Molecular Electrocatalyst Enables Direct Electrochemical Capture and Conversion of CO2 up to Atmospheric Concentration

Abstract

The conversion of low-concentration CO2 streams into fuel is highly desirable for industrial applications, avoiding energy-intensive CO2 capture and concentration. Here, we report a highly active molecular electrocatalyst, fac-[Mn(CO)3(bis-MeNHC)(MeCN)]+ (1-MeCN+), which enables the direct electrochemical reduction of near-atmospheric CO2 concentrations to CO with up to 100% Faradaic efficiency. Voltammetric analysis at varying CO2 concentrations reveals a clear transition between distinct kinetic regimes, shifting from pure kinetic control to a regime dominated by CO2 depletion. Kinetic analysis in the 5%–100% CO2 range reveals a first-order dependence on substrate concentration. Infrared spectroelectrochemistry confirms that the electrogenerated anionic catalyst remains active under extremely diluted CO2 conditions. Computational modeling further supports that the CO2-to-CO conversion mediated by the doubly reduced species is kinetically accessible at atmospheric CO2 levels. This work demonstrates molecular electrocatalysis even at CO2 concentrations as low as 420 ppm (i.e. atmospheric CO2 partial pressure).