Reactive capture of CO2 via amino acid

Reactive capture of carbon dioxide (CO2) offers an electrified pathway to produce renewable carbon monoxide (CO), which can then be upgraded into long-chain hydrocarbons and fuels. Previous reactive capture systems relied on hydroxide- or amine-based capture solutions. However, selectivity for CO remains low (<50%) for hydroxide-based systems and conventional amines are prone to oxygen (O2) degradation. Here, we develop a reactive capture strategy using potassium glycinate (K-GLY), an amino acid salt (AAS) capture solution applicable to O2-rich CO2-lean conditions. By employing a single-atom catalyst, engineering the capture solution, and elevating the operating temperature and pressure, we increase the availability of dissolved in-situ CO2 and achieve CO production with 64% Faradaic efficiency (FE) at 50 mA cm−2. We report a measured CO energy efficiency (EE) of 31% and an energy intensity of 40 GJ tCO−1, exceeding the best hydroxide- and amine-based reactive capture reports. The feasibility of the full reactive capture process is demonstrated with both simulated flue gas and direct air input. The electrosynthesis of CO via integrated capture and conversion of dilute CO2 suffers from low energy efficiency. Here, the authors report an amino acid salt-based system that employs a single-atom catalyst and operates at an elevated temperature and pressure, which enables efficient CO production.