Improving trade-offs in the figures of merit of gas-phase single-pass continuous CO2 electrocatalytic reduction to formate

The electrochemical conversion of CO2 is gaining increasing attention because it could be considered as an appealing strategy for making value-added products at mild conditions from CO2 captured. In this work, we report a process for the electrocatalytic reduction of CO2 to formate (HCOO-) operating in a continuous way, employing a single pass of the reactants through the electrochemical reactor and using Bi carbon supported nanoparticles in the form of a membrane electrode assembly composed by a Gas Diffusion Electrode, a current collector and a cationic exchange membrane. This contribution presents the best trade-off between HCOO- concentration, Faradaic Efficiency and energy consumption in the literature. We also show noteworthy values of energy consumption required of only 180 kWh·kmol-1 of HCOO-, lower than previous approaches, working at current densities that allow achieving formate concentration higher than 300 g·L-1 and simultaneously, a Faradaic Efficiency close to 90%. The results here displayed make the electrochemical approach closer for future implementation at the industrial scale. The authors of this work would like to acknowledge to the financial support from the MINECO, through the projects CTQ2016-76231-C2-1-R and CTQ2016-76231-C2-2-R (AEI/FEDER, UE). J.S.G acknowledges financial support from VITC (Vicerrectorado de Investigación y Transferencia de Conocimiento) of the University of Alicante (UTALENTO16-02). G.D.S, M.A.G and A.I filed a patent application on the experimental reaction system discussed here.