbonate-to-syngas system is stable under a continuous 145 h of catalytic operation. The work demonstrates the benefits of coupling CO<sub>2</sub> electrolysis with a CO<sub>2</sub> capture electrolyte on the path to practicable CO<sub>2</sub> conversion technologies.